Delta variant may infect those who received Covishield or Covaxin doses: AIIMS study

As India's COVID-19 cases recede, two separate studies by the All India Institute of Medical Science (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 of COVID-19 is infecting people who have received one or two jabs of either Covishield or Covaxin. 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. Neither study is peer-reviewed as of yet.

What do the studies say?

The AIIMS-IGIB study observed that the B.1.617.2 (Delta) variant was prevalent in the group and that 'no difference was found in both double dose vaccinated group and single-dose vaccinated group'. Moreover, the study stated that while no deaths were reported in the 63 subjects but almost all cases reported high-grade unremitting fever for 5-7 days. Furthermore, the Delta variant was about 60% in people who had two jabs of either vaccine and 77% in those who received one jab. Of the 63 subjects, 10 had received Covaxin and 53 had received Covishield doses. 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". 

Meanwhile, as per reports, the NCDC study showed 'delta' breakthrough infections in 27 patients who had received Covishield with a 70.3% 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. This comes days after an NCDC concluded that the 'delta' variant was behind the second Covid-19 wave in India.

Covaxin neutralises Beta & Delta variant: ICMR study

On Monday, an ICMR study established that Bharat Biotech's Covaxin is effective in neutralising both COVID variants -B.1.351 (Beta) and B.1.617.2 (Delta). The study, yet to be peer-reviewed, was performed 5-20 weeks after infection on 20 individuals who had recovered COVID-19 and on 17 subjects who have who received both doses of Covaxin, 28 days after the jabs. The study observed the neutralisation potential of Covaxin on the two variants Beta and Delta compared to the regular COVID-19 virus B.1 (D614G). The study demonstrated that while Covaxin's neutralisation capacity is reduced against the two variants, the potential is well established.