Does Single Dose of COVID Vaccine Provide Protection against Variants?


A recent study suggests that single dose of Pfizer/BioNTech mRNA vaccine BNT162b2 provide protection against the new variants among individuals with prior infection.  

The massive immunisation programme against the pandemic COVID-19 is currently underway. Simultaneously, there are reports of emergence of new variants of concern of SARS-CoV-2 virus. With the countries like UK having successfully given first dose to significant section of population, the question is often raised about effectiveness of single dose of COVID vaccine in providing adequate protection against the new variants of SARS-CoV-2 virus.  

A recent study has looked in this aspect for Pfizer’s mRNA vaccine. The researchers investigated if single dose vaccination provides cross protective immunity to variants.  


Upon analysis of T and B cell responses after first dose vaccination with the Pfizer/BioNTech mRNA vaccine BNT162b2 in healthcare workers, the researchers found that those with prior infections had enhanced T cell immunity, antibody secreting memory B cell response to spike and neutralizing antibodies effective against B.1.1.7 and B.1.351. On the other hand, in individuals without prior infection, the single dose of the vaccine showed reduced immune response against variants. B.1.1.7 and B.1.351 spike mutations.  



Reynolds C., Pade C., et al 2021. Prior SARS-CoV-2 infection rescues B and T cell responses to variants after first vaccine dose. Science. Published 30 Apr 2021: eabh1282. DOI: