Vaccination and COVID-19 infection among adults aged 45 years and above in a North-Eastern state of India

BACKGROUND: In response to this coronavirus disease 2019 (COVID-19) pandemic, vaccines reaching the predetermined levels of safety and efficacy were rolled out for use under emergency use approval/listing (EUA/EUL). The government of India has introduced three vaccines for emergency use as of today. AIM: The study was conducted to evaluate the association between the Covishield vaccine and COVID-19 infection among adults (≥45 years) who undergo reverse transcription–polymerase chain reaction (RT-PCR) COVID-19 testing. METHODS: The study was conducted in a dedicated COVID-19 hospital in a north-eastern state of India among adults aged 45 years and above, who underwent RT-PCR testing. Cases were those who tested positive for RT-PCR and controls were those who were RT-PCR negative during the same period. A structured questionnaire was used to collect relevant data pertaining to socio-demographic profile, symptoms of COVID-19, vaccination status, co-morbidities, etc. Multiple logistic regression was used to calculate the odds ratio (OR) to find the association between vaccination and COVID-19 infection. RESULTS: A total of 116 participants, 45 years and above were interviewed in the study. It was found that cases were more likely to have symptoms (48% vs. 6.9%, P value = <0.005) and have history of positive family member (89.7% vs. 72.4%, P value = 0.018) than controls. The odds of having COVID-19 infection were OR 12.60 (95% confidence interval (CI) 4.03-39.34) for those that have symptoms and OR 6.07 (95% CI 1.90-19.34) for unvaccinated individuals. CONCLUSIONS: Covishield vaccine protected individuals against COVID-19 infection with the risk of getting the infection being significantly lower in vaccinated individuals. Relevance for Patients: COVID-19 vaccination prevents the infection and addresses misconceptions about the vaccine.