Longitudinal and comparative analysis of humoral response upon COVID-19 vaccination

Romero-Pinedo, S.; Quesada, M.; Alvarez-Fernandez, S.; Olmo, A.; Abia, D.; Alarcon, B.; Delgado, P.

The emergence of COVID-19 has led to a worldwide challenge for the rapid development of vaccines. Several types of safe and effective vaccines have been available in a time frame never seen before. Comparative studies to know the extent of protection and the immune response elicited by the different vaccines are of outstanding utility. Here, as a correlate for protection, we perform a comparative study of the humoral response to three vaccines, ChAdOx1 (Oxford-AstraZeneca), mRNA-1273 (Moderna), and BNT162b2 (Pfizer-BioNTech) by applying a flow cytometry-based highly sensitive method that we had previously developed. We have found that mRNA vaccines (mRNA-1273 and BNT162b2) induce a stronger humoral response that lasts for at least 6 months after vaccination. We also show that only one dose of BNT162b2 is enough to achieve the maximum response in seropositive pre-vaccination donors.