Protection afforded by the BNT162b2 and mRNA 1273 COVID 19 vaccines in fully vaccinated cohorts with and without prior infection
Effect of prior SARS CoV 2 infection on vaccine protection remains poorly understood. Here, we investigated whether persons vaccinated after a prior infection have better protection against future infection than those vaccinated without prior infection. Effect of prior infection was assessed in Qatar population, where the Alpha (B.1.1.7) and Beta (B.1.351) variants dominate incidence, using two national retrospective, matched cohort studies, one for the BNT162b2 (Pfizer BioNTech) vaccine, and one for the mRNA 1273 (Moderna) vaccine. Incidence rates of infection among BNT162b2 vaccinated persons, with and without prior infection, were estimated, respectively, at 1.66 (95% CI: 1.26 2.18) and 11.02 (95% CI: 9.90 12.26) per 10,000 person weeks. The incidence rate ratio was 0.15 (95% CI: 0.11 0.20) Analogous incidence rates among mRNA 1273 vaccinated persons were estimated at 1.55 (95% CI: 0.86 2.80) and 1.83 (95% CI: 1.07 3.16) per 10,000 person weeks. The incidence rate ratio was 0.85 (95% CI: 0.34 2.05) Prior infection enhanced protection of those BNT162b2 vaccinated, but not those mRNA 1273 vaccinated. These findings may have implications for dosing, interval between doses, and potential need for booster vaccination.
medRxiv