Covaxin effective against Delta plus variant reveals ICMR study; efficacy not yet known

In a boost to India's COVID inoculation, an ICMR study on Monday, has found that Bharat Biotech's Covaxin was effective against the highly prevalent Delta plus variant. The study has concluded that Covaxin's high titers to Delta plus variant was sufficient to neutralise all COVID-19 variants - Alpha, Delta, Delta AY.1 and B.1.617.3 variants effectively. The study titled 'Comparable neutralization of SARS-CoV-2 Delta AY.1 and Delta in individuals sera vaccinated with BBV152' has been uploaded to pre-print server bioRxiv and is yet to be peer-reviewed.

ICMR: Covaxin can neutralise Delta plus variant

ICMR conducted tests on three categories of subjects namely - 42 individuals (24 females and 18 males) who had received two Covaxin doses, 14 people (8 females, 6 males) who have recovered from COVID and received both COVAXIN doses and breakthrough cases after two-dose vaccination. ICMR observed that those inoculated with two doses showed a 1.5 time reduction in titers against Delta plus, a 3.5-time reduction in those who have recovered from COVID-19 and then received two doses and a 2.8-fold reduction in breakthrough cases. A previous study had shown a 4-fold and an 11-fold reduction in titers against Delta variant in those inoculated with Covishield and Pfizer vaccines respectively. 

ICMR also stated that it is uncertain whether Delta plus variant is capable of causing higher transmissibility, severe disease and evasion of immune response compared to the Delta variant. Till now, the prevalence of Delta plus variant is found to be low in India and the rest of the world. No information is available on the efficacy of currently available vaccines against the Delta plus variant, stated ICMR.

On 2 July, Bharat Biotech finally published Covaxin's phase-3 trial putting an end to all speculations, clocking an overal efficacy of 77.8%. Covaxin is 93.4% efficacious against severe symptomatic cases, 78% effective against mild and moderate cases and 63% effective on asymptomatic cases. The vaccine has also shown 65.2% efficacy against the Delta variant of COVID-19 with the vaccine being well tolerated with no clinically or statistically significant differences in serious adverse events. Covaxin has been tested on 25,800 volunteers across 25 trial sites on subjects ages 18-98 years - India's largest efficacy trial. Covaxin is awaiting WHO's approval which is likely to be decided in September-October.