Indraprastha Apollo Hospital, New Delhi released the results of an observational study of healthcare workers to evaluate the frequency of break through infection (BTI) of COVID-19.

BTI refers to people who are fully vaccinated who still get infected with COVID-19. The observational study was carried out on healthcare workers who reported to Indraprastha Apollo Hospital, New Delhi with symptomatic COVID-19, during the first 100 days of the vaccination drive using the Covishield vaccine. The findings of the study are under consideration for publication in a peer-reviewed medical journal.

Dr Anupam Sibal, Group Medical Director, Apollo Hospitals Group and Sr Consultant, Paediatric Gastroentereology said, “Our study demonstrates that 97.38 per cent of those vaccinated were protected from infection and hospitalisation rate was only 0.06 per cent. The results of the study show that BTI occurs only in a small percentage and these are primarily minor infections that do not lead to severe disease. There were no ICU admissions or death. Our study makes the case for vaccination stronger.”

The study covered 3235 healthcare workers (HCWs). A total of 85 of the 3235 HCWs acquired the SARS-COV-2 infection during the study period. Out of these, 65 (2.62 per cent) were fully vaccinated, and 20 (2.65 per cent) were partially vaccinated. Females were significantly more affected and the age did not influence the incidence of infection.

Dr Raju Vaishya, Sr Consultant Orthopaedics, Indraprastha Apollo Hospital, New Delhi and one of the key authors of the study added, “COVID vaccines take time to develop adequate immunity in the human body with current studies indicating immunity takes two weeks to properly develop after the second vaccine dose. Hence, if due precautions and preventive measures are not taken by the vaccinated person during this time, the BTI may occur. Even after vaccination, it is essential to continue to take precautions to avoid any chance of exposure to the novel coronavirus.”

The study emphasises the fact that COVID-19 vaccines are effective with vaccine breakthrough occurring only in a small percentage of vaccinated persons.