A healthcare worker who contracted Omicron after two bouts of Covid and a round of vaccination may be India’s first case of reinfection despite natural- and vaccine-induced protection, investigators from the ICMR-National Institute of Virology (NIV) have said.
The individual first got Covid in October 2020, then experienced a breakthrough infection with Delta (after two doses of Covishield) and was again hit by Omicron during the third wave this year. The time between recovery from Delta and the Omicron reinfection was just about two months, ICMR scientists told, adding that the case demonstrates Omicron’s significant immune-escape abilities.
“An extensive search of the scientific database so far has not revealed any reports of a primary infection, followed by a breakthrough infection and reinfection in India. So the healthcare worker is, presumably, the first such case from the country,” an ICMR scientist said.
The scientist added that genome sequence analysis demonstrated that the case had a breakthrough infection with Delta derivative AY.112 and reinfection with the Omicron sublineage BA.2. “The clinical specimens of the first bout of infection couldn’t be characterized but the probability of B.1 (Wuhan strain) as the infecting variant is higher as the infection occurred in October 2020,” the expert said.
