{"doi":"10.1101/2021.11.16.21266360","title":"Impact of SARS-CoV-2 Vaccines on Covid-19 Incidence and Mortality in the United States","abstract":"ABSTRACT Background Despite safe and effective vaccines to prevent Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infections and disease, a substantial minority of the US remains resistant to getting vaccinated. It is imperative to know if expanding vaccination rates could reduce community-wide Coronavirus 2019 (COVID-19) disease, not just among those vaccinated. Methods Negative binomial models were used to estimate associations between U.S. county-level vaccination rates and county-wide COVID-19 incidence and mortality between April 23 rd and September 30 th , 2021. A two-week lag and a four-week lag were introduced to assess vaccination rate impact on incidence and mortality, respectively. Stratified analyses were performed for county vaccination rates 40%, and before and after Delta became the dominant variant. Findings Among 3,070 counties, each percentage increase in population vaccination rates reduced county-wide COVID-19 incidence by 0·9% (relative risk (RR) 0. 9910 (95% CI: 0·9869, 0·9952)) and mortality by 1·9% (RR 0·9807 (95% CI: 0·9745, 0·9823)). Among counties with vaccination coverage >40%, each percentage increase in vaccination rates reduced COVID-19 disease by 1·5%, RR 0·9850 (95% CI: 0·9793, 0·9952) and mortality by 2·7% (RR 0·9727 (95% CI: 0·9632, 0·9823)). These associations were not observed among counties with <40% vaccination rates. Increasing vaccination rates from 40% to 80% would have reduced COVID-19 cases by 45·4% (RR 0·5458 (95% CI: 0·4335, 0·6873)) and deaths by 67·0% (RR 0·3305 (95% CI: 0·2230, 0·4898)). An estimated 5,989,952 COVID-19 cases could have been prevented and 127,596 lives saved had US population vaccination rates increased from 40% to 80%. Interpretations Increasing U.S. SARS-CoV-2 vaccination rates results in population-wide reductions in COVID-19 incidence and mortality. Furthermore, increasing vaccination rates above 40% has protective effects among non-vaccinated persons. Given ongoing vaccine hesitancy in the U.S., increasing vaccination rates could better protect the entire community and potentially reach herd immunity. Funding National Cancer Institute","journal":"medRxiv","year":2021,"id":219617,"datarank":0.16479184330021646,"base_score":1.0986122886681096,"endowment":1.0986122886681096,"self_citation_contribution":0.16479184330021646,"citation_network_contribution":0.0,"self_endowment_contribution":0.16479184330021646,"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":0.948,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":345191,"name":"John D. Clemens","orcid":"0000-0002-6379-1052","position":1,"is_corresponding":false},{"id":265958,"name":"Zuo‐Feng Zhang","orcid":"0000-0002-4669-3995","position":2,"is_corresponding":false},{"id":818320,"name":"Timothy F. Brewer","orcid":"0000-0002-5615-1639","position":3,"is_corresponding":false},{"id":467482,"name":"Fang Fang","orcid":"0000-0002-3310-6456","position":0,"is_corresponding":true}],"reference_count":20,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T23:53:38.409982Z","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":[]}