Prior #SARS-CoV-2 infection primes the immune response to one dose of Pfizer/BioNTech vaccine | UK-CIC
One dose of the Pfizer/BioNTech vaccine generated antibody and T cell responses in all but one of the 103 SARS-CoV-2 naïve participants. These responses were at a similar level or higher to those observed in individuals who had previously been infected with SARS-CoV-2 but were yet to be vaccinated.
After one dose of the vaccine, participants who had prior SARS-CoV-2 infection showed significantly higher antibody and T cell responses compared with SARS-CoV-2 naïve individuals, with antibody responses approximately 6.8 times higher and T cell responses approximately 5.9 times higher. [...] The previously infected group appear to receive an extra ‘boost’ to their immune defences from vaccination, which could further decrease their risk of infection if they were to come across the virus.
[...] This is important as this broader response induced by vaccination could provide more robust protection against different viral variants should they be encountered. The study also found that the high antibody responses in previously infected individuals after vaccination may also retain activity against some SARS-CoV-2 variants of concern.
In the ‘naïve’ cohort who received two vaccine doses, their T cell responses were equivalent to those observed in participants who had previously had COVID-19 after one dose. However, antibody levels were still significantly lower than those observed in participants who previously had #COVID-19 after one vaccine dose.