Humoral immune response to COVID-19 vaccine in health care workers and the factors influencing it during vaccine drive - A cross-sectional study

• Author Details:   
• Sarwat Fatima ^*
• Deepika Handa

Background: The COVID-19 vaccine drive by the public healthcare system had several safety and efficacy concerns in the minds of health care workers and common man for several vague reasons.

Objective: In this context; the study was planned to determine the humoral immune response in the vaccine recipients of the first indigenously prepared vaccines in India [Covaxin & Covishield]. And, to know the influence of various factors on it. Lastly, to note the adverse events reported by the recipients if any.

Materials and Methods: A cross-sectional point prevalence study with simple convenient sampling method was designed. Baseline data on demographics, presence of comorbid conditions, vaccination details, adverse events to vaccine and information on presence of COVID-19 disease in the past 3-6 months was obtained from participants using a validated questionnaire. Institutional ethical clearance was obtained. The participants’ inclusion and exclusion criteria were established. SARS-CoV-2 IgG antibody was determined using ELFA method. Antibody index was estimated and used for interpretation of the test results. Statistical R software was used for data analysis.

Results: of the 86 participants, 84 were found eligible for enrollment. Male to female ratio was 0.9:1. The study participants were in the age group from 20-80 years. Around 29/84[34.52%] had comorbid conditions and the commonest comorbid conditions was hypertension. Overall, 72/84 [86%] of the HCWs were seropositive following vaccination. Greater number of fully vaccinated HCWs 60/62 [97%] were seropositive than partially vaccinated 12/22 [54%] with a p value of 0.001 and their corresponding antibody index was also higher. Among the various variables studied age, gender and presence of comorbid conditions the last one had a positive impact on seropositivity and antibody index values. Mild adverse events following vaccination were noted in majority. However, the antibody index was higher for them than in participants with no adverse events.

Conclusion: Our study highlights the efficacy and safety of vaccine by demonstrating seroconversion in 86% of the recipients and clears the vaccine hesitancy from the minds of HCWs and common man as well.