In the biggest research of breakthrough infections of COVID-19 among healthcare workers in India so far, it was found that 16 in every 1,000 fully-vaccinated healthcare professionals developed the infection. This is three times more than such incidences observed in a US study after Pfizer or Moderna doses.
The study that has been carried out by the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh and published in the The New England journal of Medicine, found that the rate of breakthrough infections was 1.6 percent among those fully vaccinated.
Breakthrough infections are cases in which a person gets COVID-19 infections, 14 days after receiving the second dose of the vaccine.
The study was conducted on 12,248 healthcare workers, 7,170 of whom had received the first dose of the vaccine and 3,650 had got the second dose.
A total of 5078 health care workers were unvaccinated while the rest had all received Covishield.
The study found that 184 of 7170 health care workers (2.6 percent) tested positive after receiving at least one dose of vaccine and the median time between receipt of the first dose and the positive test was 44 days.
On the other hand, a total of 72 of 3650 health care workers (2.0 percent) tested positive after the second dose and the median time from receipt of the second dose to the positive test was 20 days, the study found.
“Among the healthcare workers who received both doses and completed at least 14 days of follow-up after the second dose, the incidence of breakthrough infection was 1.6 percent (48 of 3000 health care workers),” the researchers said.
The earlier study of breakthrough infections in India had smaller samples. Last month, a study at a private hospital in Delhi found that breakthrough infections occurred in 13.3 percent or about 1 in 7 healthcare workers, with one requiring hospitalisation. The hospital had 123 employees out of whom 113 had been vaccinated by the time the study took place.
Meanwhile, the Union Health Ministry has said the incidence of such cases in both vaccines in use in India — Covaxin and Covishield — has remained low.
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