Effectiveness of the ChAdOx1 nCoV-19 Coronavirus Vaccine (CovishieldTM) in Preventing SARS-CoV2 Infection, Chennai, Tamil Nadu, India, 2021

• Published in: Vaccines (Basel) Vol. 10; no. 6; p. 970
• Main Authors: Murali, Sharan, Sakthivel, Manikandanesan, Pattabi, Kamaraj, Venkatasamy, Vettrichelvan, Thangaraj, Jeromie Wesley Vivian, Shete, Anita, Varghese, Alby John, Arjun, Jaganathan, Kumar, Chethrapilly Purushothaman Girish, Yadav, Pragya D, Sahay, Rima, Majumdar, Triparna, Dudhmal, Manisha, Sivalingam, Azhagendran, Dhanapal, Sudha Rani, Durai Samy, Augustine, Radhakrishnan, Vijayaprabha, Muni Krishnaiah, Murali Mohan, Arunachalam, Suresh, Gandhi, Punita Muni Krishna, Govindasamy, Elavarasu, Chinnappan, Prabhakaran, Sekar, Dhana Priya Vadhani, Marappan, Prakash, Pounraj, Ezhil, Ganeshkumar, Parasuraman, Jagadeesan, Murugesan, Narnaware, Manish, Bedi, Gagandeep Singh, Kaur, Prabhdeep, Murhekar, Manoj
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 17-06-2022; MDPI
• Subjects: Age; AZD 1222; ChAdOx1 nCoV-19; Coronaviruses; COVID-19; COVID-19 vaccines; Covishield; Genomic analysis; Households; Immunization; SARS-CoV-2 inactivated vaccines; Severe acute respiratory syndrome coronavirus 2; vaccine effectiveness; Vaccines; Viral diseases; Tamil Nadu India; India
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines10060970

We estimated the effectiveness of two doses of the ChAdOx1 nCoV-19 (Covishield) vaccine against any COVID-19 infection among individuals ≥45 years in Chennai, Tamil Nadu, India. A community-based cohort study was conducted from May to September 2021 in a selected geographic area in Chennai. The estimated sample size was 10,232. We enrolled 69,435 individuals, of which 21,793 were above 45 years. Two-dose coverage of Covishield in the 18+ and 45+ age group was 18% and 31%, respectively. Genomic analysis of 74 out of the 90 aliquots collected from the 303 COVID-19-positive individuals in the 45+ age group showed delta variants and their sub-lineages. The vaccine’s effectiveness against COVID-19 disease in the ≥45 age group was 61.3% (95% CI: 43.6–73.4) at least 2 weeks after receiving the second dose of Covishield. We demonstrated the effectiveness of two doses of the ChAdOx1 vaccine against the delta variant in the general population of Chennai. We recommend similar future studies considering emerging variants and newer vaccines. Two-dose vaccine coverage could be ensured to protect against COVID-19 infection.