Technical Comittee's note on the COVID-19 article regarding vaccines

Dear Editor,

As an independent and interinstitutional Advisory Committee[i] nominated by the President of Fiocruz during the COVID-19, we are writing to address key issues regarding the recent article by Rodrigues and Andrade[ii], which examined post-vaccination mortality rates after hospitalization by COVID-19. Although the article does not question the importance of vaccines, it presents imprecise and biased claims regarding the efficacy and safety of vaccines after three months and one year of severe case of COVID-19.

While we appreciate the authors' effort to analyse this important public health topic, we have significant methodological concerns that warrant careful consideration. The hypothesis put forward by the paper is at odds with the overwhelming scientific knowledge published about vaccines and vaccination not only against COVID-19 but against many other vaccine-preventable diseases.

However, the published article in question suffers from inherent methodological limitations due to, among other factors, its uncontrolled observational nature based on inadequate use of the database cited, and lack of statistical significance. Additionally, it does not reference other studies from several research groups across the world, including other Brazilian studies that used the same database.

While Brazil's national health database is indeed robust and valuable, the authors' approach to data analysis presents several critical limitations: i) the database[iii], while comprehensive for its intended purposes, is not structured to test the specific hypotheses proposed by the authors regarding long-term mortality differences between vaccinated and unvaccinated populations; ii) the analysis fails to account for crucial confounding variables that could significantly impact mortality rates, vaccination and symptoms onset dates, and socioeconomic factors; iii) the authors' conclusions regarding higher mortality rates among vaccinated individuals after one year require more sophisticated statistical approaches and multiple data source integration to establish causality.

For a proper evaluation of COVID-19 vaccination impact in deaths after a case of Severe Acute Respiratory Infection (SARI) by COVID-19, researchers must combine the SIVEP-Gripe database with both the mortality and vaccination databases.

Another relevant issue we must address refers to the robust scientific consensus regarding the safety and effectiveness of vaccines. The International Vaccine Access Center (IVAC) at Johns Hopkins Bloomberg School of Public Health hosts a comprehensive database, the VIEW-hub[iv], which compiles numerous peer-reviewed studies that consistently demonstrated the safety and efficacy of several vaccines, including those for COVID-19. The findings of the papers curated collection by IVAC are based on multiple large-scale, controlled studies conducted across diverse populations and healthcare systems.

Notably, the authors also failed to reference or engage with this substantial body of evidence, including several studies that utilized the same Brazilian database they analysed[v], and to consider the broader body of evidence from the health surveillance ecosystem[vi].

This Committee corroborates the understanding and knowledge accumulated over the years, not only after vaccination against COVID-19 but other diseases as well, that there is a substantial body of scientific evidence demonstrating the significant benefits and safety of vaccines.

These limitations raise concerns about the validity of its conclusions, which could potentially exacerbate vaccine hesitancy, reminiscent of past misinformation campaigns surrounding vaccines, such as those linking the MMR vaccine to autism—a claim thoroughly debunked by extensive research.

A more recent event related to COVID-19 vaccines led to an Expression of Concern by the editorial board of the British Medical Journal[vii] regarding an article that made inappropriate and misleading conclusions about COVID-19 vaccines and mortality risk published in BMJ[viii]. This issue was also under investigation by Reuters[ix] which interviewed several renowned scholars who highlight several methodological issues. It is noteworthy that after the publication of the study in question published in Frontiers in Medicine, not only the Brazilian Ministry of Health[x], but several renowned Brazilian scientific institutions have already expressed their concerns about the study in question[xi]. 

It is crucial to maintain scientific rigour while avoiding ideological polarization in vaccine research. Papers submitted for scientific publication addressing causality related to health conditions, which are multifactorial in nature, should use multiple appropriate and robust databases to test hypotheses that are inherently multicriteria, and clearly state the paper's methodological limitations and the limitations of the inferences put forward.  

The scientific community has a responsibility to ensure that published research meets rigorous methodological standards, particularly regarding public health interventions. While the Brazilian database is a valuable resource, its appropriate use and interpretation are crucial for maintaining public trust in scientific research and vaccine programs. Based on these considerations, we recommend the following actions:

1. A call for comprehensive analysis and the publication of references that have analysed data related to millions of vaccine doses administered not only in Brazil but in other countries.
2. Publication of a clarification regarding the methodological limitations for establishing causal relationships.
3. Acknowledgement of the extensive body of evidence supporting vaccine safety and effectiveness, including studies using the same Brazilian database.
4. Recognition that conclusions regarding increased long-term mortality among vaccinated individuals require more robust methodological approaches and multiple data sources.

Thank you for considering these points as part of a constructive dialogue on this important topic.

Sincerely,

The members of the Committee, in alphabetical order below:

Akira Homma

Antonio Carlos Campos de Carvalho

Beatriz de Castro Fialho

Cristiana Toscano

Gerson Oliveira Penna

Marco Aurelio Krieger

Marilda Siqueira

Mario Santos Moreira;

Moises Goldbaum

Wilson Savino

[i] The Technical-Scientific Monitoring Committee for Initiatives Related to COVID-19 Vaccines was established in 2020 to provide scientific guidance for decision-making by the Fiocruz Presidency regarding actions related to COVID-19 vaccines. The Committee is composed of renowned researchers with extensive experience in conducting scientific studies

[ii] Rodrigues, N.C.P. and Andrade, M.K.N., Evaluation of post-COVID mortality risk in cases classified as severe acute respiratory syndrome in Brazil: a longitudinal study for medium and long term, Frontiers in Medicine, 11, 2024. https://doi.org/10.3389/fmed.2024.1495428

[iii] The Influenza Epidemiological Surveillance Information System (SIVEP-Gripe) is an administrative database created by the Ministry of Health for the epidemiological surveillance of Severe Acute Respiratory Infections (SARI) in Brazil

[iv] https://view-hub.org/vaccine/covid

[v] https://www.nature.com/articles/s41467-022-32524-5; https://pubmed.ncbi.nlm.nih.gov/35952702/; https://www.nature.com/articles/s41591-022-01701-w ; https://www.nature.com/articles/s41467-022-32524-5 ; https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-023-16196-4; https://www.sciencedirect.com/science/article/pii/S1201971224003126; https://www.nature.com/articles/s41467-022-33169-0; among others.

[vi] See: https://www.aen.pr.gov.br/Noticia/Risco-de-obito-por-Covid-19-e-22-vezes-menor-entre-vacinados-com-dose-de-reforco-aponta#:~:text=Em%20pacientes%20idosos%2C%20os%20dados,com%20a%20dose%20de%20refor%C3%A7o; https://saude.rs.gov.br/estudo-demonstra-reducao-de-ate-16-vezes-no-risco-de-morte-por-covid-19-em-pessoas-com-segundo-reforco; https://www.saude.sp.gov.br/ses/perfil/cidadao/homepage/destaques/covid-19-mata-26-vezes-mais-os-nao-vacinados-em-sp

https://agenciabrasil.ebc.com.br/radioagencia-nacional/saude/audio/2022-01/no-rio-mortes-por-covid-em-nao-vacinados-foi-tres-vezes-maior; https://agenciabrasil.ebc.com.br/saude/noticia/2022-01/com-vacinacao-rj-teve-queda-de-91-nas-mortes-por-covid-19; https://sbim.org.br/covid-19;

[vii] Expression of concern: Excess mortality across countries in the western world since the COVID-19 pandemic: ‘Our World in Data’ estimates of January 2020 to December 2022: BMJ Public Health 2024;2, June 13th 2024. https://bmjpublichealth.bmj.com/content/2/1/e000282eoc

[viii] Saskia Mostert, Marcel Hoogland, Minke Huibers, Gertjan Kaspers - Excess mortality across countries in the Western World since the COVID-19 pandemic: ‘Our World in Data’ estimates of January 2020 to December 2022. https://bmjpublichealth.bmj.com/content/2/1/e000282

[ix]Fact Check: Study does not say COVID vaccines may have fuelled excess deaths. https://www.reuters.com/fact-check/study-does-not-say-covid-vaccines-may...

[x] https://agenciagov.ebc.com.br/noticias/202501/ministerio-saude-contesta-...

[xi] https://ufrj.br/2025/01/nota-sobre-as-vacinas-como-forma-de-prevencao-da-covid-19/; https://www.ims.uerj.br/blog/2025/01/08/nota-publica/;