New Delhi | Jagran News Desk: In a worrying development, the Indian Council of Medical Research (ICMR) on Tuesday informed that three cases of COVID-19 re-infection have been reported in the country. While two of them were reported from Mumbai, one person re-infected the deadly virus in Ahmedabad.

ICMR Director General, Balram Bhargava, while highlighting inputs on the COVID-19 re-infection said that the time limit for re-infection was fixed at 100 days as many studies on the coronavirus have revealed that antibodies usually remain present in a person's body for nearly four months.

Bhargava said that re-infection is a problem, which first surfaced in Hong Kong, adding that the ICMR received some data from the World Health Organization (WHO), referring to two dozen cases of re-infection worldwide. Efforts are being made to collect some more data by talking to people who have been re-infected by telephone, he said.

Bhargava further stated that the WHO has also not yet stated whether a person can become infected again after 90 days, 100 days or 110 days. But now the government has fixed its time limit to 100 days. According to this, there is a risk of COVID-19 re-infection after 100 days.

Meanwhile, a study published in The Lancet Infectious Diseases journal, charting the first confirmed case of COVID-19 reinfection in the United States, stated that COVID-19 patients may experience more severe symptoms the second time they are infected with the deadly infection.

The study also indicates that exposure to the virus may not guarantee future immunity. However, experts say it is too early to draw any conclusions from such small samples of re-infection.

"The possibility of reinfections could have significant implications for our understanding of COVID-19 immunity, especially in the absence of an effective vaccine," said Mark Pandori, the lead study author, as quoted by news agency AFP.

"We need more research to understand how long immunity may last for people exposed to SARS-CoV-2 and why some of these second infections, while rare, are presenting as more severe", the author added.

According to the AFP report, vaccines trigger the body's immune system to a certain pathogen, arming it antibodies to fight future re-infections, however, it is not clear how long does the COVID-19 antibodies last in a person's body. For some infections like measles, lifelong immunity is developed in a person's body, while for some pathogens, immunity is shot-lived.

The Lancet study indicates that the person re-infected in the US could have been exposed to a very high dose of the coronavirus the second time around, developing more severe symptoms. Alternatively, it may have been a more virulent strain of the virus.

Another possibility, the study indicates, that the patient might have developed antibody-dependent enhancement -- that is, when antibodies actually make subsequent infections worse, such as with dengue fever.

However, the researchers noted that COVID-19 re-infection remains rare with only a few confirmed re-infected cases out of tens of millions of COVID-19 infections globally.

Posted By: Talib Khan