Former Himachal Pradesh Chief Minister Virbhadra Singh tested positive for Covid-19 on Friday for the second time within two months, ANI reported. The state health secretary said that Singh, who had tested positive for the first time on April 12, has been admitted to the Indira Gandhi Medical College and Hospital in Shimla.
The development is significant as most studies have so far shown that it is unlikely for a Covid-19 patient to get reinfected in less than six months.
A study conducted by the Oxford University in November 2020 among healthcare workers in the United Kingdom showed that individuals who have previously had Covid-19 were highly unlikely to contract the illness again, for at least six months following their first infection.
Another research published in the journal Nature in January showed similar results, adding that the immune system of the patient evolves long after the infection and may block even mutant forms of the virus, like the Beta variant, first detected in South Africa.
A study on Covid-19 reinfection published in medical journal Lancet in March also detected that the antibodies against the virus lasted for more than six months.
However, one study in India published in the journal eLife found that 20-30% of infected people had declining virus neutralising activity despite having stable seropositivity six months later, The Hindu reported in April.