2026-06-14T03:51:06Zhttps://repisalud.isciii.es/rest/oai/request

oai:repisalud.isciii.es:20.500.12105/158302024-09-27T16:48:45Zcom_20.500.12105_2052com_20.500.12105_2051col_20.500.12105_19608

00925njm 22002777a 4500 dc Monge Corella, Susana author Rojas-Benedicto, Ayelén author Olmedo, Carmen author Martín-Merino, Elisa author Mazagatos, Clara author Limia, Aurora author Sierra, María José author Larrauri, Amparo author Hernán, Miguel A author IBERCovid author Gomez-Barroso, Diana author 2023-02-08 Background: Single-dose vaccination was widely recommended in the pre-Omicron era for persons with previous SARS-CoV-2 infection. The effectiveness of a second vaccine dose in this group in the Omicron era is unknown. Methods: We linked nationwide population registries in Spain to identify community-dwelling individuals aged 18-64, with a positive SARS-CoV-2 test before single-dose mRNA vaccination (mRNA-1273 or BNT162b2). Every day between 3 January and 6 February 2022 we matched 1:1 individuals receiving a second mRNA vaccine dose and controls on sex, age, province, first dose type and time, month of primary infection, and number of previous tests. We then estimated Kaplan-Meier risks of confirmed SARS-CoV-2 reinfection. We performed a similar analysis in a Delta-dominant period, between 19 July and 30 November 2021. Results: In the Omicron period, estimated effectiveness (95% CI) of a second dose was 62.2% (58.2-66.4%) 7-34 days after administration, similar across groups defined by age, sex, type of first vaccine, and time since the first dose. Estimated effectiveness was 65.4% (61.1-69.9%) for mRNA-1273 and 52.0% (41.8-63.1%) for BNT162b2. Estimated effectiveness was 78.5% (67.4-89.9%), 66.1% (54.9-77.5%), and 60.2% (55.5-64.8%) when primary infection had occurred in the Delta, Alpha, and pre-Alpha periods, respectively. In the Delta period, the estimated effectiveness of a second dose was 8.8% (-55.3% to 81.1%). Conclusions: Our results suggest that, over 1 month after administration, a second dose of mRNA vaccine increases protection against SARS-CoV-2 reinfection with the Omicron variant among individuals with single-dose vaccination and previously infected with another variant. Clin Infect Dis. 2023 Feb 8;76(3):e367-e374. 10.1093/cid/ciac429 1537-6591 Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 35687580 http://hdl.handle.net/20.500.12105/15830 COVID-19 Omicron SARS-CoV-2 Effectiveness Vaccines Effectiveness of a Second Dose of an mRNA Vaccine Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Omicron Infection in Individuals Previously Infected by Other Variants