**Hand Hygiene Knowledge and Practices among Domestic Hajj Pilgrims: Implications for Future Mass Gatherings Amidst COVID-19**

**Hashim Mahdi 1,2,3,\* ,**† **, Amani Alqahtani 4,**† **, Osamah Barasheed <sup>5</sup> , Amjad Alemam <sup>6</sup> , Mohammed Alhakami <sup>7</sup> , Ibrahim Gadah <sup>8</sup> , Hadeel Alkediwi <sup>9</sup> , Khadijah Alzahrani <sup>9</sup> , Lujain Fatani <sup>10</sup>, Lamis Dahlawi <sup>11</sup>, Saeed Alsharif <sup>12</sup>, Ramon Shaban 13,14, Robert Booy 1,2 and Harunor Rashid 1,2**


Received: 14 September 2020; Accepted: 14 October 2020; Published: 16 October 2020

**Abstract:** This study examined Hajj pilgrims' knowledge and reported practice of hand hygiene. In Hajj 2019, a cross-sectional survey was undertaken in Mina, Makkah, Saudi Arabia, of domestic Saudi pilgrims aged ≥18 years by using a self-administered Arabic questionnaire that captured data on pilgrims' socio-demographics, hand hygiene knowledge, and reported practices of hand cleaning following certain actions. A total of 348 respondents aged 18 to 63 (median 32) years completed the survey, of whom 200 (57.5%) were female. The mean (±standard deviation (SD)) hand hygiene knowledge score was 6.7 (±SD 1.9). Two hundred and seventy one (77.9%) and 286 (82.2%) of respondents correctly identified that hand hygiene can prevent respiratory and gastrointestinal infections respectively, but 146 (42%) were not aware that it prevents hand-foot-mouth disease. Eighty-eight (25.3%) respondents erroneously reported that hand hygiene prevents HIV. Washing hands with water and soap was the most preferred method practiced before a meal (67.5% (235/348)), after a meal (80.2% (279/348)), after toilet action (81.6% (284/348)), when hands were visibly

soiled (86.2% (300/348)), and after waste disposal (61.5% (214/348)). Hajj pilgrims demonstrated a good knowledge and practice of hand hygiene, but there are gaps that are vital to control outbreaks such as COVID-19.

**Keywords:** COVID-19; Hajj; hand hygiene; infection prevention and control; infectious disease; mass gathering

#### **1. Introduction**

COVID-19 pandemic has affecting about 38 million individuals with over one million deaths around the world (as of 13 October 2020) [1]. The disease is believed to transmit from human to human primarily via respiratory droplets, direct contact and indirect contact. Most mass gatherings (MGs), therefore, have been cancelled during this pandemic. MGs are defined as the concentration of people at a specific location for a specific purpose over a set period of time and which has the potential to strain the planning and response resources of the country or community [2]. MGs are known to accelerate the progression of a pandemic. A MG of two million people in Mexico, the Iztapalapa Passion Play that took place in 5–11 April 2009 is believed to have accelerated the spread of the last pandemic caused by influenza A(H1N1)pdm09 [3]. Each year, Hajj pilgrimage to Makkah, in Saudi Arabia, attracts two to three million people from around the world making it one of the largest annual MGs. Respiratory tract infections are the leading illnesses during Hajj affecting 40–90% of pilgrims [4]. Such religious and other MGs pose a significant risk for the spread of infectious diseases, as currently the case with the global pandemic of COVID-19. Saudi Arabia has reported about 338 confirmed cases with about 5000 fatalities [1], and despite banning of Umrah (minor pilgrimage to holy cities in Saudi Arabia) and subsequently downscaling the Hajj of 2020, there have been clusters of COVID-19 in Makkah and Medina, the two important pilgrimage cities [5].

MG-related confirmed cases of COVID-19 have been reported in South East Asian countries like Malaysia [6], and South Korea [7]. In the Middle East, the virus spread from a religious MG in Qom, a Shi'ite holy city (120 km south of the capital Tehran), Iran [8]. Intense crowding during Hajj is highly likely to amplify the risk of transmission of COVID-19. Approximately a third of Hajj attendees are elderly or have pre-existing health conditions, rendering them highly vulnerable to severe form of disease and fatality from infection [9].

In the absence of a definitive preventive measure, non-pharmaceutical measures such as social distancing, isolation, quarantine, and hand hygiene remain the mainstay of infection prevention and control against respiratory infections including COVID-19 [10].

The Saudi Arabian Ministry of Health (MoH) recommends an array of preventive measures annually to minimize the risk of transmission of respiratory infections during Hajj season, including hand washing, respiratory hygiene, and vaccinations [9]. Despite this advice, research demonstrates that the uptake of preventive measures varies among pilgrims [11].

Hand hygiene was found to be the most favored infection preventive measure for Hajj attendees [11]. It is significantly associated with a reduction in self-reported respiratory infections including influenza-like illnesses (ILI) [12], frequency of sputum production, myalgia [13], and fever [14]. Use of an alcohol-based hand sanitizer significantly reduces *Streptococcus pneumoniae* detection in respiratory samples [15]. There is a paucity of focused research that has examined knowledge and practice of hand hygiene among domestic Hajj attendees. This study examined hand hygiene knowledge and reported behaviors among Saudi Hajj pilgrims in 2019 and attempts to inform policy for the other MGs amidst COVID-19.

#### **2. Materials and Methods**

A cross-sectional study using a paper-based anonymous survey was conducted among Saudi pilgrims aged ≥18 years who attended Hajj in 2019 in Mina tent city, Greater Makkah, Saudi Arabia, a place where pilgrims spend at least four nights during Hajj. A convenient sampling strategy was used to recruit participants. The data collectors went to Mina and randomly approached the nearest two domestic tour groups (Hamlahs) who agreed to cooperate with the study. From these selected Hamlahs the sample was drawn by randomly asking pilgrims to participate in the study.

This paper-based self-administered anonymous survey was conducted in Arabic. Initially, a survey questionnaire in English was drafted using some exemplary questions used in published surveys [16,17]. Two public health researchers and one epidemiologist translated the questionnaire to Arabic independently. Subsequently, two professional translators performed backward translation separately (who have not seen the original survey or material). The survey underwent pilot testing via a focus group of eight respondents to discuss and answer the survey to ensure readability, personal interpretation of individual question and solving any problems in answering the questions. Following revision, the final version was prepared by the authors that addressed grammatical discrepancies.

The questionnaire consisted of three parts. Part 1 collected non-identifying participant sociodemographic data. Part 2 collected data about the participant's knowledge of hand hygiene using true/false questions. Additionally, there were questions on common myths and fallacies of hand hygiene reported in the literature, such as the misconceptions that hands should be held under water while lathering with soap and the adequate time used for hands rubbing before rinsing. This was assessed using a Likert scale that uses scoring from 0 to 12, with a higher score indicating considerable knowledge level on hand hygiene and a lower score indicating insufficient knowledge. Part 3 comprised of items related to self-reported hand washing behavior. Respondents were asked whether they washed their hands, and by what methods, in different situations during their Hajj journey. These included hand washing before and after eating, after using toilet, after caring a sick person, when hands are visibly dirty, after disposal of a garbage bag, after sneezing or coughing, and after handshaking.

Seven senior medical students (four males and three females) were selected as volunteers and trained as data collectors. The volunteers approached and explained the study purpose and methodology to domestic Saudi Hajj pilgrims residing in camps in Mina on 11th and 12th of August 2019. Pilgrims who agreed to participate were then given the questionnaires to complete, and respondents' queries, if any, were answered. This being an anonymous survey, no signed consent was obtained, and respondents' completion of the survey was considered as their implied consent. Ethics approval was obtained from King Abdullah Medical City, Makkah, Saudi Arabia (IRB ref 19-558).

To ensure correct and uniform entry of data, the collected data from hard copy questionnaires were entered into an electronic form using the Google Forms software (Google LLC, Mountain View, CA, USA) (https://forms.gle/syQt5ouVzJ5usr318). Subsequently, all the data were exported to a master Excel spreadsheet (Microsoft Office 356, version 2002, Redmond, WA, USA) for cleaning and coding before importing to Statistical Package for Social Sciences (SPSS) software (IBM SPSS Statistics for Windows, version 25.0, IBM Corp, Armonk, NY, USA). Descriptive statistics for socio-demographic characteristics, hand hygiene knowledge level, and hand hygiene practices of the respondents were reported. Where appropriate the difference between categorical variables was examined using the chi-squared test, and independent t-test was used to compare the gender differences in the knowledge score on hand hygiene. Binary logistic regression, using the backward Wald method, controlling for factors, such as age, gender, chronic medical conditions, educational level, employment status and the number of times respondents attended Hajj, was used to investigate variables related to hand hygiene knowledge and practices. Previous researchers found that at least 60% of respondents were practicing hand hygiene at Hajj; considering an error margin of 5% to be acceptable for this anonymous survey, a sample of 370 respondents was considered sufficient for this study.

#### **3. Results**

Volunteers approached and invited 380 pilgrims to participate in the study, and 348 (91.6%) agreed. The median age of respondents was 32 (range 18–63) years, 200 (57.5%) were female. Of all 348 respondents, 208 (59.8%) had a bachelor's degree or above, 108 (51.7%) were employed, and 43 (12.4%) reported having at least one chronic disease. Just over three-quarters (270, 77.6%) of the respondents reported attending Hajj that year for the first time, with the rest (78, 22.4%) reporting attending Hajj previously at least once (Table 1).


**Table 1.** Demographic characteristics of respondents (N = 348).

Of the 348 respondents, there were 230 (66.3%) who reported being aware of the annual Saudi MoH health recommendations for Hajj travelers issued, 262 (75.5%) who reported seeking some form of health advice before Hajj journey, 286 (82.2%) reported receiving the compulsory meningococcal vaccine, and 288 (82.8%) reported receiving other recommended vaccines (Table 2).

With respect to knowledge about hand hygiene, the mean (±standard deviation (SD)) of total scores (0 to 12) was 6.7 (±1.9). Less than half (155, 44.5%) of the respondents had a low knowledge score (defined as total score of ≤6), over half (175, 50.3%) had a medium score (defined as total score of between 7 and 9), and the rest (18, 5.2%) had a high score (defined as total score of ≥10). In multivariate logistic regression analysis, there was no significant association between the level of hand hygiene knowledge and possible factors, including gender, age, having chronic diseases, number of Hajj times, education, and employment status (all *p* values > 0.05). Nonetheless, both gender and employment status showed a near statistical significance (odds ratio (OR) = 1.73, 95% CI = 0.98–3.07, *p* = 0.06 and OR = 1.76, 95% CI = 0.97–3.16, *p* = 0.06, respectively) with females and employed respondents having higher knowledge level compared to males and unemployed individuals. The results of the respondents' level of hand hygiene are detailed in Table 3.


**Table 2.** Awareness of Saudi Arabian Ministry of Health (MoH) recommendations, pre-Hajj health advice, and vaccination status (N = 348).

**Table 3.** Hand hygiene knowledge level among respondents (N = 348).




**§** Correct answer.

Table 4 summarizes the results of whether pilgrims practiced hand hygiene or not and by what methods in different situations during Hajj. Except for cleaning hands following handshakes, which was reported by just over half (177, 51.9%) respondents, an overwhelming majority of respondents reported cleaning their hands following other tasks. Hand washing using water and soap was the most commonly reported hand hygiene method among pilgrims across all situations. A small number (58, 16.7%) of the respondents reported barriers to using hand hygiene during Hajj season, notably unavailability of soap and hand rub (60.5% (31/58)), limited access to washrooms (23.3% (18/58)) and intense crowding (16.3% (14/58)).



#### **4. Discussion**

This study explored hand hygiene knowledge and reported practices of domestic Saudi Hajj pilgrims. There is a paucity of research that has examined hand hygiene knowledge among Hajj pilgrims. In this study the pilgrims had a moderate knowledge of hand hygiene (6.7 ± 1.9). Most respondents had an accurate knowledge of the protective role of hand hygiene against common infectious diseases such as respiratory and gastrointestinal infections, but some were not aware of its role against some less common but nonetheless important infections. Concerningly, about 40% of respondents were not aware that hand hygiene can prevent hand-foot-mouth disease for which hand hygiene is strictly advised, and a quarter of respondents mistakenly thought hand hygiene prevented HIV infection. Pilgrims' knowledge also varied for responses pertaining to questions relating to common myths surrounding hand hygiene and knowledge on correct hand hygiene procedure. For instance, half of the respondents reported that persistent hand washing lowers immunity, half thought that temperature of the water makes a difference in terms of the cleansing effect of hand washing, a third did not know that hands should not be placed under water while lathering, about 58% erroneously thought rubbing hands just for 10 s is enough to ensure disinfection while it should be 20 s, and about a third thought 40% alcohol is sufficient for disinfecting hands whereas the correct answer should be minimum 60% alcohol [10].

A study conducted among Malaysian pilgrims during the 2018 Hajj showed 87.1% pilgrims knew that washing one's hands with hand sanitizers can protect one from flu-like illness, which compares with only 77.9% pilgrims in our study knowing the role of hand hygiene against flu/cough/ILI [18]. The lower proportion in our study could be explained by the fact that foreign pilgrims are generally better informed and better prepared for Hajj travel since health authorities in their countries of origin are mandated to ensure health advice to pilgrims on communicable diseases prompting months of preparation including attendance at pre-travel health seminar (usually more than once) before embarking on Hajj journey [9]. It is also encouraging to see that more domestic pilgrims sought pre-Hajj advice in the present study compared to the previous year (three-quarters versus half) [19]. In this study, there was no significant difference in knowledge level by gender or age as was found in other studies involving Saudi healthcare workers and trainees [20]. It is unsurprising that some pilgrims lacked knowledge in some more specialist themes like alcohol concentration needs to be in disinfectants, duration of time required for hand rubbing, prohibition of placing hands under water while lathering and insignificance of water temperature, yet the pilgrims seem to have similar or even better knowledge in some domains compared to community dwellers in another developed country in Asia [17].

Hand washing with soap and water was the most common type of hand cleaning reportedly used by the study respondents in almost all the situations followed by alcohol hand rubbing. The results of this study are consistent with, and corroborate, the findings of other studies, including a systematic review, which found among Hajj pilgrims hand washing with soap was more popular than hand gel or sanitizers [18,21]. In contrast, a study explored domestic pilgrims' uptake of health preventive measures during the peak Hajj days found the proportion of respondents washing their hands with soap and cleaning hands with hand sanitizers was same (65%); however, pilgrims who were concerned about food poisoning were more likely to clean their hands with hand sanitizers (adjusted OR 2.5, 95% CI 1.1–5.4) indicating pilgrims' degree of concern may dictate the mode of hand hygiene [19].

The results of the present study also showed a relatively poor hand hygiene behavior after touching a patient with only 39.7% washing hands with soap–water and 31.9% using alcoholic hand rub, after sneezing and coughing (respectively 25.6% and 19.5%) and following handshakes (respectively 19.5% and 18.1%). Similarly, low compliance with hand hygiene following these actions in previous studies, for instance 15% Australian pilgrims washed hands after touching a patient while at Hajj, despite the fact that 86% made an intention before Hajj to wash hands after touching an ill person, indicating there were practical issues that barred them [22], e.g., unavailability of soap and hand rub, limited access to washrooms and intense crowding reported as barriers to hand hygiene in this study. Another study conducted among members of public across Gulf countries showed that only 39% individuals washed their hands with soap after handshakes which may indicate that in a non-epidemic setting most people

would not wash hands following handshake [23]. Regardless of what products are being used by pilgrims, hand hygiene in general has been proven to be an effective measure against respiratory infections at Hajj [12–14] and is practiced by pilgrims from different nationalities [18,19].

The patchy knowledge gap and non-compliance on certain occasions warrant improvement. This is indicated by the findings from this and a previous study that showed pilgrims with a university-level education had a higher hand hygiene compliance compared to those with a lower education, and several other studies reporting lack of awareness as an important hindrance to hand hygiene, meaning education may improve the hand hygiene uptake [24]. Through a pre- and post-intervention survey conducted during the Hajj 2011, Turkestani and colleagues showed that direct health education to pilgrims is effective in improving hand hygiene compliance rate from 79.1% to 95.5% [25]. During a pandemic era, such as the current COVID-19 outburst, intensive pre-travel health education perhaps through a certification program following a short course on hygiene may be made compulsory for all pilgrims. Tour operators may conduct the course and should have, as a pre-requisite of running Hajj tours, more advanced knowledge of hygiene, health, and safety. This can be buttressed by direct health education and a random quick knowledge test at the points of entries supplemented by multi- lingual health messages on billboard with graphical illustration on how to perform hand hygiene, map a direction of hand hygiene facilities and resources. Effective pandemic health messaging during the Hajj 2009 was associated with higher compliance with protective measures and with shorter duration of respiratory illnesses [12]. Furthermore, giving advice by Islamic scholars about the importance of alcohol- based hand rubs use and reinforce how this practice does not harm pilgrims could potentially eliminate taboos surrounding the use of alcohol-based hygienic products and in turn enhance compliance [26].

Although a small number of respondents reported some barriers in practicing hand hygiene during Hajj such as unavailability of soap and hand rub, limited access to washrooms, and intense crowding, solutions, for example, providing supplementary hand hygiene products to pilgrims, could potentially increase the uptake. However, in Hajj setting, such improvements are not always feasible; therefore, pilgrims are encouraged to carry their own personal hygiene products.

Considering the continuance of the COVID-19 pandemic and its risks of spreading in mass gatherings, and the increase in average infections globally, the Saudi Government decided to downscale Hajj for this year 2020 allowing only a thousand local and resident foreigners perform the pilgrimage [27].

This study had some limitations. Firstly, the survey was conducted only among domestic Saudi pilgrims who unlike international pilgrims bypass many vicissitudes of travel hence these findings may not be generalizable. Secondly, the reported barriers were not qualitatively gauzed, and finally, being anecdotal in nature some data (e.g., vaccination history) could be at risk of recall bias. These limitations can be addressed by a mixed-method study involving an extended sample from multiple nationalities with different health, education and cultural backgrounds.

#### **5. Conclusions**

There is a paucity of research that has examined infection prevention and control measures in MGs. Hand hygiene was generally acceptable among domestic Saudi pilgrims but there were variable knowledge gaps in some aspects that may be improved by intensive health education and awareness-raising strategies. Hajj pilgrims demonstrated a good knowledge and reported practice of hand hygiene, although there were some gaps in their key areas that are vital to containing and mitigating outbreaks, particularly in the context of MGs and the current global COVID-19 pandemic.

**Author Contributions:** Conceptualization: H.M., A.A. (Amani Alqahtani), and H.R.; methodology: H.M., A.A. (Amani Alqahtani) and H.R.; validation: H.M., A.A. (Amani Alqahtani) and O.B.; formal analysis: H.M. and A.A. (Amani Alqahtani); investigation: O.B., A.A. (Amjad Alemam), M.A., I.G., H.A., K.A., L.F., L.D. and S.A.; data curation: O.B. and A.A. (Amjad Alemam), M.A., I.G., H.A., K.A., L.F., L.D. and S.A.; writing—original draft preparation: H.M., A.A. (Amjad Alemam), M.A., I.G., H.A., K.A., L.F., L.D. and S.A.; writing—review and editing: A.A. (Amani Alqahtani), H.R., R.S. and R.B.; supervision: R.S., R.B. and H.R.; project administration: H.M., A.A. (Amani Alqahtani) and H.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


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## *Article* **Meningococcal Vaccine for Hajj Pilgrims: Compliance, Predictors, and Barriers**

**Al-Mamoon Badahdah 1,2,3,\*, Fatimah Alghabban <sup>4</sup> , Wajd Falemban <sup>4</sup> , Abdullah Albishri <sup>3</sup> , Gouri Rani Banik <sup>1</sup> , Tariq Alhawassi <sup>5</sup> , Hatem Abuelizz <sup>5</sup> , Marwan A. Bakarman <sup>3</sup> , Ameneh Khatami 2,6 , Robert Booy 1,2,7 and Harunor Rashid 1,2,7**


Received: 28 August 2019; Accepted: 9 October 2019; Published: 15 October 2019

**Abstract:** Background: Major intercontinental outbreaks of invasive meningococcal disease associated with the Hajj occurred in 1987, 2000, and 2001. Mandatory meningococcal vaccination for all pilgrims against serogroups A and C and, subsequently, A, C, W, and Y controlled the epidemics. Overseas pilgrims show excellent adherence to the policy; however, vaccine uptake among domestic pilgrims is suboptimal. This survey aimed to evaluate meningococcal vaccine uptake among Hajj pilgrims and to identify key factors affecting this. Methods: An anonymous cross-sectional survey was conducted among pilgrims in Greater Makkah during the Hajj in 2017–2018. Data on socio-demographic characteristics, vaccination status, cost of vaccination, and reasons behind non-receipt of the vaccine were collected. Results: A total of 509 respondents aged 13 to 82 (median 33.8) years participated in the survey: 86% male, 85% domestic pilgrims. Only 389/476 (81.7%) confirmed their meningococcal vaccination status; 64 individuals (13.4%), all domestic pilgrims, did not receive the vaccine, and 23 (4.8%) were unsure. Among overseas pilgrims, 93.5% certainly received the vaccine (6.5% were unsure) compared to 80.9% of domestic pilgrims (*p* < 0.01). Being employed and having a tertiary qualification were significant predictors of vaccination adherence (odds ratio (OR) = 2.2, 95% confidence interval (CI) = 1.3–3.8, *p* < 0.01; and OR = 1.7, CI = 1–2.5, *p* < 0.05, respectively). Those who obtained pre-Hajj health advice were more than three times as likely to be vaccinated than those who did not (OR = 3.3, CI = 1.9–5.9, *p* < 0.001). Lack of awareness (63.2%, 36/57) and lack of time (15.8%, 9/57) were the most common reasons reported for non-receipt of vaccine. Conclusion: Many domestic pilgrims missed the compulsory meningococcal vaccine; in this regard, lack of awareness is a key barrier. Being an overseas pilgrim (or living at a distance from Makkah), receipt of pre-Hajj health advice, and employment were predictors of greater compliance with the vaccination policy. Opportunities remain to reduce the policy–practice gap among domestic pilgrims.

**Keywords:** Hajj; meningococcal disease; vaccine uptake; pre-travel health advice

#### **1. Introduction**

Hajj is a large annual mass gathering that attracts more than two million Muslims from around the world to congregate within confined areas in Makkah, Saudi Arabia. A highly crowded and congested environment during Hajj amplifies risks associated with mass gatherings, including transmission of respiratory organisms, notably *Neisseria meningitidis* [1,2].

*Neisseria meningitidis* is associated with a substantially high rate of carriage (up to 86%) in crowded and closed populations, which resulted in large intercontinental outbreaks of invasive meningococcal disease during Hajj [3]. Following the Hajj in 1987, an intercontinental Hajj-related outbreak of meningococcal serogroup A (MenA) disease led to approximately 2000 cases [4], and its subsequent introduction into the African meningitis belt affected around 70,000 people [5]. Furthermore, in 2000 to 2001, a large outbreak of meningococcal disease resulted in at least 47 deaths, including 11 deaths in the United Kingdom, and affected no fewer than 2400 people in several countries throughout Asia, Africa, Europe, and North America. Serogroup W (MenW; a serogroup that was not previously known to cause large epidemics) sequence type 11 was responsible for over half of those cases [4,6].

Mandatory bivalent (serogroups A and C) meningococcal vaccination for all pilgrims from 1987 brought the disease under control during the Hajj for more than a decade [6,7]. Switching the vaccination policy to the quadrivalent (serogroups A, C, W, and Y) meningococcal (MenACWY) polysaccharide vaccine in 2002, coupled with chemoprophylaxis at the port of entry for pilgrims arriving from the African meningitis belt, again brought the subsequent epidemics under control [8]. Since then, no further Hajj-related meningococcal outbreaks occurred [6]. The mandatory vaccination policy also applies to residents of Hajj zones and to personnel who serve pilgrims during the Hajj, including healthcare workers (HCWs) (Table 1) [1,9].


**Table 1.** Current preventive measures mandated by the Saudi Arabian government to control meningococcal disease during Hajj.

MenACWY; quadrivalent meningococcal serogroup A, C, Y, and W. \* A minor pilgrimage to Makkah outside of the Hajj season. \*\* Requirements for Hajj and Umra entry visa, and for Hajj permit for domestic pilgrims. \*\*\* Including individuals working at points of entry or in direct contact with pilgrims.

Monitoring the annual number of Hajj visas and mandating the vaccine as a prerequisite for the visa application both limited the numbers of overseas pilgrims and improved vaccination rates. For instance, reports on vaccine uptake among overseas pilgrims since 2006 showed a compliance of no less than 96% and reaching up to 100% [10–14]; however, concerns remain among this group of pilgrims, including the receipt of inappropriate vaccines and, due to the limited access to vaccines (including cost), the use of fraudulent vaccination certificates [11,15,16].

Since 2003, Saudi citizens and other expatriate residents in Saudi Arabia who intend to perform Hajj must apply for a Hajj permit with a MenACWY vaccine receipt stipulated as a requirement. Despite this, unauthorized domestic pilgrims often sometimes enter Hajj sites without a permit and

without formally registering with an official Hajj tour group. Additionally, despite being enforced and freely offered, the vaccine coverage was found to be very low (64%) in 2006 in the only published work reporting vaccine uptake among domestic pilgrims [12]. The rate was also unsatisfactory among domestic HCWs (ranging from 51.7% to 84.7%) in several studies conducted between 2009 and 2018 [17–20]. In recent years, the enforcement of the Hajj permit requirement by rigorous procedures at points of entry into Makkah reduced the number and proportion of domestic pilgrims (from 1.4 million (45%) in 2012 to 600,000 (26%) in 2018) [21]. However, there is no recent study assessing the uptake of meningococcal vaccines among these pilgrims. To this end, a survey was undertaken to evaluate the coverage of MenACWY vaccines among Hajj pilgrims and to identify the key predictors and barriers affecting their uptake, particularly among domestic pilgrims, which was not assessed in previous studies.

#### **2. Materials and Methods**

An anonymous cross-sectional survey was distributed among domestic pilgrims present in Mina, a tent city, and a main Hajj site on the outskirts of Makkah, and among overseas pilgrims who were staying in Aziziyah (before moving to tents in Mina), a borough of Makkah, adjacent to Mina, during the Hajj seasons of 2017 and 2018.

#### *2.1. Participant Recruitment*

Overseas and official domestic pilgrims were eligible to participate; all other non-pilgrims were excluded. In order to recruit a representative sample of both domestic and international pilgrims, the research team approached domestic pilgrims in their camps in Mina, and overseas pilgrims living in hotels/serviced apartments in Aziziyah. The research team (composed of research doctors and trained volunteer allied health or medical students) randomly approached tour operators to access their tent camps or housing and to invite pilgrims to the study. The research team, after obtaining permission from the tour group leaders, explained the study to their pilgrims, answered any queries they had, and invited them to participate. Participation depended primarily on the cooperation of the tour group leader, and then the pilgrim's willingness to participate.

No identifiable personal data were collected, and respondents' completion of the survey was considered implied consent. This study was reviewed and approved by the Institutional Review Board of King Saud University College of Medicine, Riyadh, Saudi Arabia (E-17-2534).

#### *2.2. Survey Design*

The survey was designed and reviewed by experts in the field of Hajj and vaccine-preventable diseases. The questionnaire collected data on socio-demographic characteristics (such as age, gender, educational level, and employment status), as well as uptake of meningococcal vaccines as a preparation for Hajj and reasons behind non-receipt of the vaccine in such cases. It also evaluated if this was the participant's first time to the Hajj, whether the vaccine was freely offered, and the receipt of pre-Hajj health advice. The survey was primarily in English, with Arabic translations available for those who preferred to complete the survey in Arabic. Survey responses were collected using a printed or web-based form securely hosted in WufooTM (SurveyMonkey Inc., San Mateo, CA, USA). Written responses were entered into the web-based form, and all data were subsequently exported to a Microsoft ExcelTM (Microsoft Corp., Redmond, WA, USA) spreadsheet for analysis.

#### *2.3. Statistical Methods*

The proportion of participants responding to each question was reported. To measure the association between predictors and vaccine uptake, odds ratios (OR) with 95% confidence intervals (95% CI) based on the risk estimate statistics were calculated. Pearson's chi-squared test was used to compare categorical variables and determine associations and correlations. For questions evaluating sources of pre-Hajj health advice and reasons for non-receipt of the vaccine, one sample nonparametric test (Jeffreys interval) was used to report the proportion of participants providing each response and the 95% CI for the point estimate.

All those who declared previous receipt of the vaccine, regardless of the year of vaccination, were considered as vaccinated; further analysis was done to determine the adherence to the vaccine policy time window. Participants who were unsure about their vaccination history were excluded from the analysis in the OR calculation. A *p*-value ≤ 0.05 was considered statistically significant. The statistical analysis was performed using the Statistical Package for Social Sciences (SPSSTM) for WindowsTM v.25.0 (IBM Corp., Armonk, NY, USA).

#### **3. Results**

#### *3.1. Participant Characteristics*

In total, 513 pilgrims agreed to participate in the study, of whom 509 completed the survey; the remaining four submitted blank forms and, hence, were excluded from the denominator. Only 444 respondents declared their age, ranging from 13 to 82 years (mean 36, SD ±12.6). Males comprised 86% of the sample, and local pilgrims accounted for 85%. Table 2 summarizes the demographic characteristics of the surveyed participants.

#### *3.2. Meningococcal Vaccine Uptake*

Of the 476 participants who declared their vaccination status, only 389 (81.7%) confirmed receipt of a meningococcal vaccine; 64 (13.4%), all domestic pilgrims, did not receive the vaccine, and 23 (4.8%) were unsure about their vaccination status. Almost all (93.5% (58/62)) overseas pilgrims declared receipt of the vaccine, although four (6.5%) were unsure, compared with 80.9% (321/397) of domestic pilgrims who received the vaccine (*p* < 0.01), 61/397 (15.3%) who did not, and 15/397 (3.8%) who were unsure (Table 3). Employed participants were twice as likely to be vaccinated as those who were not employed, and those who received pre-Hajj health advice from any source, and those with a tertiary qualification had a higher vaccination uptake rate. Among domestic pilgrims, those from Makkah province were almost three times more likely to miss out on the vaccine compared to those from other provinces.


*Trop. Med. Infect. Dis.* **2019**, *4*, x FOR PEER REVIEW 8 of 13

 1 time previously 215/500 (43) 197/409 (48.2) 11/71 (15.5) SD—standard deviation. \* The total number of respondents with complete information for each individual variable. \*\* Twenty participants with unknown allocation status (overseas or domestic). \*\*\* Statistically significant. OR, odds ratio; 95% CI, 95% confidence interval; *p*, *p-*value; ref, reference value. \* Total number of respondents with known source of payment and complete information for each individual variable. ¶ Holders of any visa other than a Hajj visa were officially treated as domestic pilgrims. } Year 10 equivalent; § year 12 equivalent.

First time 285/500 (57) 212/409 (51.8) 60/71 (84.5) < 0.001 \*\*\*

>

Yes 32/246 (13) 1.0 (ref)

No 21/108 (19.4) 1.6 (0.9–3) 0.12

Includes all participants with known source of payment. § Statistically significant.

*3.6. Receipt of Pre-Hajj Advice* 

Only 19.4% (98/504) of participants received pre-Hajj health advice from one or more "professional" sources, including general practitioners or a specialized travel clinic; 61% (309/504) received advice from "non-professional" sources, and 19% (97/504) did not receive any advice (Figure 2). Notably, overseas pilgrims (64%) were more likely to receive advice from professional

sources than domestic pilgrims (16%; OR = 9.6, 95% CI = 5.3–17.3, *p* < 0.001).


*Trop. Med. Infect. Dis.* **2019**, *4*, x FOR PEER REVIEW 8 of 13

 South Africa 3/20 (15) Other 9/27 (33.3)

**Hajj attendance** 

≥ 1 time previously 13/165 (7.9) 1.0 (ref)

First time 41/193 (21.2) 3.2 (1.6–6.1) < 0.001 §

**Tertiary qualification** 

**Employed**

Yes 31/246 (12.6) 1.0 (ref)

No 22/112 (19.6) 1.7 (0.9–3.1) 0.09


and complete information for each individual variable. \*\* For OR calculation, responses with "unsure" for vaccination status were excluded.

Includes all participants with vaccination

Includes all participants with known source of payment. § Statistically significant.

status. § Statistically significant.

*3.6. Receipt of Pre-Hajj Advice* 

Only 19.4% (98/504) of participants received pre-Hajj health advice from one or more "professional" sources, including general practitioners or a specialized travel clinic; 61% (309/504) received advice from "non-professional" sources, and 19% (97/504) did not receive any advice (Figure 2). Notably, overseas pilgrims (64%) were more likely to receive advice from professional

sources than domestic pilgrims (16%; OR = 9.6, 95% CI = 5.3–17.3, *p* < 0.001).

#### *3.3. Participant Adherence to Vaccination Policy 3.3. Participant Adherence to Vaccination Policy*

Overall, among the 389 vaccinated individuals, 329 (84.6%) received the vaccine within the last three years, 12 (3.1%) received it over three years prior to Hajj attendance, and 48 (11.9%) did not declare the year of vaccination. Thus, 20.5% (70/341) of domestic pilgrims failed to confirm their adherence to the complete vaccination policy (either did not receive the vaccine at all, received it over three years prior, or were unsure about their vaccination status). This translates to an almost seven-fold increased risk of non-compliance with the vaccine policy compared to overseas pilgrims (OR = 6.8, 95% CI = 1.6–28.8), *p* < 0.01). Lack of awareness that the vaccine is a mandatory requirement (63.2%, 36/57) was the main reason given for not receiving the vaccine (Figure 1). Overall, among the 389 vaccinated individuals, 329 (84.6%) received the vaccine within the last three years, 12 (3.1%) received it over three years prior to Hajj attendance, and 48 (11.9%) did not declare the year of vaccination. Thus, 20.5% (70/341) of domestic pilgrims failed to confirm their adherence to the complete vaccination policy (either did not receive the vaccine at all, received it over three years prior, or were unsure about their vaccination status). This translates to an almost seven-fold increased risk of non-compliance with the vaccine policy compared to overseas pilgrims (OR = 6.8, 95% CI = 1.6–28.8), *p* < 0.01). Lack of awareness that the vaccine is a mandatory requirement (63.2%, 36/57) was the main reason given for not receiving the vaccine (Figure 1).

**Figure 1.** Reasons for non-receipt of meningococcal vaccine among unvaccinated domestic pilgrims: proportion of participants providing each reason with the 95% confidence interval for the point **Figure 1.** Reasons for non-receipt of meningococcal vaccine among unvaccinated domestic pilgrims: proportion of participants providing each reason with the 95% confidence interval for the point estimate.

#### estimate. *3.4. Vaccination Venues*

*3.4. Vaccination Venues* Domestic pilgrims were mainly vaccinated at primary health care centers (79.3%), while Domestic pilgrims were mainly vaccinated at primary health care centers (79.3%), while overseas pilgrims mostly visited hospitals or travel clinics (70.3%).

overseas pilgrims mostly visited hospitals or travel clinics (70.3%).

Male 38/302 (12.6) 1.0 (ref)

Domestic 30/307 (9.8) 1.0 (ref)

Pakistan 17/17 (100)

#### *3.5. Cost of Vaccination*

*3.5. Cost of Vaccination* Overall, 55 (15.1%) participants paid for the vaccine. Overseas pilgrims, women, and those who attended Hajj for the first time were significantly more likely to pay for the vaccine than domestic pilgrims, men, or those who attended Hajj previously (Table 4). Overall, 55 (15.1%) participants paid for the vaccine. Overseas pilgrims, women, and those who attended Hajj for the first time were significantly more likely to pay for the vaccine than domestic pilgrims, men, or those who attended Hajj previously (Table 4).

#### *3.6. Receipt of Pre-Hajj Advice*

**Gender**

**Origin**

**Table 4.** Covering the cost of vaccination. **Characteristics Proportion of Participants Who Paid for the Vaccine** *n*/*N* \* (%) OR (95% CI) *p* **All** All participants ¶ 55/364 (15.1) Only 19.4% (98/504) of participants received pre-Hajj health advice from one or more "professional" sources, including general practitioners or a specialized travel clinic; 61% (309/504) received advice from "non-professional" sources, and 19% (97/504) did not receive any advice (Figure 2). Notably, overseas pilgrims (64%) were more likely to receive advice from professional sources than domestic pilgrims (16%; OR = 9.6, 95% CI = 5.3–17.3, *p* < 0.001).

Female 16/49 (32.7) 3.4 (1.7–6.7) < 0.001 §

Overseas 23/48 (47.9) 8.5 (4.3–16.7) < 0.001 §

*Trop. Med. Infect. Dis.* **2019**, *4*, x FOR PEER REVIEW 8 of 13

 South Africa 3/20 (15) Other 9/27 (33.3)

≥ 1 time previously 13/165 (7.9) 1.0 (ref)

Yes 31/246 (12.6) 1.0 (ref)

No 22/112 (19.6) 1.7 (0.9–3.1) 0.09

**Hajj attendance** 

**Employed**

**Tertiary qualification** 


**Table 4.** Covering the cost of vaccination.

OR, odds ratio; 95% CI, 95% confidence interval; *p*, *p*-value; ref, reference value. \* Total number of respondents with known source of payment and complete information for each individual variable. OR, odds ratio; 95% CI, 95% confidence interval; *p*, *p-*value; ref, reference value. \* Total number of respondents with known source of payment and complete information for each individual variable. ¶ Includes all participants with known source of payment. § Statistically significant. Includes all participants with known source of payment. § *Trop. Med. Infect. Dis.* **2019** Statistically significant. , *4*, x FOR PEER REVIEW 9 of 13

**Figure 2.** Sources of pre-Hajj health advice among participants who received such advice: proportion of participants providing each response with the 95% confidence interval for the point estimate. **Figure 2.** Sources of pre-Hajj health advice among participants who received such advice: proportion of participants providing each response with the 95% confidence interval for the point estimate.

#### **4. Discussion 4. Discussion**

general population, as well as HCWs.

The key finding of this study is that around one-sixth of domestic Hajj pilgrims failed to receive the compulsory MenACWY vaccine in recent years. Meningococcal vaccination is a visa prerequisite for international pilgrims; thus, a high coverage among overseas pilgrims was expected and demonstrated (93.5%). In this regard, the findings of this study are consistent with previous reports. Compliance among overseas pilgrims ranged from 96% to 98% between 2006 and 2010 [13], and two recent studies conducted at King Abdul Aziz International Airport, among 796 and 5235 arriving overseas pilgrims in 2013 and 2014, revealed uptake rates of 98.2% and 100%, respectively [10,11]. The key finding of this study is that around one-sixth of domestic Hajj pilgrims failed to receive the compulsory MenACWY vaccine in recent years. Meningococcal vaccination is a visa prerequisite for international pilgrims; thus, a high coverage among overseas pilgrims was expected and demonstrated (93.5%). In this regard, the findings of this study are consistent with previous reports. Compliance among overseas pilgrims ranged from 96% to 98% between 2006 and 2010 [13], and two recent studies conducted at King Abdul Aziz International Airport, among 796 and 5235 arriving overseas pilgrims in 2013 and 2014, revealed uptake rates of 98.2% and 100%, respectively [10,11]. However, assessing

Several studies demonstrated suboptimal meningococcal vaccine coverage among local HCWs, which, at best, did not exceed 85% among highly vulnerable hospital emergency room HCWs in Madina in 2015 [19]. A similar rate (82.4%) was also reported among HCWs working in Mina and Arafat, principal Hajj zones in Makkah, in 2003 [17]. Other studies found uptake rates as low as

Longer distance of travel appears to act as a motivator for overseas pilgrims to better prepare for Hajj and to seek and follow health advice. This was also noted even among domestic participants in this survey. Similarly, in a previous vaccine uptake survey among domestic pilgrims, fewer pilgrims (50%) from Hajj zones (Makkah and Jeddah) were shown to be vaccinated against MenACWY than pilgrims from other regions in Saudi Arabia (71%) [12]. Moreover, pilgrims from Makkah city were found to have lower vaccination coverage against seasonal influenza than

67.1% and 76.1% among HCWs serving pilgrims in 2009 and 2018, respectively [18,20].

pilgrims from the rest of the country (adjusted OR = 0.52, 95% CI = 0.37–0.72, *p* < 0.001) [22].

However, assessing compliance to other measures of the vaccination policy among overseas

pilgrims who form nearly one-third of total attendees at Hajj each year is unacceptably low. Although the vaccine uptake identified in this survey (85%) is higher than that reported by El Bashir et al. during the Hajj in 2006 (64% among domestic pilgrims who attended the National Guard Clinics in Makkah [12]), it appears that the official regulation that mandates meningococcal vaccination as a prerequisite for a Hajj permit for locals is less effective than that applied to international pilgrims, and a significant number of domestic pilgrims are able to avoid vaccination. Ensuring no Hajj permit is granted unless a valid certificate is provided may improve the situation; however, it is possible that there are more prevailing factors involved, including education of the compliance to other measures of the vaccination policy among overseas pilgrims, such as type and timing of vaccination, is recommended [11,16].

Nevertheless, it is concerning that, despite regulatory efforts, vaccine uptake among local pilgrims who form nearly one-third of total attendees at Hajj each year is unacceptably low. Although the vaccine uptake identified in this survey (85%) is higher than that reported by El Bashir et al. during the Hajj in 2006 (64% among domestic pilgrims who attended the National Guard Clinics in Makkah [12]), it appears that the official regulation that mandates meningococcal vaccination as a prerequisite for a Hajj permit for locals is less effective than that applied to international pilgrims, and a significant number of domestic pilgrims are able to avoid vaccination. Ensuring no Hajj permit is granted unless a valid certificate is provided may improve the situation; however, it is possible that there are more prevailing factors involved, including education of the general population, as well as HCWs.

Several studies demonstrated suboptimal meningococcal vaccine coverage among local HCWs, which, at best, did not exceed 85% among highly vulnerable hospital emergency room HCWs in Madina in 2015 [19]. A similar rate (82.4%) was also reported among HCWs working in Mina and Arafat, principal Hajj zones in Makkah, in 2003 [17]. Other studies found uptake rates as low as 67.1% and 76.1% among HCWs serving pilgrims in 2009 and 2018, respectively [18,20].

Longer distance of travel appears to act as a motivator for overseas pilgrims to better prepare for Hajj and to seek and follow health advice. This was also noted even among domestic participants in this survey. Similarly, in a previous vaccine uptake survey among domestic pilgrims, fewer pilgrims (50%) from Hajj zones (Makkah and Jeddah) were shown to be vaccinated against MenACWY than pilgrims from other regions in Saudi Arabia (71%) [12]. Moreover, pilgrims from Makkah city were found to have lower vaccination coverage against seasonal influenza than pilgrims from the rest of the country (adjusted OR = 0.52, 95% CI = 0.37–0.72, *p* < 0.001) [22].

An important finding of this survey is that receiving pre-travel health advice, regardless of the source, substantially increased compliance with the vaccination policy. The majority of overseas pilgrims received "professional" pre-Hajj health advice, while locals tended to rely on "social" sources. However, receiving any pre-travel health advice, being employed, and having a tertiary qualification were each individually associated with greater compliance with the vaccination policy. Previous reports on uptake of other recommended vaccines at Hajj also indicated that receiving pre-travel health advice was a considerable motivator for receiving vaccinations against other diseases [14,23]. Furthermore, in a large survey among residents of Gulf Cooperation Council countries, doctors' advice was the leading motivator for receipt of influenza vaccine [24]. Worksite immunization was shown to be effective in facilitating influenza vaccine uptake in Saudi Arabia [25]. Similarly, some employed participants of this survey indicated receiving the meningococcal vaccine at or through their workplace. This may explain the higher vaccine uptake among employed participants compared with those who identified themselves as unemployed. Additionally, more educated pilgrims were more likely to receive the meningococcal vaccine than those with lower educational attainment. A cross-sectional study of Australian Hajj pilgrims also demonstrated that having a university education was associated with a higher likelihood of receiving recommended Hajj vaccines (OR = 3.4, 95% CI = 1.7–6.7, *p* = 0.01) [14]. Previous reports also described a higher rate of vaccine uptake in women preparing to be pilgrims [20,26,27]. The association observed in this survey was in the same direction, but the difference with men was not statistically significant, which may be due to the low proportion of women who participated in the survey.

Unvaccinated domestic pilgrims named several barriers to vaccination; lack of awareness that the vaccine is compulsory was the most commonly cited reason, followed by lack of time. Lack of awareness as a barrier to vaccination is consistent with pervious findings on meningococcal vaccine uptake during Hajj among local HCWs [19,20]. In fact, lack of knowledge was also highlighted in previous studies reporting uptake of other Hajj recommended vaccines such as influenza vaccine, for both Saudi [22] and international pilgrims (during the influenza A (H1N1) pandemic) [28]. Lack of awareness was also the main reason reported by Australian pilgrims in 2014 for not receiving

Hajj recommended vaccines [14]. Lack of time was also found to be a barrier to vaccination among emergency room HCWs in Madina [19] and was shown to be a more significant barrier to influenza vaccination among domestic male pilgrims compared to female pilgrims [22].

Surprisingly, a substantial minority of domestic pilgrims also reported having to pay for their vaccine, which in principle should be provided freely in major public primary healthcare facilities across the country. Unfortunately, the wording of the pre-defined questionnaire had limited ability to identify this as a barrier among domestic pilgrims.

New, highly immunogenic, conjugate vaccines are replacing the older polysaccharide vaccines in many developed countries, and they are increasingly being recommended for Hajj pilgrims. Conjugate vaccines are more effective in controlling the carriage of meningococci [29,30] but are considerably more expensive. Meningococcal serogroups that are not covered by the current quadrivalent vaccine were frequently isolated from throat swabs collected from pilgrims, namely, serogroups B and, less frequently, X [31–33]. A recent systematic review concluded that serogroup B dominated the carriage acquisition among Hajj pilgrims [32], and most carriers received the polysaccharide vaccine, which is not expected to reduce the carriage acquisition of serogroups contained in the vaccine [34,35]. The opportunity to prevent future outbreaks depends on an ongoing review of the current mandatory vaccination policy in view of these and future developments.

Promisingly, most of the participants received some pre-Hajj health advice, but the fact that 84% of vaccinated domestic pilgrims (who certainly had a pre-Hajj contact with health professionals) stated non-receipt of advice from a "professional" source deserves careful attention. This provides an important reminder to local health authorities to take advantage of the national Hajj immunization program as an opportunity for providing face-to-face pre-Hajj health education.

The strength of this survey is that it provides a snapshot regarding the current situation with uptake of the compulsory meningococcal vaccine among mainly domestic Hajj pilgrims, and, for the first time, it provides insight into some of the barriers to vaccination. However, since pilgrims are often too busy to complete forms, the small sample size and the submission of incomplete responses are key limitations of this survey. Additionally, the small number of unvaccinated participants limits the ability to draw reliable conclusions regarding the true role of specific barriers. Furthermore, the data are self-reported, and we had no way of validating vaccination histories; moreover, the questionnaire did not differentiate between conjugate and polysaccharide meningococcal vaccines. Finally, we considered all those who stated previous receipt of the vaccine as vaccinated; however, since some respondents did not state the year of vaccination, the true uptake rates may be lower than reported here. The inability to include "unauthorized" domestic pilgrims also adds to the potential overestimation of the true vaccine uptake rate among domestic pilgrims.

In conclusion, this survey demonstrates that many domestic pilgrims miss the compulsory meningococcal vaccine prior to attending Hajj. Overseas pilgrims appear to have good uptake of the vaccine, as expected from the mandatory vaccination for visa policy. Receipt of pre-travel health advice, regardless of the source, is a key motivator for vaccine uptake, and lack of awareness about the vaccination policy is an important barrier. Improving vaccine uptake likely requires system-wide strategies, such as reducing financial barriers and increasing the availability of vaccination centers, as well as greater education of the public, particularly targeting those who are intending to perform Hajj, regarding Hajj-related health risks and prevention strategies. Strategies to improve the ability of local HCW to proactively provide preventive pre-Hajj health advice are also needed. Additionally, the success of the mandatory vaccination policy that is applied to international pilgrims should be modeled to improve compliance with the domestic policy through more rigorous checks and measures. Ongoing evaluation of such strategies is required to monitor the true uptake of vaccines and other health-promoting behaviors among domestic (and international) pilgrims, so that appropriate public health responses can be made to evolving situations.

**Author Contributions:** Conceptualization, G.R.B., T.A., H.A., and H.R.; data curation, A.-M.B.; formal analysis, A.-M.B. and H.R.; project administration, H.R.; supervision, A.K., R.B., and H.R.; validation, A.-M.B., F.A., W.F., and A.A.; visualization, A.-M.B.; writing—original draft, A.-M.B., F.A., W.F., A.A., and A.K.; writing—review and editing, G.R.B., T.A., H.A., M.A.B., A.K., and H.R.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors wish to thank the volunteers of the Hajj Health Volunteering Program, the respondents, and their tour group operators for their participation/cooperation in this survey.

**Conflicts of Interest:** Professor Robert Booy receives funding from Baxter, CSL/Seqirus, GSK, Merck, Novartis, Pfizer, Roche, Romark, and Sanofi Pasteur for the conduct of sponsored research, travel to present at conferences, or consultancy work; all funding received is directed to research accounts at The Children's Hospital at Westmead. Dr Harunor Rashid receives fees from Pfizer, Novartis, and Sanofi Pasteur for consulting or serving on an advisory board. The other authors have no conflicts of interest to declare in relation to this manuscript.

#### **References**


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