COVID-19: Why Are States Opting For 28-Day Quarantine Period?

Bhubaneswar: The Odisha government on Friday extended the quarantine period for returnees from 14 days to 28. This includes 21 days in the quarantine centre and home quarantine for 7 days.

Kerala was the first state to announce a 28-day quarantine period, early in April, followed by Karnataka, Assam and now Odisha.

What prompted state governments to take this step?

In the case of both Kerala and Karnataka, the step was necessitated due to foregin returnees. Many who returned from abroad were asymptomatic for a long time and tested positive much after their quarantine period ended. Kerala followed a strict 28-day isolation period. High-risk category people were tested, even though they were asymptomatic. All were kept in strict mandatory isolation with regular follow-ups.

Assam decided to extend the quarantine period for all asymptomatic direct contacts of a COVID-19 positive case having links with Tablighi Jamaat to 28 days after a few of them became symptomatic much after the stipulated 14 days.

The Odisha government took the decision after it was observed that the incubation period can extend up to 28 days.

What is the incubation period for COVID-19?

Symptoms may develop two days to two weeks following exposure to the virus. A pooled analysis of 181 confirmed cases of COVID-19 outside Wuhan, China, found the mean incubation period to be 5.1 days and that 97.5% of individuals who developed symptoms did so within 11.5 days of infection. 

Take the case of a Kerala man who returned from Dubai. He was asked to self-isolate at home for 28 days even though he had no symptoms related to the virus. He had come on March 19 and was tested on April 14 while he was still asymptomatic. After two days, he was found to be COVID-19 positive.

The Kannur District Medical Officer told the media that of the 248 people who had returned from abroad and were tested for the virus, 17 were found COVID-19 positive. Around 95 per cent of these 17 cases were asymptomatic.

In many states, patients are tested for COVID-19 only after they show symptoms during the 14-day isolation period.

“There was a case in Wuhan where symptoms appeared on the 27th day. At least five per cent of cases have an incubation period longer than 14 days. That is the logic behind Kerala standing strong on a 28-day isolation period,” Dr Mohammed Asheel, member of a core team involved in COVID-19 containment measures in Kerala, had told a leading news portal.

“In Kerala, it is not like the incubation period is 26 days. Rather, the incubation period is seen as the number of days between exposure and appearance of symptoms and almost 60 percent of COVID-19 cases have only minor symptoms. There are cases here where the incubation is anyway more than 14 days,” he had said.

What studies show?

Studies published in various journals say that around 95 per cent of people develop symptoms between 0 and 14 days (or a median of five days). The remaining five per cent can turn symptomatic even after 24 days and up to a month.

Although this five per cent could translate into a statistically small sum, it highlights the chances of a fresh outbreak, or an intensification of the current, of one of the most contagious viruses in recent times.

The last word

“The most important lesson we need to learn is that even asymptomatic people can spread the virus – beyond 14 days. And this may be beyond just five per cent of cases,” Dr Asheel said.