1. Protection of homologous and heterologous boosters after primary schemes of rAd26-rAd5, ChAdOx1 nCoV-19 and BBIBP-CorV during the omicron outbreak in adults of 50 years and older in Argentina: a test-negative case–control studyResearch in context
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Soledad González, Santiago Olszevicki, Alejandra Gaiano, Martín Salazar, Lorena Regairaz, Ana Nina Varela Baino, Erika Bartel, Teresa Varela, Veronica V. González Martínez, Santiago Pesci, Lupe Marín, Juan Ignacio Irassar, Leticia Ceriani, Enio Garcia, Nicolás Kreplak, Elisa Estenssoro, and Franco Marsico
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Vaccination ,Public aspects of medicine ,RA1-1270 - Abstract
Summary: Background: After primary vaccination schemes with rAd26-rAd5 (Sputnik V), ChAdOx1 nCoV-19, BBIBP-CorV or heterologous combinations, the effectiveness of homologous or heterologous boosters (Sputnik V, ChAdOx, Pfizer-BioNTech, Moderna) against SARS-CoV-2 infections, hospitalisations and deaths has been scarcely studied. Methods: Test-negative, case–control study, conducted in Argentina during omicron BA.1 predominance, in adults ≥50 years old tested for SARS-CoV-2 who had received two or three doses of COVID-19 vaccines. Outcomes were COVID-associated infections, hospitalisations and deaths after administering mRNA and vectored boosters, < or ≥60 days from the last dose. Findings: Of 422,124 individuals tested for SARS-CoV-2, 221,993 (52.5%) tested positive; 190,884 (45.2%) and 231,260 (54.8%) had received 2-dose and 3-dose vaccination schemes, respectively. The 3-dose scheme reduced infections, hospitalisations and death (OR 0.81 [0.80–0.83]; 0.28 [0.25–0.32] and 0.25 [0.22–0.28] respectively), but protection dropped after 60 days to 1.04 [1.01–1.06]; 0.52 [0.44–0.61] and 0.38 [0.33–0.45]). Compared with 2-dose-schemes, homologous boosters after primary schemes with vectored-vaccines provided lower protection against infections < and ≥60 days (0.94 [0.92–0.97] and 1.05 [1.01–1.09], respectively) but protected against hospitalisations (0.30 [0.26–0.35]) and deaths (0.29 [0.25–0.33]), decreasing after 60 days (0.59 [0.47–0.74] and 0.51 [0.41–0.64], respectively). Heterologous boosters protected against infections (0.70 [0.68–0.71]) but decreased after 60 days (1.01 [0.98–1.04]) and against hospitalisations and deaths (0.26 [0.22–0.31] and 0.22 [0.18–0.25], respectively), which also decreased after 60 days (0.43 [0.35–0.53] and 0.33 [0.26–0.41], respectively). Heterologous boosters protected against infections when applied
- Published
- 2023
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