ABSTRACT
We hypothesized that in individuals with previous SARS-CoV-2 infection, the first vaccine dose would work as a booster, eliciting a faster and more intense immune response. We herein describe antibody responses to the first and second doses of Gam-COVID-Vac (SPUTNIK V) vaccine in health personnel of Tucuman, Argentina, with previous COVID-19 and compared it with uninfected personnel. Individuals with anti-SARS-CoV-2 titers at baseline showed significantly higher responses to the first dose than people with no prior history of disease (p <0.0001), with titers higher to those registered after the second dose in the control group, representing a clear secondary antibody response. This suggests that a single dose of SPUTNIK V for people with previous SARS-CoV-2 infection could contribute to a better use of available doses. One-Sentence SummaryFirst vaccine dose in subjects with prior COVID19 elicits a higher antibody response than two doses in uninfected individuals
ABSTRACT
The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) first reported in Wuhan has caused a global pandemic with dramatic health and socioeconomic consequences. The Coronavirus Disease 2019 (COVID-19) associated represents a challenge for health systems that had to quickly respond developing new diagnostic and therapeutic strategies. In the present work, we developed an "In House" ELISA with high sensitivity (92.2 %), specificity (100%) and precision (93.9%), with an area under the ROC curve (AUC) of 0.991, rendering the assay as an excellent serological test to correctly discriminate between SARS-COv-2 infected and non-infected individuals and study population seroprevalence. Among 758 patients evaluated for SARS-CoV-2 diagnosis in the province of Tucuman, Argentina, we found a Pearson correlation coefficient of 0.5048 between antibodies elicited against the RBD and the nucleocapsid (N) antigen. Additionally, 33.6% of individuals diagnosed with COVID-19 displayed mild levels of RBD-IgG antibodies, while 19% of the patients showed high antibody titers. Interestingly, patients with SARS-COV-2 infection over 60 years old elicited significantly higher levels of IgG antibodies against RBD compared to younger ones, while no difference was found between women and men. Surprisingly, individuals from a high altitude village displayed statistically significant higher and longer lasting anti-RBD antibodies compared to those from a city at a lower altitude, suggesting that a hypobaric hypoxia-adapted mechanism may act as a protective factor for COVID-19. To our knowledge, this is the first report correlating altitude with increased humoral immune response against SARS-Cov-2 infection.
