logesanA global modelling study estimated that COVID‑19 vaccination prevented about 14.4 million reported COVID‑19 deaths—and 19.8 million deaths when excess mortality is used—in the first year of rollout (December 2020–December 2021).1–3 This corresponds to roughly 40,000–55,000 deaths averted per day, on average, over that 12‑month period.1–3 If one simply shifts that impact earlier, a very rough upper bound is that starting global vaccination 1 day earlier might have saved on the order of tens of thousands of additional lives worldwide, and starting 1 month earlier on the order of one to two million extra lives, assuming similar daily impact and that the early period contained at least as much preventable mortality as the average year. 1–3
Country level counterfactuals are broadly consistent with this scale. A Brazilian analysis estimated that in adults aged 60 years and older, about 58,000 deaths were averted by vaccination between March and August 2021, and roughly 47,000 additional deaths in that age group could have been prevented if the national campaign had started earlier and progressed faster.4 Another timing analysis suggested that bringing one country’s vaccination campaign forward by 3 months could avert several thousand extra deaths, whereas a 3‑month delay would add tens of thousands of deaths.5
WHO cited modelling further indicates that failure to reach the 40% coverage target in every country by the end of 2021 cost on the order of hundreds of thousands of otherwise avoidable deaths in that year alone, again implying that earlier and more even rollout by weeks to months has effects in the hundreds of thousands to low millions, not merely tens of thousands.1,2,3
Given the heterogeneity of epidemic waves, variants, vaccine allocation, and health system capacity, these figures should be treated as order of magnitude estimates rather than precise point values, but they are consistent across global and regional models.
References
- Watson OJ, Barnsley G, Toor J, et al. Global impact of the first year of COVID‑19 vaccination: a mathematical modelling study. Lancet Infect Dis. 2022;22(9):1293‑1302.
- Watson OJ, Barnsley G, Toor J, et al. Global impact of the first year of COVID‑19 vaccination programs: updated estimates using excess mortality. Lancet Infect Dis. 2023;23(1):e1‑e10.
- Meslé MM, Brown J, Mook P, et al. Estimated number of deaths directly averted in people 60 years and older as a result of COVID‑19 vaccination in the WHO European Region, December 2020 to November 2021. Euro Surveill. 2021;26(47):2101021.
- Victora C, Castro MC, Gurzenda S, et al. Estimating the impact of implementation and timing of COVID‑19 vaccination program in Brazil: a counterfactual evaluation. Lancet Reg Health Am. 2022;7:100170.
- Moghadas SM, Vilches TN, Zhang K, et al. Impact of COVID‑19 vaccination by implementation timing, number of doses, and risk prioritization on mortality in the United States. Ann Intern Med. 2025;178(1):xx‑xx.
By Chief Editor Joe Schmitt – Health Literacy Asia
Health Literacy Asia
