A recent longitudinal study by Nádia Cristina Pinheiro Rodrigues and Mônica Kramer de Noronha Andrade, both from Rio de Janeiro, sheds light on mortality after COVID infection in Brazil between 2020 and 2023, focusing on cases of severe acute respiratory syndrome (SARS). . Rodrigues works at the Escola Nacional de Saúde Pública Sérgio Arouca/Fundação Oswaldo Cruz and the Universidade do Estado do Rio de Janeiro, while Andrade conducts research at the Universidade Federal do Rio de Janeiro. The study, funded by the Fundação Oswaldo Cruz (FIOCRUZ), examines the medium- and long-term risks of mortality after COVID vaccination, taking into account demographic, clinical, and vaccine-specific factors. While vaccination is associated with a lower risk of death in the short term, the vaccinated cohort showed an almost double risk of mortality in the long term.
Study objectives
The researchers hypothesized that demographic factors, comorbidities, and vaccination status could influence the risk of death after COVID vaccination. The aim of the study was to assess the interactions of these variables over time, focusing on the medium-term protective effect of vaccination (3-12 months) and potential long-term risks (over one year).
Study design and methods
This retrospective cohort study analyzed SARS cases classified as COVID-19 based on the Brazilian national database Sistema de Vigilância Epidemiológica (SIVEP). The cohort included 15,147 people, including 5,157 deaths. Medium-term (3-12 months after symptom onset) and long-term mortality (over one year) were assessed separately. The analysis was performed using classic Cox, mixed-effects, and fragile Cox models. Vaccination status, number of doses, demographic factors, comorbidities, and regional disparities were used as predictors.
Key findings
In the medium term, vaccination was shown to reduce the risk of death by 4–8%, with greater reductions (11–18%) observed with two or three doses of the vaccine. Risk factors such as age, male gender, low education, and comorbidities (e.g., diabetes, heart disease) were significant. Regional differences revealed a higher risk of death in the north of Brazil compared to the southeast and northeast.
Long-term mortality
In the long term, the risk of death increased among vaccinated people, especially those with one or two doses of the vaccine, where the risk almost doubled. In addition to advanced age and comorbidities, liver disease was found to be a significant risk factor. Survival was better in the Midwest and Southeast regions, likely due to socioeconomic and health disparities.
Limitations and biases
The study is subject to potential biases, such as selection bias, as only severe SARS cases were examined. This means that milder cases of COVID-19 are not taken into account. Data gaps – such as the exact type of vaccine, the time of administration and the causes of death – as well as the lack of access to vaccine adverse event reporting systems made the analysis even more difficult. Geographic and socioeconomic differences could further confound mortality trends.
Assumptions and potential issues
The study is based on the assumption that vaccination status and vaccine dose were recorded uniformly and that survival curves accurately reflect mortality risks. However, aspects such as access to healthcare, post-COVID syndromes or progression of chronic diseases were not taken into account.
Funding and acknowledgements
The study was funded by the FIOCRUZ Graduate Program in Public Health. Luiz Antônio Camacho provided methodological support and FIOCRUZ contributed to the publication. The authors declare no conflicts of interest.
Conclusion
The study highlights the complex dynamics of mortality after COVID infection. It shows a medium-term protective effect of vaccination, but also an unexpectedly increased risk of death in the long term. Regional and demographic differences highlight the need for targeted public health interventions. Further research is needed to understand the underlying biological and social mechanisms, especially regarding the long-term risks of vaccination. The results highlight the importance of continuous monitoring and improved data transparency.
Research leader:
Nádia Cristina Pinheiro Rodrigues – Escola Nacional de Saúde Pública Sérgio Arouca/Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
Mônica Kramer de Noronha Andrade – Universidade Federal do Rio de Janeiro, Brazil
Source: https://www.trialsitenews.com/a/investigating-post-covid-mortality-in-brazillong-term-mortality-risk-nearly-doubles-for-vaccinated-persons-002c9f42
