The incubation period went from 5 days with alpha infection to 3.42 with omicron, the study showed (File)
The longer a virus can replicate inside a person before causing symptoms, the harder it is to stop because of the greater potential that those infected are unknowingly spreading it.
Among the pernicious features of Covid-19, its incubation period is longer than many other respiratory viral infections, such as influenza, respiratory syncytial virus and rhinovirus. The good news is that the interval between exposure and the development of symptoms appears to be shortening.
Scientists from Peking University and Tsinghua University in Beijing analyzed data from more than 140 studies to estimate the incubation period of Covid caused by different strains of SARS-CoV-2. It dropped from an average of five days with an alpha infection to 3.42 days with omicron, according to a study published Monday in the journal JAMA Network Open.
The researchers also observed variable incubation periods in different age groups and disease severity.
“The results of this study suggest that SARS-CoV-2 has continuously evolved and mutated throughout the Covid-19 pandemic, producing variants with different enhanced transmission and virulence,” said Wannian Liang and colleagues. . “Identifying the incubation period of different variants is a key factor in determining the period of isolation.”
The findings are significant for places like China and Hong Kong, which maintain a Zero Covid policy aimed at eliminating any sign of the virus as soon as possible. All infected persons and all foreign travelers are expected to self-isolate during the potential incubation period to prevent transmission to others.
Both China and Hong Kong have recently reduced quarantine periods for new arrivals as part of their efforts to revive their economies.
(Except for the headline, this story has not been edited by NDTV staff and is being published from a syndicated feed.)