Two doses of Sputnik V can cause 92% efficacy against coronavirus disease 2019, which is caused by SARS-CoV-2, as per previous research.

The AstraZeneca vaccine shows 76% efficacy after a single dose, and the Moderna and Pfizer vaccines may induce sufficient immunity in previously infected individuals after one dose, with no apparent benefit of an additional dose.

In the current study, Gamarnik and her colleagues compared the effects of one and two shots of Sputnik V on SARS-CoV-2-specific antibody responses in 289 healthcare workers in Argentina. All volunteers have no prior infection generated virus-specific immunoglobulin G (IgG) antibodies.

Within three weeks of receiving the first dose, 94% of participants developed IgG antibodies, and 90% showed evidence of neutralizing antibodies, which interfere with the ability of viruses to infect cells.

IgG and neutralizing antibody levels in previously infected subjects were higher after one dose than those in fully vaccinated volunteers with no history of infection. A second dose did not increase the production of neutralizing antibodies in previously infected volunteers.

“This highlights the robust response to vaccination of previously infected individuals, suggesting that naturally acquired immunity might be enhanced sufficiently by a single dose, in agreement with recent studies using mRNA vaccines,” Gamarnik says.

More studies are required to know the duration of the immune response and to assess how antibody levels relate to vaccine protection against COVID-19.

“Evidence based on quantitative information will guide vaccine deployment strategies in the face of worldwide vaccine supply restriction,” Gamarnik says.

Source: Medindia