E-Paper
Kerala case raises fears over incubation period
Kerala has a 28-day mandatory isolation period for those with close contact with a confirmed patient or with a history of travel to hot spot countries.
A man who returned from Dubai on March 18 tested positive for Covid-19 on Thursday, 29 days after what health officials say was his likely exposure to an infection source, raising concerns that the disease could take longer to manifest and quarantine periods as short as 14 days may not be enough.
The brother of this person – both are currently in Kozhikode – tested positive on March 28, prompting authorities to put him under special observation.
“Chances of him being infected during observation period are nil. Since his brother was positive, he was under special observation. We have noticed a couple of such instances from other districts also. It could be that the onset was delayed because of his immunity. We can’t say virus works in a uniform pattern in all bodies,” said Kozhikode district medical officer Dr V Jayashree.
Kerala has a 28-day mandatory isolation period for those with close contact with a confirmed patient or with a history of travel to hot spot countries. This period is double the 14-day isolation that people in other states are mandated to follow.
Self-isolation is advised to keep someone who may have been infected from infecting others. This is particularly complicated in the case of Covid-19, which has an average incubation period (the time it takes for the disease to manifest itself) of around 5 days but has been established to last longer (up to 14 days). An incubation period of 29 days, as was in the case of the Kozhikode man, is rare.
The virus also spreads when people are asymptomatic, making containment tougher.
“True, Kozhikkode man’s case is a peculiar one. We have asked medical experts and scientists to study his case separately. Experts say since it is a new virus its behaviour is unknown and quite erratic,” said state health minister K K Shailaja, adding there was no need to worry.
A student in Pathanamthitta, who shared a train compartment with some Tabligi Jamaat members who later were confirmed as patients, tested positive 22 days after her trip. She was asymptomatic throughout but tested positive when her observation period was about to end and remained asymptomatic even after the test result, said district medical officer Dr N Sheeja.
A scientist at the Indian Council of Medical Research (ICMR) said such a behaviour by the disease cannot be ruled out. “It is possible as there are studies to suggest that. We are also conducting studies to check the incubation period,” said a microbiologist at one of the viral research and diagnostic labs of ICMR, requesting anonymity.
