Abstract
Neutralizing antibodies (NAbs) can be indicators of collective immunity, vaccine efficacy, and the longevity of the humoral response. This study aimed to compare reactogenicity and NAbs generated by three different COVID-19 vaccine platforms in individuals with and without prior COVID-19. 336 individuals vaccinated (112 with CoronaVac [inactivated virus], 112 with BNT162b2 [messenger RNA], and 112 with Ad5-nCoV [non-replicating viral vector]) were included. NAbs were quantified with the cPass SARS-CoV-2 kit. Individuals immunized with the Ad5-nCoV showed higher reactogenicity than those immunized with the other vaccines (p < 0.001). The BTN162b2 vaccine-induced NAbs with higher inhibition capacity than the other platforms in the first dose. In individuals without prior COVID-19, the Ad5-nCoV vaccine generated lower NAbs against SARS-CoV-2 than those induced by two doses of the BTN162b2 (Ad5-nCoV 72.10 [55.6-93.4] vs. BTN162b2 98.41 [98.16-98.56], p < 0.0001). One individual did not generate NAbs (0.89%) after a complete immunization with CoronaVac; in BTN162b2, all generated these antibodies, and in the Ad5-nCoV group, four individuals (3.57%) did not generate NAbs. Comorbidities, gender, age, and reactogenicity did not significantly influence the generation of NAbs (p > 0.05); however, a history of COVID-19 before vaccination was associated with antibodies with greater neutralizing capacity after the first dose (p < 0.01). In conclusion, the mRNA vaccine (BTN162b2) had a remarkable better ability to produce NAbs and lower reactogenicity than the other platforms, whereas the Ad5-nCov vaccine induced the lowest NAbs response in individuals without a history of COVID-19; therefore, we suggest that a booster could benefit these individuals.