We have all faced the onslaught of seasonal diseases at some point for the other in our lives. The monsoon season in India particularly comes with a plethora of infections, then be it typhoid or dengue and malaria. Turns out there might be another addition to this list of ailments soon, as scientists reckon covid-19 is likely to become a seasonal disease in countries with temperate climates when herd immunity is attained.
A review published in the journal Frontiers in Public Health suggests that till the time herd immunity is not attained, covid-19 will continue to circulate all-year long.
The senior author of the study, Dr. Hassan Zaraket, of the American University of Beirut in Lebanon says: “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 masks, physical distancing, hand hygiene, and avoidance of gatherings (sic).”
Collaborating author, Dr Hadi Yassine, of Qatar University in Doha, also stated that we could see multiple waves of covid-19 before reaching the stage of herd immunity.
The researchers have more to add on the patterns on seasonal diseases
The authors reviewed these seasonal viruses, examining the viral and host factors that control their seasonality as well as the latest knowledge on the stability and transmission of SARS-CoV-2.
The researchers then explained that the survival of viruses in the air and on surfaces, people’s susceptibility to infections, and human behaviours—such as indoor crowding, differ across seasons due to changes in temperature and humidity. These factors influence the 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. This means that unlike the flu and other respiratory viruses, the factors governing seasonality of viruses cannot yet halt the spread of covid-19 in the summer months.
“The highest global covid-19 infection rate per capita was recorded in the Gulf states, regardless of the hot summer season. Although this is majorly attributed to the rapid virus spread in closed communities, there’s still a need for rigorous control measures to limit virus spread, until herd immunity is achieved,” Dr Yassine said.
But, once herd immunity is attained through natural infections and vaccinations, the rate of transmission should drop substantially, making the virus more susceptible to seasonal factors. Such seasonal infections have been reported for other coronaviruses, including NL63 and HKU1, which follow the same circulation pattern as influenza.
“This remains a novel virus and despite the fast-growing body of science about it, there are still things that are unknown. Whether our predictions hold true or not remains to be seen in the future. But we think it’s highly likely, given what we know so far, covid-19 will eventually become seasonal, like other coronaviruses,” concluded Zaraket.