Antibody Response to inactive SARS-CoV-2 vaccination in a cohort of elderly patients living with obesity

Abstract

Introduction Obesity and aging negatively affect the immune system and host defense mechanisms, increasing vulnerability to, worsening prognosis of infectious diseases and leading to vaccine failure. Our aim is to investigate the antibody response against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike antigens, and the risk factors affecting antibody levels in elderly people living with obesity (PwO) after inactive SARS-CoV-2 vaccine (CoronaVac) administration. Methods One hundred twenty-three consecutive elderly patients with obesity (age>65 years, Body Mass Index (BMI)>30kg/m2) and 47 adults with obesity (age 18-64 years, BMI>30kg/m2) admitted between August and November 2021 were enrolled. Seventy five non-obese elderly people (age >65 years, BMI 18.5-29.9 kg/m2) and 105 non-obese adults (age 18-64 years, BMI 18.5-29.9 kg/m2) were recruited from subjects who visited Vaccination Unit. SARS-CoV-2 spike-protein antibody titers were measured in patients with obesity and non-obese controls who received two doses of CoronaVac. Results SARS-CoV-2 levels of patients with obesity were found to be significantly lower than those of non-obese elderly individuals who had non-prior infection.There was no difference in SARS-CoV-2 levels between patients with obesity and non-obese individuals with prior infection. Age and SARS-CoV-2 level were found to be highly correlated in the correlation analysis in the group of elderly individuals (r:-0.184). In multivariate regression analysis, when SARS-CoV-2 IgG was regressed on age, sex, BMI, Type 2 Diabetes Mellitus (T2DM) and Hypertension (HT), HT was found to be an independant factor on SARS-CoV-2 level (β:-2730). Conclusion In non-prior infection group, elderly patients with obesity generated significantly reduced antibody titers against SARS-CoV-2 spike antigen after CoronaVac vaccine compared to non-obese people. It is anticipated that the results obtained will provide invaluable information about SARS-CoV-2 vaccination strategies in this vulnerable population. Antibody titers may be measured and booster doses should be delivered accordingly in elderly PwO for optimal protection.