Even as the COVID-19 cases are showing a steady decline over the past few days, All India Institute of Medical Science (AIIMS) studies have some worrisome observations. Two separate studies by AIIMS, in collaboration with the Institute of Genomics and Integrative Biology (IGIB) and the National Centre for Disease Control (NCDC), have shown that the Delta variant (B.1.617.2) of COVID-19 is infecting people who have received one or both jabs of either Covishield or Covaxin vaccines.
The AIIMS study was conducted on 63 subjects who had breakthrough infections – 36 of whom had received two doses, while 27 had gotten one dose.
The AIIMS-IGIB study observed that the Delta variant was prevalent in the group and that ‘no difference was found in both double dose vaccinated group and single-dose vaccinated group’. While no deaths were reported in the 63 subjects but almost all cases reported high-grade unremitting fever for at least 5-7 days.
About 60 per cent of people who had two jabs of either Covishield or Covaxin and 77 per cent of those who received one jab showed signs of the Delta variant. Of the 63 subjects, 10 had received Covaxin and 53 had received Covishield doses and 51 were males, 22 were females.
The study concluded, “Reinfections and vaccine breakthrough infections are rare occurrences and genome sequencing can provide useful insights. In the present group of vaccine breakthrough infections investigated closely overlapping the COVID cases in Delhi, the Delta variants compromised the majority, but the proportions were not significantly different compared to the population prevalence of the variants during this period with high community transmission”.
The NCDC study showed Delta infections in 27 patients who had received Covishield with a 70.3 per cent infection rate.
Both studies have stated that both vaccines are effective against the variants but with reduced effectiveness. It also stated that the severity of infection in each case appeared to be unaffected as a result.