Brazilian flu vaccine put to the test against global standard
NCT ID NCT03777163
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This completed Phase 4 trial tested whether the Butantan Institute's seasonal flu vaccine is as safe and effective as the Sanofi vaccine. A total of 632 Brazilian adults aged 18 to 69 received one of the two vaccines. Researchers measured immune response through blood tests and tracked side effects like pain, fever, and fatigue for up to 21 days after vaccination.
What this could mean
Our plain-language read of the trial. This is informational only — not medical advice or a prediction.
Active substance
Trivalent seasonal influenza vaccine (inactivated, split-virion, egg-based)
What this could lead to
If successful, this could confirm that the Butantan flu vaccine is as safe and effective as the Sanofi vaccine, offering a reliable alternative for seasonal flu prevention.
What could go wrong
This is a completed Phase 4 trial, so results are already in. However, the study only included adults in Brazil, so findings may not apply to other populations or age groups.
Disclaimer
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This is a summary of
the original study
.
Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.
This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
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Locations
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Centro de Pesquisas Clínicas do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo
São Paulo, São Paulo, 05403 000, Brazil
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Centro de Referência de Imunobiológicos Especiais (CRIE) Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo
São Paulo, São Paulo, 05403-000, Brazil
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Centro de Referências para Imunobiológicos Especiais da Universidade Federal de São Paulo
São Paulo, São Paulo, 01220200, Brazil
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Unidade de Pesquisa Clínica do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo
Ribeirão Preto, São Paulo, 14049900, Brazil