Human metapneumovirus-associated community-acquired pneumonia in adults during the first wave of COVID-19

Detection of Respiratory Viruses in SARS-CoV-2-Negative Specimens from January to March 2020 in Fukuoka, Japan

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first cases confirmed in Japan on January 15, 2020. The Fukuoka Institute of Health and Environmental Sciences conducted testing by polymerase chain reaction (PCR) for SARS-CoV-2 from January 31 to March 4, 2020. Despite collecting 119 samples from 81 patients with fever, cough, fatigue, pneumonia, and other symptoms who were suspected as having SARS-CoV-2 infection, all samples tested during that period were negative. To investigate the pathogens responsible for these symptoms, we conducted multiplex polymerase chain reaction. The results showed that respiratory viruses, human metapneumovirus (hMPV) was detected in 10 patients (12%), human rhinovirus (HRV) in 3 patients (4%), and influenza B virus in 1 patient (1%). In addition, the patients found as having the viruses were significantly older than those not found as having the viruses. Infection with hMPV and HRV has been reported to be associated with the risk of severe illness and death among the elderly. Therefore, differentiating SARS-CoV-2 as well as other respiratory viruses such as hMPV and HRV is necessary to prevent and control the spread of infection, especially in the elderly.