COVID-19 vaccines increase the overall rate of infection

C. Sacco, M. Del Manso, A. Mateo-Urdiales, M. Rota, D. Petrone, F. Riccardo, A. Bella, A. Siddu, Serena Battilomo, Valeria Proietti, P. Popoli, F. Menniti Ippolito, A. Palamara, S. Brusaferro, G. Rezza, P. Pezzotti, M. Fabiani. Effectiveness of BNT162b2 vaccine against SARS-CoV-2 infection and severe COVID-19 in children aged 5–11 years in Italy: a retrospective analysis of January–April, 2022. 2022. https://doi.org/10.1016/S0140-6736(22)01185-0

A retrospective analysis in Italy shows that fully and partly vaccinated children aged 5–11 years experienced positive vaccine effectiveness against SARS-CoV-2 infection.

A. Butt, H. Chemaitelly, A. Al Khal, P. Coyle, H. Saleh, A. Kaleeckal, A. Latif, R. Bertollini, A. Abou-Samra, L. Abu-Raddad. SARS-CoV-2 vaccine effectiveness in preventing confirmed infection in pregnant women.. 2021. https://doi.org/10.1172/JCI153662

A study of pregnant women finds that mRNA vaccines provide a high level of protection against confirmed SARS-CoV-2 infection.

A. Barchuk, A. Bulina, M. Cherkashin, N. Berezina, T. Rakova, D. Kuplevatskaya, D. Skougarevskiy, A. Okhotin. Gam-COVID-Vac, EpiVacCorona, and CoviVac effectiveness against lung injury during Delta and Omicron variant surges in St. Petersburg, Russia: a test-negative case–control study. 2022. https://doi.org/10.1186/s12931-022-02206-3

A test-negative case-control study shows that vaccines remained effective against lung injury during Delta and Omicron variant surges.

L. Bloomfield, S. Ngeh, G. Cadby, Kate Hutcheon, P. Effler. SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022. 2023. https://doi.org/10.3201/eid2906.230130

An Australian study finds that 3-dose vaccination provided positive vaccine effectiveness against infection and severe outcomes from the Omicron variant.

Porfirio Felipe Hernández Bautista, Concepción Grajales Muñiz, David Alejandro Cabrera Gaytán, Teresita Rojas Mendoza, Alfonso Vallejos Parás, Clara Esperanza Santacruz Tinoco, Julio Elias Alvarado Yaah, Yu-Mei Anguiano Hernández, Nancy Sandoval Gutiérrez, Leticia Jaimes Betancourt. Impact of vaccination on infection or death from COVID-19 in individuals with laboratory-confirmed cases: Case-control study. 2023. https://doi.org/10.1371/journal.pone.0265698

A case-control study indicates that COVID-19 vaccination served as a protective factor against symptomatic infection and mortality.

George N Okoli, Caitriona Murphy, Loretta Mak, Samuel M S Cheng, M. Peiris, B. Cowling. Estimates of SARS-CoV-2 vaccine effectiveness against outpatient medically attended SARS-CoV-2 infection from April 2023 through August 2024 in Hong Kong: A test-negative design study.. 2025. https://doi.org/10.1016/j.vaccine.2025.127687

A study in Hong Kong concludes that SARS-CoV-2 vaccines provided substantial protection against medically attended infection in both children and adults.

Covid-19, Vaccination Rates, Infection Rates, Death Rates and Behavioral Interventions: It’s Time to Cut the Bull!. 2022. https://doi.org/10.33140/ijcmer.01.01.03

An ecological analysis in Germany shows that less-vaccinated states had substantially higher infection and death rates than more-vaccinated states.

Robert C. Sinclair, R. Jeffrey Melton. COVID-19, Vaccination Rates, Infection Rates, Death Rates, and Behavioral Interventions: It’s Time to Cut the Bull!. 2022. https://doi.org/10.21203/rs.3.rs-1277705/v1

A duplicate publication of the German state analysis also shows higher infection rates in less-vaccinated regions.

Joe Kelly, Alison Judd. Coronavirus (COVID-19) infection rates and vaccination uptake in school pupils in England.. 2022. https://doi.org/10.23889/ijpds.v7i3.1914

An administrative data study in England finds that unvaccinated pupils had a significantly higher rate of reporting a positive test compared to vaccinated pupils.