Can a pill and a vaccine stop STIs in High-Risk men?

NCT ID NCT04597424

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This study tested two strategies to prevent sexually transmitted infections (STIs) in men who have sex with men and already take HIV PrEP. One group took doxycycline pills after unprotected sex, and another group received a meningitis vaccine (Bexsero). The goal was to see if these approaches could reduce new cases of chlamydia, syphilis, and gonorrhea. Over 550 men took part in this completed Phase 3 trial.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

doxycycline and Bexsero® vaccine

What this could lead to

If it works, this could offer a new way to prevent bacterial STIs in high-risk groups, reducing infections like chlamydia, syphilis, and gonorrhea.

What could go wrong

This is a completed Phase 3 trial, but results may not apply to all populations. Doxycycline overuse could lead to antibiotic resistance, and the vaccine may not protect against all gonorrhea strains.

Disclaimer Read more

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.

Risk-Taking Unsafe Sex bacterial sexually transmitted disease prevention target HIV infectious disease prevention target meningococcal infection prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Hôpital Bichat

    Paris, 75000, France

  • Hôpital Européen Georges Pompidou

    Paris, 75908, France

  • Hôpital Hôtel Dieu

    Paris, 75181, France

  • Hôpital Necker-Enfants Malades

    Paris, 75743, France

  • Hôpital Pitié-Salpétrière

    Paris, 75651, France

  • Hôpital Saint-Antoine

    Paris, 75571, France

  • Hôpital Saint-Louis

    Paris, 75475, France

  • Hôpital Tenon

    Paris, 75970, France

  • Hôpital pitié Salpetrière

    Paris, 75651, France