Efectividad de refuerzos homólogos y heterólogos luego de esquemas primarios con Sputnik V, Astra-Zeneca y Sinopharm durante el período omicron en adultos mayores de 50 años en la provincia de Buenos Aires / Effectiveness of homologous and heterologous boosters after primary regimens with Sputnik V, AstraZeneca, and Sinopharm during the omicron variant period in adults over 50 years old in the province of Buenos Aires

RESUMEN

Objetivo: Evaluar la efectividad de esquemas primarios de Sputnik V, Astra-Zeneca, Sinopharm o combinaciones heterólogas seguidos de refuerzos a vector viral (Sputnik V, Astra-Zeneca) o ARNm (Pfizer-BioNTech, Moderna) frente a infecciones, hospitalizaciones y muertes por SARS-CoV-2. Material y métodos: Estudio de casos y controles con test negativo realizado en la provincia de Buenos Aires, durante el predominio de ómicron BA.1, que incluyó individuos ≥ 50 años con test positivo para SARS-CoV-2 que habían recibido 2 o 3 dosis de vacunas. Se registraron infecciones, hospitalizaciones y muertes después de administrar refuerzos con Sputnik V, Astra-Zeneca o ARNm. Resultados: De 422 124 personas analizadas para SARS-Cov-2, 221 993 (52.5%) presentaron test positivos; 190 884 (45.2%) y 231.260 (54.8%) recibieron esquemas de vacunación de 2 y 3 dosis, respectivamente. Los esquemas primarios con Astra-Zeneca, Sputnik V o vector viral, combinados con un refuerzo a vector viral, mostraron protección contra infecciones (OR 0.94 [0.92 a 0.97]), hospitalizaciones (OR 0.30 [0.26 a 0.35]) y muertes (OR 0.29 [0.25 a 0.33]. Los esquemas primarios con Astra-Zeneca y Sputnik V más refuerzo de ARNm, o con Sinopharm más refuerzo de ARNm o vector viral otorgaron protección adicional contra infecciones (OR 0.70 [0.68 a 0.71]). Hubo un efecto protector frente a hospitalizaciones y muertes (OR 0.26 [0.22 a 0.31] y 0.22 [0.18 a 0.25]) en todos los casos. Conclusiones: Durante el predominio de ómicron, los refuerzos heterólogos con vacunas a vector viral y de ARNm, posteriores a los esquemas primarios de Sputnik V, Astra-Zeneca, Sinopharm o heterólogos, podrían proporcionar mejor protección y mayor duración del efecto contra la muerte en personas mayores de 50 años, en comparación con refuerzos homólogos

ABSTRACT

Objective: To evaluate the effectiveness of primary vaccination regimens involving Sputnik V, Astra-Zeneca, Sinopharm, or heterologous combinations followed by viral vector boosters (Sputnik V, As-traZeneca) or mRNA boosters (Pfizer-BioNTech, Moderna) against infections, hospitalizations and deaths caused by SARS-CoV-2. Material and methods: Case-control studies with negative tests conducted in the Buenos Aires province during the Omicron BA.1 predominance. The study included patients ≥ 50 years of age, who tested positive for SARS-CoV-2 and had received two or three doses of vaccines. Infections, hospitalizations, and deaths were registered following the administration of Sputnik V, AstraZeneca, or mRNA boosters. Findings: Out of 422 124 people tested for SARS-Cov-2, 221 993 (52.5%) had positive test results; 190,884 (45.2%) and 231 260 (54.8%) received two-dose and three-dose vaccination schemes, respectively. Primary regimens with AstraZeneca, Sputnik V, or viral vector, combined with a viral vector booster demonstrated protection against infections (OR 0.94 [0.92 to 0.97]), hospitalizations (OR 0.30 [0.26 to 0.35]) and deaths (OR 0.29 [0.25 to 0.33]. Primary regimens with AstraZeneca and Sputnik V combined with mRNA boosters, as well as pri-mary schemes with Sinopharm combined with mRNA or viral vectored boosters showed additional protection against infections (OR 0.70 [0.68 to 0.71]). There was a protective effect against hospi-talizations and deaths (OR 0.26 [0.22-0.31] and 0.22 [0.18 -0.25]) in all cases. Conclusions: During Omicron predominance, heterologous boosters with viral-vector and mRNA vaccines, administered after Sputnik V, AstraZeneca, Sinopharm, or heterologous primary regimens, could provide enhanced protection and prolonged effectiveness against mortality in individuals aged ≥ 50, compared to ho-mologous boosters