As compared to people who never had COVID-19 infection, a single dose of vector-based vaccine portrayed higher neutralizing antibody response and helps to develop protective immunity in people who were exposed to SARS-CoV-2 infection, a study issued in the International Journal of Infectious Diseases disclosed. This study by Mitnala Sasikala et al. examined the immunological memory in previously SARS-CoV-2 infected healthcare workers after a dose of vaccine.

A total of 280 healthcare workers were enrolled following a written informed approval. They were grouped as previously infected and no prior exposure (RT-PCR positive and negative). Blood samples were collected at the baseline and after vaccination dose for numbering neutralizing antibodies via chemiluminescence and memory T- and B-cells by flow cytometry.

As found, previously infected individuals had elevated memory T and B-cell responses: antibody response; cluster of differentiation 4 (CD4) memory T-cells: central memory CCR7+ CD45RA-, effector memory CCR7-/CD45RA-; total CD8+ T-cells; CD8+ naïve T-cells CCR7+CD45RA+ and memory B-cells CD20+CD27+ than individuals with no history of COVID-19 exposure.

Thus, a single-dose vaccination induces higher neutralizing antibody response and protective immunity in people recovered from coronavirus infection vs. people with no previous exposure.