{"doi":"10.1016/j.envres.2021.112342","title":"Change in age distribution of COVID-19 deaths with the introduction of COVID-19 vaccination","abstract":"<h4>Objectives</h4>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.<h4>Eligible data</h4>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).<h4>Main outcome measures</h4>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.<h4>Results</h4>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.<h4>Conclusions</h4>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.","journal":"Environmental Research","year":2022,"id":4900,"datarank":0.5456379239589579,"base_score":3.6375861597263857,"endowment":3.6375861597263857,"self_citation_contribution":0.5456379239589579,"citation_network_contribution":0.0,"self_endowment_contribution":0.5456379239589579,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":37,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.2861,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-03-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":4553,"name":"Angelo Maria Pezzullo","orcid":"0000-0002-8252-4654","position":1,"is_corresponding":false},{"id":4554,"name":"Leonardo Villani","orcid":"0000-0001-9375-8731","position":2,"is_corresponding":false},{"id":4555,"name":"Francesco Andrea Causio","orcid":"0000-0002-6545-3196","position":3,"is_corresponding":false},{"id":3829,"name":"Cathrine Axfors","orcid":"0000-0002-2706-1730","position":4,"is_corresponding":false},{"id":3357,"name":"Stefania Boccia","orcid":"0000-0002-1864-749X","position":6,"is_corresponding":false},{"id":148,"name":"John P. A. Ioannidis","orcid":"0000-0003-3118-6859","position":7,"is_corresponding":false},{"id":918,"name":"Despina G. Contopoulos‐Ioannidis","orcid":"0000-0002-1918-8918","position":8,"is_corresponding":false},{"id":4552,"name":"Roberta Pastorino","orcid":"0000-0001-5013-0733","position":0,"is_corresponding":true}],"reference_count":35,"raw_metadata":null,"created_at":"2026-03-01T18:20:47.508186Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}