A efetividade da imunização na redução de mortes em pacientes com doenças cardiovasculares com síndrome respiratória aguda grave por Covid-19 no Brasil: um estudo nacional de coorte retrospectiva

Abstract

Introduction: In Brazil, due to the high percentage of individuals with cardiovascular diseases (CVD) who developed Severe Acute Respiratory Syndrome from COVID-19 (SARS/COVID-19), it is still relevant to analyze the best interventions capable of reducing the severity and mortality of the disease. Despite the development of new drugs against COVID-19, vaccines are still the best option. To date, no Brazilian study has analyzed the effectiveness of immunization against COVID-19 in patients with CVD during the years 2021 and 2022. Therefore, the main objective of this study was to evaluate the effectiveness of immunization against COVID-19 in reducing deaths from SARS/COVID-19 in patients with CVD in Brazil. Methods: This was a national retrospective observational cohort. The target population consisted of individuals with CVD, hospitalized for SARS/COVID-19 whose data were available on the Influenza Epidemiological Surveillance Information System (SIVEP-GRIPE) platform. The primary outcome was death within 90 days (Time Event). Results: 263,884 individuals were studied, with an average age of 67.5 years and a standard deviation of ±15.2 years. It was observed that 69.3% of patients with CVD had other associated comorbidities. Among these, diabetes (49.5%) and obesity (17.9%) were the most prevalent. Additionally, 39.5% of these patients required admission to an intensive care unit (ICU) and 22.5% required some form of ventilatory support during the course of the disease. Vaccination reduced the risk of death by 24% (IRR: 0.76, 95% CI: 0.75-0.77, p<0.001). The second dose of the vaccine and the booster dose reduced the risk of death by 18% (RR: 0.82, 95% CI: 0.81-0.84, p<0.001) and 36% (RR: 0.64, 95% CI: 0.63-0.66, p<0.001), respectively. The first dose showed a smaller, but still significant, reduction in the risk of death (RR: 0.98, 95% CI: 0.96-0.99, p=0.021). Discussion: The results obtained reinforce the efficacy of vaccination against COVID-19 in reducing mortality among these patients. We observed significant differences between the vaccinated and unvaccinated groups, which became more evident from the 30th day after vaccination. Specifically, vaccination resulted in a 24% decrease in the risk of death in this population. Furthermore, the benefits of vaccination were even more evident after the administration of the second dose (18% reduction in the risk of death) and the booster dose (36% reduction in the risk of death). Conclusion: Vaccination against COVID-19 is effective in reducing mortality and the need for ventilatory support in patients with CVD. This is especially relevant, considering that these patients represent a high-risk population, with a higher likelihood of developing severe forms of the disease and adverse consequences. The importance of full adherence to the vaccination schedule, including the booster dose, is emphasized, as the benefits of vaccination become more evident after the administration of these subsequent doses.