Fourth COVID shot may shield seniors from severe illness
NCT ID NCT05283902
First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This completed study in Brazil looked at whether a fourth dose of a COVID-19 vaccine helps protect people aged 60 and older from hospitalization and death. Researchers tracked 260 elderly participants who received a second booster and compared their immune responses to samples from immunosuppressed patients. The goal was to see if the extra dose lowers severe outcomes and is safe.
What this could mean
Our plain-language read of the trial. This is informational only — not medical advice or a prediction.
Active substance
COVID-19 vaccine (ChAdOx1 nCoV-19, Comirnaty, or Janssen)
What this could lead to
If successful, this could show that a fourth dose offers extra protection against severe COVID-19 in older adults, helping guide booster recommendations.
What could go wrong
This is an observational study, not a controlled trial, so results may be less definitive. The sample for immune testing is small (260 people), and findings may not apply to other regions or variants.
Disclaimer
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This is a summary of
the original study
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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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Valéria Valim
Vitória, Espírito Santo, 29041-295, Brazil