Marit J. van Gils, Hugo D. van Willigen, Elke Wynberg, Alvin X. Han, Karlijn van der Straten, Anouk Verveen, Romy Lebbink, Maartje Dijkstra, Judith A. Burger, Melissa Oomen, Khadija Tejjani, Joey H. Bouhuijs, Brent Appelman, Ayesha H.A. Lavell, Meliawati Poniman, Tom G. Caniels, Ilja Bontjer, Lonneke A. van Vught, Alexander P.J. Vlaar, Jonne J. Sikkens, Marije K. Bomers, Rogier W. Sanders, Neeltje A. Kootstra, Colin Russell, Maria Prins, Godelieve J. de Bree, Menno D. de Jong, RECoVERED Study Group



Background The urgent need for, but limited availability of, SARS-CoV-2 vaccines worldwide has led to widespread consideration of dose sparing strategies, particularly single vaccine dosing of individuals with prior SARS-CoV-2 infection.

Methods We evaluated SARS-CoV-2 specific antibody responses following a single-dose of BNT162b2 (Pfizer-BioNTech) mRNA vaccine in 155 previously SARS-CoV-2-infected individuals participating in a population-based prospective cohort study of COVID-19 patients.

Participants varied widely in age, comorbidities, COVID-19 severity and time since infection, ranging from 1 to 15 months. Serum antibody titers were determined at time of vaccination and one week after vaccination. Responses were compared to those in SARS-CoV-2-naive health care workers after two BNT162b2 mRNA vaccine doses.

Results Within one week of vaccination, IgG antibody levels to virus spike and RBD proteins increased 27 to 29-fold and neutralizing antibody titers increased 12-fold, exceeding titers of fully vaccinated SARS-CoV-2-naive controls (95% credible interval (CrI): 0.56 to 0.67 v. control 95% CrI: −0.16 to −0.02). Pre-vaccination neutralizing antibody titers had the largest positive mean effect size on titers following vaccination (95% CrI (0.16 to 0.45)). COVID-19 severity, the presence of comorbidities and the time interval between infection and vaccination had no discernible impact on vaccine response.

Conclusion A single dose of BNT162b2 mRNA vaccine up to 15 months after SARS-CoV-2 infection provides neutralizing titers exceeding two vaccine doses in previously uninfected individuals. These findings support wide implementation of a single-dose mRNA vaccine strategy after prior SARS-CoV-2 infection.