Differential effects of the second SARS-CoV-2 mRNA vaccine dose on T cell immunity in naive and COVID-19 recovered individuals
Daniel Lozano‐Ojalvo, Carmen Cámara, Eduardo López‐Granados, Pilar Nozal, Lucía del Pino Molina, Luz Yadira Bravo‐Gallego, Estela Paz‐Artal, Marjorie Pion, Rafael Correa‐Rocha, Alberto Ortíz, Marcos López‐Hoyos, Marta Erro Iribarren, José Pórtoles, Maria Pilar Rojo-Portoles, Gloria Ojeda, Isabel Cervera, María González-Pérez, Irene Bodega‐Mayor, María Montes‐Casado, Pilàr Portolés, Mayte Pérez‐Olmeda, Jesús Oteo, Rodrigo Sánchez-Tarjuelo, Venu Pothula, Megan Schwarz, Manisha Brahmachary, Anthony T. Tan, Nina Le Bert, M. Cecilia Berin, Antonio Bertoletti, Ernesto Guccione, Jordi Ochando
Abstract
The rapid development of mRNA-based vaccines against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the design of accelerated vaccination schedules that have been extremely effective in naive individuals. While a two-dose immunization regimen with the BNT162b2 vaccine has been demonstrated to provide a 95% efficacy in naive individuals, the effects of the second vaccine dose in individuals who have previously recovered from natural SARS-CoV-2 infection has not been investigated in detail. In this study, we characterize SARS-CoV-2 spike-specific humoral and cellular immunity in naive and previously infected individuals during and after two doses of BNT162b2 vaccination. Our results demonstrate that, while the second dose increases both the humoral and cellular immunity in naive individuals, COVID-19 recovered individuals reach their peak of immunity after the first dose. These results suggests that a second dose, according to the current standard regimen of vaccination, may be not necessary in individuals previously infected with SARS-CoV-2.