Determinants of COVID-19 Breakthrough Infections and Severity in ChAdOx1 nCoV-19-Vaccinated Priority Groups.

The current analysis is a part of an ongoing observational study that began in February 2021 in the Sir Sunder Lal Hospital (Varanasi, Uttar Pradesh) in northern India and is expected to continue until June 2022. This analysis aimed to delineate the clinical presentation and risk factors of occurrence and severity of COVID-19 in vaccinated individuals. The study enrolled health-care workers and the elderly receiving the COVID-19 vaccine at one of three centers linked to the study hospital.

Persistent Health Issues, Adverse Events, and Effectiveness of Vaccines during the Second Wave of COVID-19: A Cohort Study from a Tertiary Hospital in North India.

There is paucity of real-world data on COVID-19 vaccine effectiveness from cohort designs. Variable vaccine performance has been observed in test-negative case-control designs. There is also scarce real-world data of health issues in individuals receiving vaccines after prior COVID-19, and of adverse events of significant concern (AESCs) in the vaccinated.

Occurrence of COVID-19 in priority groups receiving ChAdOx1 nCoV-19 coronavirus vaccine (recombinant): A preliminary analysis from north India.

The ChAdOx1 nCoV-19 vaccine (Oxford University-Astra Zeneca) has demonstrated nearly 70% efficacy against symptomatic COVID-19 in trials and some real-world studies. The vaccine was the first to be approved in India in early January 2021 and is manufactured by the Serum Institute of India. Favorable short-term safety data of the vaccine in India in a real-world setting has been recently demonstrated.