{"doi":"10.7189/jogh.13.06004","title":"Differential COVID-19 infection rates in children, adults, and elderly: Systematic review and meta-analysis of 38 pre-vaccination national seroprevalence studies","abstract":"<h4>Background</h4>Debate exists about whether extra protection of elderly and other vulnerable individuals is feasible in COVID-19. We aimed to assess the relative infection rates in the elderly vs the non-elderly and, secondarily, in children vs adults.<h4>Methods</h4>We performed a systematic review and meta-analysis of seroprevalence studies conducted in the pre-vaccination era. We identified representative national studies without high risk of bias through SeroTracker and PubMed searches (last updated May 17, 2022). We noted seroprevalence estimates for children, non-elderly adults, and elderly adults, using cut-offs of 20 and 60 years (or as close to these ages, if they were unavailable) and compared them between different age groups.<h4>Results</h4>We included 38 national seroprevalence studies from 36 different countries comprising 826 963 participants. Twenty-six of these studies also included pediatric populations and twenty-five were from high-income countries. The median ratio of seroprevalence in elderly vs non-elderly adults (or non-elderly in general, if pediatric and adult population data were not offered separately) was 0.90-0.95 in different analyses, with large variability across studies. In five studies (all in high-income countries), we observed significant protection of the elderly with a ratio of <0.40, with a median of 0.83 in high-income countries and 1.02 elsewhere. The median ratio of seroprevalence in children vs adults was 0.89 and only one study showed a significant ratio of <0.40. The main limitation of our study is the inaccuracies and biases in seroprevalence studies.<h4>Conclusions</h4>Precision shielding of elderly community-dwelling populations before the availability of vaccines was indicated in some high-income countries, but most countries failed to achieve any substantial focused protection.<h4>Registration</h4>Open Science Framework (available at: https://osf.io/xvupr).","journal":"Journal of Global Health","year":2023,"id":12508,"datarank":0.5611057323797449,"base_score":2.772588722239781,"endowment":2.772588722239781,"self_citation_contribution":0.41588830833596724,"citation_network_contribution":0.1452174240437777,"self_endowment_contribution":0.41588830833596724,"citer_contribution":0.1452174240437777,"corpus_percentile":null,"corpus_rank":null,"citation_count":15,"citer_count":9,"citers_with_citation_signal":7,"citers_with_endowment":7,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.0643,"is_oa":true,"file_count":1,"downloads":9,"has_version_chain":false,"published_date":"2023-01-20","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":60994,"name":"Alexandre Apostolatos","orcid":null,"position":3,"is_corresponding":false},{"id":918,"name":"Despina G. Contopoulos‐Ioannidis","orcid":"0000-0002-1918-8918","position":5,"is_corresponding":false},{"id":148,"name":"John P. A. Ioannidis","orcid":"0000-0003-3118-6859","position":6,"is_corresponding":false},{"id":3829,"name":"Cathrine Axfors","orcid":"0000-0002-2706-1730","position":0,"is_corresponding":true}],"reference_count":72,"raw_metadata":{"citation_network_status":"fetched"},"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":[]}