New Delhi: Bharat Biotech’s COVID-19 vaccine Covaxin has shown less reduction in ‘neutralising activity’ while comparing with Delta and Delta AY.1 (Delta plus) variants in those who are fully vaccinated with the vaccine according to a study by the Indian Council of Medical Research-National Institute of Virology (NIV).
This means that people vaccinated with Covaxin will be protected against the current variants Delta, Delta AY.1 and B.1.617.3.
The MoHFW on June 22 designated the ‘Delta Plus’ variant of the novel coronavirus, as a “variant of concern”. Currently, India has as many as 70 cases of Delta plus variant.
According to the study, “A minor reduction was observed in the neutralising antibody titer in COVID-19 recovered cases full BBV152 vaccinated and post immunised infected cases compared to COVID-19 naive vaccinated individuals.”
The study was conducted with samples collected from three groups.
Group 1 samples were collected after two doses with a gap of 2.5 to 22 weeks, “Group 1, Sera of individuals vaccinated with two doses of COVAXIN [Female (n=24) and Male (n=18)] collected between 2.5 to 22 weeks after second dose.”
After group 1, samples of those individuals were collected who had taken the second dose and recovered from Covid-19, “Group 2: COVID-19 recovered cases with two doses of COVAXIN [female (n=8); male (n=6)], collected 14-70 weeks after the second dose.”
The last samples were collected from group 3, “Group 3: breakthrough cases post two-dose COVAXIN vaccinations [female (n=17); male (n=13)] collected between 2-18 weeks.”
“However, with the observed high titers, the sera of individuals belonging to all the aforementioned groups they would still neutralize the Delta, Delta AY.1 and B.1.617.3 variants effectively,” said the study.
“The vaccine sera effectively neutralises the Delta, Delta AY.1 and B.1.617.3 in spite of some reduction in titer, which means vaccination will protect against these variants,” Dr Pragya Yadav, head of the NIV’s Maximum Containment Facility told ANI.
“Sera of individuals who were fully immunized (with 2 doses) didn’t show significant reduction in the NAb titer against Delta, Delta AY.1 and B.1.617.3”, said Dr Samiran Panda, Head of epidemiology and infectious diseases.
NAb titer of sera of recovered cases with vaccinations and breakthrough cases were significantly high compared to those with two doses of vaccinations.
According to Dr Samiran Panda, Immunization is key to protect from severity and deaths in the current situation and reduce the burden on healthcare system.
“A significant increase in NAb titer was also observed among these two groups against Delta, Delta AY.1 and B.1.617.3 variants. This demonstrates the possible role of memory cells in immune boosting with post-infection or infection after immunization. The comparative analysis of all the groups revealed that the B.1.617.3 variant seems to be less susceptible to neutralization followed by Delta AY.1 and Delta variants compared to B.1 “, stated the study.
A recent study published by Hacisuleyman E, demonstrated a reduction in neutralization by 4 fold and 11 fold against Delta variant with the sera of healthy individuals vaccinated with two doses of ChAdOx1 and BNT162b2 vaccine respectively.