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. 2022 Mar;204(Pt C):112342.
doi: 10.1016/j.envres.2021.112342. Epub 2021 Nov 5.

Change in age distribution of COVID-19 deaths with the introduction of COVID-19 vaccination

Roberta Pastorino  1 , Angelo Maria Pezzullo  2 , Leonardo Villani  2 , Francesco Andrea Causio  2 , Cathrine Axfors  3 , Despina G Contopoulos-Ioannidis  4 , Stefania Boccia  5 , John P A Ioannidis  6
Affiliations

Change in age distribution of COVID-19 deaths with the introduction of COVID-19 vaccination

Roberta Pastorino et al. Environ Res. 2022 Mar.

Abstract

Objectives: Most countries initially deployed COVID-19 vaccines preferentially in elderly populations. We aimed to evaluate whether population-level vaccine effectiveness is heralded by an increase in the relative proportion of deaths among non-elderly populations that were less covered by vaccination programs.

Eligible data: We collected data from 40 countries on age-stratified COVID-19 deaths during the vaccination period (1/14/2021-5/31/2021) and two control periods (entire pre-vaccination period and excluding the first wave).

Main outcome measures: We meta-analyzed the proportion of deaths in different age groups in vaccination versus control periods in (1) countries with low vaccination rates; (2) countries with age-independent vaccination policies; and (3) countries with standard age-dependent vaccination policies.

Results: Countries that prioritized vaccination among older people saw an increasing share of deaths among 0-69 year old people in the vaccination versus the two control periods (summary proportion ratio 1.32 [95 CI% 1.24-1.41] and 1.35 [95 CI% 1.26-1.44)]. No such change was seen on average in countries with age-independent vaccination policies (1.05 [95 CI% 0.78-1.41 and 0.97 [95 CI% 0.95-1.00], respectively) and limited vaccination (0.93 [95 CI% 0.85-1.01] and 0.95 [95 CI% 0.87-1.03], respectively). Proportion ratios were associated with the difference of vaccination rates in elderly versus non-elderly people. No significant changes occurred in the share of deaths in age 0-49 among all 0-69 deaths in the vaccination versus pre-vaccination periods.

Conclusions: The substantial shift in the age distribution of COVID-19 deaths in countries that rapidly implemented vaccination predominantly among elderly provides evidence for the population level-effectiveness of COVID-19 vaccination and a favorable evolution of the pandemic towards endemicity with fewer elderly deaths.

Keywords: COVID-19; Death; Population data; Vaccination.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
Meta-analysis of proportion ratios (PR) of COVID-19 deaths in age 0–69 in the vaccination versus pre-vaccination control periods stratified according to three main categories 1) Low vaccination rates: countries with a proportion of vaccination with at least one dose <5% in the general population by the end of April 2021; 2) Age-independent policies: countries with early vaccination policies that vaccinated vulnerable groups regardless of age on January 15, 2021; 3) Standard age-dependent policies: remaining countries. PR > 1 implies a higher proportion of deaths accounted by 0–69 age group in the vaccination period versus pre-vaccination periods. Panel A: vaccination period versus entire pre-vaccination period. Panel B: vaccination period versus second wave pre-vaccination period.
Fig. 2
Fig. 2
Meta-analysis of proportion ratios (PR) of COVID-19 deaths in age 0–49 among 0–69 deaths in the vaccination versus pre-vaccination control periods stratified by three main categories 1) Low vaccination rates: countries with a proportion of vaccination with at least one dose <5% in the general population by the end of April 2021; 2) Age-independent policies: countries with early vaccination policies that vaccinated vulnerable groups regardless of age on January 15, 2021; 3) Standard age-dependent policies: remaining countries. PR > 1 implies a higher proportion of deaths accounted by 0–49 age group in the vaccination period versus pre-vaccination periods. Panel A: vaccination period versus entire pre-vaccination period. Panel B: vaccination period versus second wave pre-vaccination period.
Fig. 3
Fig. 3
Meta-regression of the logarithm of the proportion ratio of COVID-19 deaths in the 0–69 age group in the vaccination versus pre-vaccination periods as a function of the difference in the proportion of fully vaccinated people in the ≥70 versus 0–69 age strata (Panel A and B) and as a function of the difference in the proportion of vaccinated people with at least one dose in the ≥70 versus 0–69 age strata (Panel C and D).
See this image and copyright information in PMC

References

    1. Baden L.R., El Sahly H.M., Essink B., Kotloff K., Frey S., Novak R., et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N. Engl. J. Med. 2021;384(5):403–416. - PMC - PubMed
    1. Bajema K.L., Wiegand R.E., Cuffe K., Patel S.V., Iachan R., Lim T., et al. Estimated SARS-CoV-2 seroprevalence in the US as of september 2020. JAMA Intern Med. 2021;181(4):450–460. - PMC - PubMed
    1. Benjamin D.J., Berger J.O., Johannesson M., Nosek B.A., Wagenmakers E.J., Berk R., et al. Redefine statistical significance. Nat Hum Behav. 2018;2(1):6–10. doi: 10.1038/s41562-017-0189-z. Available from: - DOI - PubMed
    1. Bernal J.L., Andrews N., Gower C., Robertson C., Stowe J., Tessier E., et al. Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines on covid-19 related symptoms, hospital admissions, and mortality in older adults in England: test negative case-control study. BMJ. 2021:373. - PMC - PubMed
    1. Boehm E., Kronig I., Neher R.A., Eckerle I., Vetter P., Kaiser L. Novel SARS-CoV-2 variants: the pandemics within the pandemic. Clin. Microbiol. Infect. 2021;S1198–743X(21):262–267. - PMC - PubMed

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