RESUMO
BackgroundThe emergence of new COVID-19 variants of concern coupled with a global inequity in vaccine access and distribution, prompted many public health authorities to circumvent the vaccine shortages by altering vaccination protocols and prioritizing high-risk individuals. Those with previous COVID-19 infection may have not been prioritized due to existing humoral immunity. ObjectiveWe aim to study the association between previous COVID-19 infection and antibody levels after COVID-19 vaccination. MethodsA serological analysis to measure SARS-CoV-2 IgG, IgA and neutralizing antibodies was performed on individuals who received one or two doses of either BNT162b2 or ChAdOx1 vaccines in Kuwait. Generalized linear regression models adjusted for individual characteristics and comorbidities were fitted to study the average levels of IgG and neutralizing antibodies in vaccinated individuals based who had previous COVID-19 infection compared to those who had not. ResultsA total of 1025 individuals were recruited. The mean levels of IgG, IgA and neutralizing antibodies were higher in vaccinated subjects with previous COVID-19 infection when compared with those vaccinated without previous COVID-19 infection. Regression analysis showed a steeper slope of decline for IgG in vaccinated individuals without previous COVID-19 infection in comparison with vaccinated individuals with previous COVID-19 infection. ConclusionPrevious COVID-19 infection appears to elicit robust and sustained levels of SARS-CoV-2 antibodies in vaccinated individuals. Given the inconsistent supply of COVID-19 vaccines in many countries due to the global inequity, our results point towards wider vaccination plans to especially cover individuals without previous COVID-19 infection.
RESUMO
The emergence of effective vaccines for COVID-19 has been welcomed by the world with great optimism. Given their increased susceptibility to COVID-19, the question arises whether individuals with type-2 diabetes mellitus (T2DM) and other metabolic conditions can respond effectively to the mRNA-based vaccine. We aimed to evaluate the levels of anti-SARS-CoV-2 IgG and neutralizing antibodies in people with T2DM and/or other metabolic risk factors (hypertension and obesity) compared to those without. This study included 262 people that took two doses of BNT162b2 (Pfizer-BioNTech) mRNA vaccine. Both T2DM and non-diabetic individuals had a robust response to vaccination as demonstrated by their high antibody titers. However, both SARS-CoV-2 IgG and neutralizing antibodies titers were lower in people with T2DM. Their levels were 154{+/-}49.1 vs. 138{+/-}59.4BAU/mL for IgG and 87.1{+/-}11.6 vs. 79.7{+/-}19.5% for neutralizing antibodies in individuals without diabetes compared to those with T2DM, respectively. In a multiple linear regression adjusted for individual characteristics, comorbidities, previous COVID-19 infection and duration since second vaccine dose, diabetics had 13.86 BAU/ml (95%CI: -27.08 to -0.64BAU/ml, p=0.041) less IgG antibodies and 4.42% (95%CI: -8.53 to -0.32%, p=0.036) less neutralizing antibodies than non-diabetics. Hypertension and obesity did not show significant changes in antibody titers. Taken together, both type-2 diabetic and non-diabetic individuals elicited strong immune responses to SARS-CoV-2 BNT162b2 mRNA vaccine; nonetheless, lower levels were seen in people with diabetes. Continuous monitoring of the antibody levels might be a good indicator to guide personalized needs for further booster shots to maintain adaptive immunity.
