**3. Results**

In total, 294 HCWs participated in this study. Among them, 164 (55.8%) were nurses, 114 (38.8%) medical doctors (MDs), 14 (4.8%) paramedical staff, 1 (0.3%) employee of the technical service, and 1 (0.3%) participant did not report his profession. Median age was 42 years (interquartile range: 22 to 66 years), and 103 (35%) of the participants were male. Participants' characteristics are shown in Table 1. The questionnaire used in this study is shown in Document S1.

In terms of the source of participants' information, 171 (69%) responded that the main information sources were academic journals and specialized COVID-19 websites, while 40 (16.1%) stated that their main source of information were the media. When asked about the causative agen<sup>t</sup> of COVID-19, 291 (99.3%) participants stated that it is a virus. Regarding the origin of the causative agen<sup>t</sup> of COVID-19, 199 (70.1%) stated it is a virus that occurred as a result of natural mutation in China, however, 76 (26.8%) answered it is a virus that was created in a Chinese laboratory. In terms of transmission, 210 (75.3%) of

the responders believe COVID-19 is transmitted through aerosol, while 62 (22.2%) believe it is transmitted through droplets. When asked about the most common symptoms of COVID-19, most HCWs (252 (92.3%)) replied the disease causes fever and respiratory symptoms (Figure 1).


Among the participants HCWs, 104 (35.5%) believe the preparedness of their hospital is high, 52 (17.7%) believe it is very high, while 91 (31.1%) believe it is adequate. The majority of the responders were not significantly afraid of developing COVID-19, 97 (33.1%) and 84 (28.7%) HCWs were moderately or slightly afraid, respectively, while the rates of fear of having a close relative developing COVID-19 were 91 (31%) and 66 (22.4%), respectively. The majority of the HCWs was slightly satisfied from the personal protective equipment

provided from their hospital, whereas, 89 (30.3%) and 79 (26.9%) were moderately and significantly satisfied, respectively (Figure 2).

**Table 1.** Participants' characteristics. NR: not reported; SD: standard deviation.


\$OZD\V **Figure 2.** Personal perceptions regarding COVID-19 and hand-wash practices of healthcare workers.

The vast majority (222, 76%) of the participants stated they always perform hand hygiene after contact with a patient, regardless of COVID-19 suspicion. On the other hand, 114 (40.7%) HCWs stated they do not always perform hand hygiene after contacting a surface or equipment in their workplace (Figure 2).

Regarding knowledge on disinfection and room ventilation guidance, 246 (85.4%) responded correctly regarding the reduction in infectivity in a room with active ventilation system, while 214 (74%) responded correctly regarding the reduction in infectivity by purely fresh air ventilation. When questioned on how much aeration of closed spaces contributes to prevention of SARS-CoV-2 hospital spread, 146 (49.7%) and 88 (29.9%) thought they contribute extremely, and significantly, respectively. When asked about the most effective method of HCWs protection against COVID-19, 149 (84.7%) answered the combination of appropriate use of surgical mask and appropriate application of hand hygiene yielded the maximum protection. Twelve responders (6.8%) believed that use of higher-protection masks (FFP2/FFP3) is most important (Figure 3).

Regarding the knowledge on hand washing 80 (47.9%) HCWs responded correctly for the appropriate practice. Notably, 46 (27.5%) responders stated that hands should only be washed when visibly dirty, and an alcoholic antiseptic solution should be used in other instances. Thirty six (21.6%) HCWs stated that hand hygiene with alcoholic antiseptics should be used in every occasion instead of hand washing. In total, 216 (73.5%) HCWs answered they know the five steps of hand hygiene and they applied them all whenever indicated, while 47 (16%) stated they know them but do not always perform them due to lack of time during their daily shifts. Female HCWs replied more often that they knew the five steps and that they always applied them compared to men. HCWs stated they were performing aerosol-producing activities in patients with possible COVID-19, 62 (32.3%) among them stated they are performing such acts with adequate preventive measures, 38 (19.8%) were performing such acts and were, also, trying to avoid them, while 49 (25.5%) were trying to avoid them most of the times (Figure 3).

When asked on the duration of isolation before returning to work in the case of COVID-19 acquisition (provided no immunosuppression and not working in a department with high-risk patients), 106 (36.6%) responded that the isolation should be 7 days, while 102 (35.2%) responded that it should be 14 days. A total of 75 (25.9%) HCWs mentioned that they were not aware, but they would consult the Hospital Infection Control Committee or the Greek National Public Health Organization. More female HCWs responded that it should be 14 days, or that they should contact the Hospital Infection Control Committee or the Greek National Public Health Organization compared to men.

When asked regarding their actions after close contact with an asymptomatic COVID-19 patient (both wearing surgical masks), 115 (40.5%) responded they would consult the Hospital Infection Control Committee or the Greek National Public Health Organization, 113 (39.8%) would stay at work with appropriate personal protection equipment and 14 days maintenance of high level awareness for the development of any COVID-19 symptoms and 43 (15.1%) responded they should be isolated for 14 days along with maintaining high level 14 days awareness for the development of any COVID-19 symptoms. When asked about their intention to be vaccinated against SARS-CoV-2, 208 (71.2%) responded positively, 65 (22.3%) responded that they had not decided so far, and 19 (6.5%) responded negatively. Regarding the perceptions of the HCWs on flu vaccination, 135 (47.5%) replied it only protects from flu, 31 (10.8%) replied it also protects against COVID-19, 88 (31%) replied it should be compulsory for all HCWs, and22 (7.7%) replied it should be compulsory for the whole population (Figure 4).

**Figure 3.** Healthcare workers' opinions on aeration and hand-hygiene practices.

**Figure 4.** Healthcare workers' opinions regarding isolation and vaccination.

Among physicians, 98/114 (86%) stated their specialty, and the most common specialties were internal medicine, surgery, pulmonary medicine, and hematology in 18 (18.4%), 15 (15.3%), 11 (11.2%) and 9 (9.2%), respectively (Table S1). Overall, 50 (51.5%) physicians were attendings or consultants, and 47 (48.5%) were residents. Clinical experience was less than 5 years in 45 (44.6%), 5–10 years, and >10 years in 28 (27.7%) each. When asked about the most appropriate testing for COVID-19 diagnosis, 91 (92.9%) considered rhinopharyngeal RT-PCR as the most sensitive test, while 6 (6.1%) replied oropharyngeal RT-PCR is the most sensitive. Female HCWs were more likely to respond that oropharyngeal RT-PCR was the most sensitive. When asked about whether antimicrobials are a first line treatment for COVID-19 patients, 85 (86.7%) replied negatively and 11 (11.2%) positively. Among physicians that replied to the question whether there are specific criteria for antimicrobial prescription in COVID-19 patients, 79 (80.6%) replied positively, 9 (9.2%) negatively, and 10 (10.2%) replied they did not know. When asked regarding the most appropriate indication for starting antimicrobial treatment in COVID-19 patients, 57 (59.4%) replied all of the following are useful: procalcitonin measurement, PCR for respiratory pathogens, sputum and blood cultures, chest X-ray, and computerized tomography. Among physicians, 35 (36.1%) replied they did know what percentage of COVID-19 patients presents with co-infection by other pathogens, while 33 (34%) and 26 (28.8%), respectively, answered the percentage is 1–10% and 30–50%, respectively.

Regarding the termination of isolation for mildly symptomatic COVID-19 patients, 53 (53.5%) replied isolation should be terminated after 14 days after symptoms' initiation (along with 3 days of defervescence), while 25 (25.3%) replied isolation should be terminated 10 days post symptoms' initiation (along with 3 days of defervescence). When asked on the isolation period for asymptomatic patients, 60 (61.2%) replied isolation should be terminated after 14 days after the first positive test, while 30 (30.6%) said that isolation should be terminated after 10 days after the first positive test (Figure 5).

**Figure 5.** Medical doctors' opinions and knowledge regarding antimicrobial use and isolation.

A sub-analysis of the responses was performed in order to compare the knowledge, perceptions and attitudes among physicians and non-physicians, and revealed several differences in the responses of most of the provided questions. Physicians were more likely to be informed from specialized websites and medical journals, were more likely to believe that the virus evolved from a natural mutation of another virus in China, they were more likely to respond correctly to the questions on disinfection, they were less afraid being infected by the virus in their workspace, they were less satisfied from the protective equipment of their hospital, they were more likely to wash their hands after contact with a surface or equipment in their workplace, they were more likely to know the five steps of hand hygiene, while, on the other hand, they were more knowledgeable regarding COVID-19 symptoms and isolation guidelines. Finally, physicians had a higher intention to be vaccinated when a vaccine was available. Another sub-analysis of the data in regards to the hospital revealed that HCWs from the University Hospital of Heraklion and the General Hospital Papageorgiou of Thessaloniki were slightly less afraid of being infected, or of contracting the virus, compared to their relatives.
