A new study by Chinese researchers, published in the journal Science Advances , showed that the incubation period of the Covid-19 virus is now estimated at 7.76 days, against the earlier 4-5 days.

The incubation period is the period between exposure to an infection and the appearance of the first symptoms.

The researchers conducted a cross-sectional and forward follow-up study by identifying those pre-symptomatic individuals at the time of their departure from Wuhan and then following them until their symptoms developed.

Researchers added that the effectiveness of the Covid-19 strategies such as 14-day isolation, social distancing, etc. depend largely on the understanding of the incubation period of the virus.

The scientists believe that researchers lack a reliable estimate of the incubation period of Covid-19. The few existing estimates of 4-5 days were based on small sample sizes, limited data, and self-reports that could be biased by the memory or judgment of the patient or interviewer.

For the current findings, the team of researchers came up with a low-cost approach to estimate incubation periods and applied it to 1,084 confirmed cases of Coivd-19 that had known histories of travel or residency in Wuhan.

The team calculated that the median incubation period was 7.75 days, with 10 per cent of patients showing an incubation period of 14.28 days. The authors noted that their findings may concern health authorities relying on the standard 14-day quarantine.

They further cautioned that their approach relies on several assumptions and may not apply to later cases where the virus may have mutated.