To boost or not? Serum anti-COVID IgG in double vaccinated MBBS students: a cross-sectional study

Background: Aim of the study was to estimate the prevalence of sero-positivity i.e. serum anti-covid IgG >1.4 AU/ml in MBBS students of our Institute. Methods: This study was carried out on 75 MBBS students of our institute (10% of 750 MBBS students of Amaltas institute of Medical Sciences Dewas M.P. India) during period of August 2022 to November 2022. All serum anti-covid IgG titres above 1.4 AU/ml were considered sero-positive and the prevalence of sero-positivity was calculated. MBBS students were asked to fill out a questionnaire regarding their clinical history of testing positive for covid, exposure to COVID-19 patients, their covid appropriate behavior, etc. After obtaining informed consent, 4 ml venous blood samples were collected for determining serum anti-covid IgG titre on Chemiluminescence analyzer. 75 MBBS students divided into 2 groups � those who completed between 6-9 months and those who have completed more than 9 months after the 2nd dose of vaccine. The mean serum anti-covid IgG titre was compared. Results: The prevalence of sero-positivity was 94.66% calculated in MBBS students of our institute. The total antibody sero-positivity was higher in males (98.11%) than in females (86.36). The duration after 2nd dose of vaccine; over the time 6-9 months serum anti-covid IgG titre significantly high but after more than 9 months serum anti covid IgG titre significantly decline (p<0.001) and significant correlation was found between duration after 2nd dose of vaccine and serum anti-covid IgG titres (p<0.001). Conclusions: This study; strongly recommended the need for booster doses for long-duration protection against COVID-19 re-infection and its emerging new variants.