Is a single COVID-19 vaccine dose enough in convalescents ?

SARS-CoV-2 has infected more than 122 million persons worldwide. Most currently licensed COVID-19 vaccines require a two-dose course and many health systems are on a shortage of doses. The requirement for boosting the response after priming with the first dose is uncertain in convalescents already primed by the natural infection. Mounting evidences suggest that, after a single vaccine dose, convalescents develop antibody (total and neutralizing) levels similar to the ones measured in naïve vaccinees after the full two-dose course. While concerns remain on the equivalent duration of such response, optimizing vaccine delivery to convalescents seems effective and could accelerate achievement of herd immunity.