Covid-19, the illness caused by the SARS-CoV-2 virus, will likely become seasonal in countries with temperate climates, but only when herd immunity is attained, suggests a new review published in Frontiers in Public Health. Until that time, Covid-19 will continue to circulate across the seasons. These conclusions highlight the absolute importance of public health measures needed just now to control the virus.
"Covid-19 is here to stay and it will continue to cause outbreaks year-round until herd immunity is achieved. Therefore, the public will need to learn to live with it and continue practicing the best prevention measures, including wearing of masks, physical distancing, hand hygiene and avoidance of gatherings," said senior author of the study Dr. Hassan Zaraket, of the American University of Beirut in Lebanon. Collaborating author Dr. Hadi Yassine, of Qatar University in Doha, affirms and states that there could be multiple waves of Covid-19 before herd immunity is achieved. The researchers explain that virus survival in the air and on surfaces, people's susceptibility to infections, and human behaviors, such as indoor crowding, differ across the seasons due to changes in temperature and humidity. These factors influence transmission of respiratory viruses at different times of the year. However, in comparison to other respiratory viruses such as the flu, Covid-19 has a higher rate of transmission (R0), at least partly due to circulation in a largely immunologically naive population. Such seasonality has been reported for other coronaviruses, including those that emerged more recently such as NL63 and HKU1, which follow the same circulation pattern like influenza.
