**4. Discussion**

In the present study more health care workers exhibiting URTI/LRTI-like symptoms tested positive for common respiratory viruses, particularly rhinoviruses [13], than pandemic-related COVID-19. Our results are comparable to the outcome of an earlier study from China which tested clinically suspected COVID-19 patients for SARS-CoV-2 and other respiratory viruses. Their findings showed that 1% were positive for SARS-CoV-2, with an overall detection rate of other respiratory pathogens of 10%, and rhinovirus also being the most common underlying virus (3%). However, the coinfection rate was higher at 12% [14]. Notably, coinfections in our samples were observed more commonly with bocavirus (four samples that had coinfections with other respiratory viruses). Two (<1%) confirmed SARS-CoV-2 positive samples also had coinfections. Reported rates of coinfection of SARS-CoV-2 and other respiratory viruses range from 1% to 20% [15–17].

Among those who had coinfections, only one HCW yielded positive results for three etiologic agents (SARS-CoV-2, Influenza A and Parainfluenza (1); a 48-year-old, male who was tested on the fifth day of illness. He was categorized as low-risk exposure and presented with fever, sore throat, cough, fatigue and loss of appetite.

The signs and symptoms exhibited by those who tested positive for respiratory viruses other than COVID-19 were indistinguishable from those observed among persons who tested positive for SARS-CoV-2 [5]. Based upon symptoms alone it is a challenge to identify patients with acute respiratory illness (ARI) and COVID-19, primarily because their presenting signs and symptoms are almost similar at the outset. In the context of HCWs who are attending to COVID-19 patients in a developing country like the Philippines, where hospitals are usually understaffed, it is crucial to clarify the actual infection rate of SARS-CoV-2 and other respiratory viruses. At the moment, for HCWs presenting with mild symptoms who tested negative for SARS-CoV-2, for example, this guides decisions regarding continuing quarantine versus allowing to work. In addition to relieving the burden of "shift fatigue" among HCWs, a definitive diagnosis of "something other than COVID-19" should also help alleviate unnecessary anxiety. A limitation of this study is that we tested for an incomplete panel of viruses, and no bacterial pathogens. Subclinical viral infection is common, particularly rhinovirus, among healthy individuals [18], and it is possible that the symptoms of the HCWs in our study could be explained by other causative agents than those in the respiratory viral panel we tested. Further studies could test for an expanded range of pathogens relevant to respiratory illness.
