Analysis of Covid-19 and non-Covid-19 viruses, including influenza viruses, to determine the influence of intensive preventive measures in Japan.

BACKGROUND

Severe acute respiratory coronavirus 2 (SARS-CoV-2) has spread and caused death worldwide. Preventive measures and infection control are underway, and some areas show signs of convergence. Other viruses in addition to SARS-CoV-2 cause cold-like symptoms and spread in the winter. However, the extent to which SARS-CoV-2, influenza viruses and other causative viruses have prevailed since implementing preventive measures is unclear.

OBJECTIVES

We aim to investigate the incidence of causative viruses and pathogens in patients.

STUDY DESIGN

We collected 191 nasopharyngeal swabs from patients with cold-like symptoms in Japan. All samples were subjected to multiplex PCR with the FilmArray Respiratory Panel and reverse transcription PCR (RT-PCR) to detect SARS-CoV-2.

RESULTS

FilmArray Respiratory Panel analysis detected at least one virus in 32 of 191 patients with cold-like symptoms (21 %). Of these, we frequently identified human rhinoviruses/enteroviruses (5.8 %, n=11), human metapneumovirus (3.7 %, n=7), coronavirus 229E (2.1 %, n=4) and coronavirus OC43 (1.6 %, n=3); while no influenza viruses were detected. RT-PCR analysis detected SARS-CoV-2 (4.2 %, n=8) in patients who were not infected with the aforementioned respiratory viruses.

CONCLUSIONS

Co-infection with SARS-CoV-2 and other viruses was not observed. Causative viruses remain prevalent after implementing preventive measures. SARS-CoV-2 differs from influenza viruses in its infectivity.