The study found that both Covishield and Covaxin, which were the only vaccines available in India when the research was conducted (April 24 to May 31, 2021), are effective in preventing disease severity and mortality against the Delta variant (B.1.617.2) in completely vaccinated hospitalised patients. The study, which appeared in the preprint online platform, MedRxiv, on July 13 was updated on July 16.
While 3.45% of hospitalised unvaccinated patients died fighting the Delta variant, only 1.51% of fully vaccinated hospitalised patients succumbed to the new variant that fuelled the second wave of Covid-19 in India. Those who received single dose of vaccine had a mortality rate of 3.35%.
“Severity of the disease (severity/ICU requirement at admission) was significantly low in the vaccinated group when compared to the unvaccinated (3.18% versus 7.06%). Requirement of ventilatory support was low as well (2.8% versus 5.7%). No significant differences were seen in the incidence of acute kidney injury, requirement for renal replacement therapy or thrombotic complications between both the groups,” the research study said.
Referring to mortality, the researchers said mortality was 50% lower in fully vaccinated individuals (completed 14 days after receiving second dose) hospitalised with Covid-19 when compared to unvaccinated individuals.
“These results become even more significant in the light of higher comorbidities and age in the vaccinated group. Majority of deceased in completely and partially vaccinated individuals had no/minimal antibody response which was comparable to unvaccinated individuals. Strategies targeting these non-responders to vaccination like additional booster doses or change of vaccine type need to be explored further,” they suggested.
The study found that both Covishield and Covaxin, which were the only vaccines available in India when the research was conducted (April 24 to May 31, 2021), are effective in preventing disease severity and mortality against the Delta variant