Comparative Analysis of Three COVID-19 Vaccines in Indian Metros

Background

This study evaluates COVID-19 vaccination coverage, vaccine effectiveness against SARS-CoV-2 variants, and associated health consequences in the five most important Indian metropolitan cities: Delhi, Mumbai, Bangalore, Kolkata, and Chennai.

Methods and Materials

A descriptive analytical approach was applied using reported data from the Ministry of Health and Family Welfare (MoHFW) and the Indian Council of Medical Research (ICMR). Indicators involved city-level full vaccination coverage (December 2022), vaccine types administered (Covishield, Covaxin, Sputnik V), variant-specific vaccine effectiveness (Original, Alpha, Delta, Omicron), age-wise mortality changes pre/post vaccination, and outcomes thru dosing strategy (single, double, booster) measured through reductions in infection, hospitalization, and mortality.

Results

Full vaccination coverage was reliably high: 82.5% in Delhi, Mumbai, and Bangalore; 82.3% in Kolkata; and 82.0% in Chennai. Covishield and Covaxin were used in all cities, with Sputnik V additionally in Delhi. Effectiveness was highest against the original strain (Covishield 76.2%, Covaxin 78.5%, Sputnik V 79.4%) and lowest against Omicron (45.3%, 42.7%, 46.1%). Mortality fell markedly after vaccination across age groups (reductions ~76.6%–78.6%). Strategy comparisons showed modest benefits with single-dose coverage (62%) versus stronger improvements with double-dose vaccination (82%), while boosters (42% coverage) provided the greatest reductions in infection, hospitalization, and mortality.

Conclusion

High metropolitan vaccination coverage was associated with substantial reductions in mortality and improved outcomes, but declining effectiveness against newer variants especially Omicron supports the need for adaptive strategies. Completing the prime series and expanding booster uptake, supported by continuous effectiveness monitoring, are key to sustaining urban protection.