mRNA BNT162b Vaccine Elicited Higher Antibody and CD4 + T-Cell Responses than Patients with Mild COVID-19.

We compared the development and persistence of antibody and T-cell responses elicited by the mRNA BNT162b2 vaccine or SARS-CoV-2 infection. We analysed 37 post-COVID-19 patients (15 with pneumonia and 22 with mild symptoms) and 20 vaccinated subjects. Anti-Spike IgG and neutralising antibodies were higher in vaccinated subjects and in patients with pneumonia than in patients with mild COVID-19, and persisted at higher levels in patients with pneumonia while declining in vaccinated subjects. However, the booster dose restored the initial antibody levels. The proliferative CD4 + T-cell response was similar in vaccinated subjects and patients with pneumonia, but was lower in mild COVID-19 patients and persisted in both vaccinated subjects and post-COVID patients. Instead, the proliferative CD8 + T-cell response was lower in vaccinated subjects than in patients with pneumonia, decreased six months after vaccination, and was not restored after the booster dose. The cytokine profile was mainly T H 1 in both vaccinated subjects and post-COVID-19 patients. The mRNA BNT162b2 vaccine elicited higher levels of antibody and CD4 + T-cell responses than those observed in mild COVID-19 patients. While the antibody response declined after six months and required a booster dose to be restored at the initial levels, the proliferative CD4 + T-cell response persisted over time.