Don’t Miss Out on the Latest Updates.
Subscribe to Our Newsletter Today!
A new study published in the journal Science suggests the SARS-CoV-2, the virus that causes COVID-19 may resemble the mild cold-causing coronaviruses that currently circulate in humans if it becomes endemic and most people are exposed in childhood.
The researchers noted that four common cold-causing coronaviruses have been circulating in humans for a long time and almost everyone is infected at a young age.
According to the author of the study, natural infection in childhood provides immunity that protects people later in life against severe disease, but it doesn't prevent periodic reinfection.
The research suggests that endemic SARS-CoV-2 may become a disease of early childhood, where the first infection occurs between 3 and 5 years old, and the disease itself would be mild.
The study stressed that older individuals could still become infected, but their childhood infections would provide immune protection against severe disease.
How fast this shift comes depends on how fast the virus spreads and what kind of immune response the SARS-CoV-2 vaccines induce.
The researchers suggest that if the vaccines induce short-lived protection against becoming reinfected but reduce the severity of the disease, as is the case with other endemic coronaviruses, SARS-CoV-2 may become endemic more quickly.
"This model assumes immunity to SARS-CoV-2 works similar to other human coronaviruses. We don't really know what it would be like if someone got one of the other coronaviruses for the first time as an adult, rather than as a child," one of the researchers was quoted as saying.
The model predicts that the infection fatality ratio for SARS-CoV-2 may fall below that of seasonal influenza (0.1 per cent), once an endemic steady-state is reached.
"We are in uncharted territory, but a key take-home message from the study is that immunological indicators suggest that fatality rates and the critical need for broad-scale vaccination may wane in the near term," said Ottar Bjornstad, a professor, and epidemiologist at Penn State.
He noted that maximum effort should be on weathering this virgin pandemic enroute to endemicity.
A safe and effective vaccine against COVID-19 could save hundreds of thousands of lives in the first year or two of vaccine roll-out, but continued mass vaccination may be less critical once SARS-CoV-2 becomes endemic, the researchers said.
Targeted vaccination in vulnerable subpopulations may still save lives, they said.
The researchers also noted that if primary infections of children are mild when the virus becomes endemic, widespread vaccination may not be necessary.
However, if primary infections become severe in children, as in the case of more deadly but contained coronaviruses such as MERS, childhood vaccinations should be continued, the added.
The World Health Organization's chief scientist warned that even as numerous countries start rolling out vaccination programs to stop COVID-19, herd immunity is highly unlikely this year.
At a media briefing on Monday, Dr. Soumya Swaminathan said it was critical countries and their populations maintain strict social distancing and other outbreak control measures for the foreseeable future.