{"doi":"10.1016/j.ijid.2024.107300","title":"Natural immunity and protection against variants in South African children through five COVID-19 waves: A prospective study","abstract":"OBJECTIVES: Children have been largely spared from serious disease through the COVID-19 pandemic despite a high exposure to SARS-CoV-2. Antibody responses to exposure and their role in protecting children from subsequent variant infection remain poorly understood. METHODS: This is a prospective cohort study of children in a South African community through ancestral/Beta/Delta/Omicron BA.1/BA.2 and BA.4/BA.5 SARS-CoV-2 waves (March 2020-October 2022). Health seeking behavior/illness was recorded and postwave serum samples measured for immunoglobulin (Ig) G to spike (S) (CoV2-S-IgG) by electrochemiluminescent immunosorbent assay. To estimate the protective CoV2-S-IgG threshold levels, logistic functions were fit to describe the correlation of CoV2-S-IgG measured before a wave and the probability for seroconversion/boosting thereafter. RESULTS: Despite little disease, 125 per 366 (34.2%) children (median age 6.7 years [interquartile range 5.99-7.4 years]) were seropositive after wave I, rising to 53.6%, 76.0%, and 96.2% and 99.2% after waves II (Beta), III (Delta), and IV and V (Omicron variants), respectively. CoV2-S-IgG induced by natural exposure protected against subsequent SARS-CoV-2 infection, with the greatest protection for Beta and least for Omicron. The levels of IgG specific for ancestral S antigen that provided a 50% protective threshold for the subsequent wave were lowest for the Beta and highest for the Omicron BA.1/BA.2 wave. In the multivariate analysis, maternal seropositivity (adjusted odds ratio = 2.57 [95% confidence interval: 1.72-3.82]) was strongly associated with child seropositivity. CONCLUSION: Children responded robustly to successive waves of SARS-CoV-2, mounting IgG responses to S antigen that were protective against subsequent waves. In the absence of vaccination, almost all children were seropositive after wave V but none were hospitalized, suggesting that natural immunity alone may be sufficient to protect children in a pandemic setting.","journal":"International Journal of Infectious Diseases","year":2024,"id":472426,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9441,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":242153,"name":"Lesley Workman","orcid":"0000-0002-3433-6106","position":1,"is_corresponding":false},{"id":449292,"name":"Rae MacGinty","orcid":"0000-0002-7601-2994","position":2,"is_corresponding":false},{"id":679366,"name":"Maresa Botha","orcid":null,"position":3,"is_corresponding":false},{"id":659201,"name":"Marina Johnson","orcid":null,"position":4,"is_corresponding":false},{"id":871034,"name":"Adam Hunt","orcid":"0000-0001-5075-6904","position":5,"is_corresponding":false},{"id":871825,"name":"Tiffany Burd","orcid":null,"position":6,"is_corresponding":false},{"id":242133,"name":"Mark P. Nicol","orcid":"0000-0002-1366-4805","position":7,"is_corresponding":false},{"id":105090,"name":"Stefan Flasche","orcid":"0000-0002-5808-2606","position":8,"is_corresponding":false},{"id":105074,"name":"Billy J. Quilty","orcid":"0000-0002-9094-3728","position":9,"is_corresponding":false},{"id":579514,"name":"David Goldblatt","orcid":"0000-0002-0769-5242","position":10,"is_corresponding":false},{"id":5182,"name":"Heather J. Zar","orcid":"0000-0002-9046-759X","position":0,"is_corresponding":true}],"reference_count":27,"raw_metadata":null,"created_at":"2026-07-19T02:05:53.032464Z","pmid":"39547328","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":[]}