Over 25 per cent of healthcare workers were found Covid infected despite getting fully vaccinated, a recent study has said. The study was jointly conducted by the Institute of Genomics and Integrative Biology (IGIB) and Max hospitals in Delhi-NCR. It has been found that vaccination breakthroughs were far more common during the Delta surge in Delhi than reported previously.
However, none of the nearly 600 vaccine recipients required hospitalization. This is the first time that such a high percentage has been reported as part of a single study.
However, the severity of the infection was low and vaccination is crucial to avoid severe illnesses, said senior scientist with the IGIB Shantanu Sengupta. He is one of the lead researchers of the study.
Sengupta said nearly 95 healthcare workers who had taken the two doses were studied. They were assessed from 45-90 days after their inoculation. Of the 95, more than 25 per cent saw breakthrough infections.
The timing between the first and second dose varied, but 482 received the second dose within 42 days of the first dose. About half the recipients had been previously infected with SARS-CoV-2.
The study was done in one cohort of 597 health care workers, divided into two groups – seropositive (SP) and seronegative (SN), based on their serology status at baseline. 52% of subjects (n=309) had been previously infected with SARS-CoV-2, based on the presence of antibodies to SARS-CoV2 proteins. There was a robust immunogenic response to two doses of vaccine, irrespective of prior infection.
Amongst fully vaccinated and uninfected HCWs, the breakthrough infection prevalence on day 90 was 25.3%.