A single dose of COVID-19 vaccine was 82% effective in preventing deaths while two doses were 95% effective, an analysis of data on Tamil Nadu police personnel has indicated.
Data on vaccination of police personnel and COVID-19 deaths during the second wave was used to estimate the incidence of deaths among vaccinated and unvaccinated police personnel in the study ‘COVID-19 vaccine effectiveness in preventing deaths among high-risk groups in T.N’. It was taken up by the police department, the Indian Council of Medical Research-National Institute of Epidemiology (ICMR-NIE) and Christian Medical College, Vellore.
The police department has been documenting vaccination of its workforce and COVID-19 deaths during the second wave along with details of the date of hospitalisation and vaccination. There were 1,17,524 personnel working with the police department in the State. Between February 1 and May 14, 32,792 people received one dose of COVID-19 vaccine and 67,673 received both doses, while 17,059 were unvaccinated, according to the study that was published in the
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A total of 31 deaths due to COVID-19 were reported among these police personnel between April 13 and May 14. Of them, four were fully vaccinated, seven had received one dose of vaccine, and the rest 20 were unvaccinated.
The incidence of deaths among the vaccinated with zero, one and two doses were 1.17, 0.21 and 0.06 per 1,000 police personnel respectively.
Compared to unvaccinated individuals, the relative risk of COVID-19 deaths among those receiving one and two doses was 0.18 and 0.05 respectively. The vaccine effectiveness in preventing deaths with one and two doses was 82% and 95% respectively, it pointed out.
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Even a single dose helps
The analysis indicated that COVID-19 vaccination, even with a single dose, was effective in preventing deaths. It is necessary to increase coverage of COVID-19 vaccines — regardless of the type — to reduce mortality in current as well as future waves of the pandemic.
Manoj V. Murhekar, director of ICMR-NIE and one of the authors, said in a written response that the study indicated a vaccine effectiveness of 82% in preventing deaths with a single dose. “Similar estimates of vaccine effectiveness against severe disease with single dose have been documented in other countries. There is growing evidence now available that a single dose of vaccination can prevent severe outcomes compared with unvaccinated individuals,” he said.
More studies were being taken up to study vaccine effectiveness.
“ICMR is conducting a multi-centric case control study in 11 sites to estimate COVID-19 vaccine effectiveness against severe disease and variants of concern. ICMR-NIE, along with the Greater Chennai Corporation, is conducting a study in Chennai to estimate vaccine effectiveness,” he stated.
Anoop Jaiswal, V. Subburaj of the police department, Jeromie Wesley Vivian Thangaraj of ICMR-NIE and Jayaprakash Muliyil of CMC were the other authors.