Opioid use may weaken flu shots in HIV patients, study suggests
NCT ID NCT04304768
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study looks at how opioid use affects the immune system's response to the flu vaccine in people with and without HIV. Researchers will analyze blood samples from 400 participants to measure antibody levels and immune cell activity. The goal is to understand why opioid users may have weaker immune defenses 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
- Fluzone Quadrivalent (influenza vaccine)
- What this could lead to
- If successful, this could reveal how opioids impair vaccine effectiveness in people with HIV, guiding better vaccination strategies.
- What could go wrong
- This is an observational study focused on immune markers, not a treatment trial. Results may not lead to direct clinical changes.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
-
About 400 people
The number the study aims to enrol. It can still change while the study runs.
- Started
-
Nov 2020
- Expected to finish
-
Dec 2027
An estimate. End dates often move.
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
18 to 60 years
- Sex
-
Anyone
- Healthy volunteers
-
Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: For Opioid (OP) users/non-users: 1. OP users - prescribed opioids for at least the past 90 days; or injecting opioids for at least 90 days 2. Opioid never-users in the past year Additional criteria for OP users: 1. OP use for 90 days pre-flu vaccination 2. Continued OP use for 4 weeks post flu vaccination For HIV positive participants: 1\) HIV infection, as documented by any licensed ELISA kit and confirmed by Western blot at any time prior to study entry. Participants on ART as a result of prior HIV documented infection will not be required to provide proof of diagnosis of HIV infection. Additional criteria for HIV positive participants: 1. On ART for at least 1 year with plasma pending viral load (VL) \<200 copies/mL. Occasional viral blips up to 1000 copies/ml also acceptable provided the patients are on continuing treatment 2. CD4 count available in the prior 6 months and \>200/mm3 3. Undetectable viral load (\< 200 copies/mL) For HIV negative participants: 1\) Documented negative HIV test, either by any licensed ELISA or rapid tests within the past 6 months. For all participants: 1. Individuals age 18-60 yrs . 2. No history of other immunodeficiency disorders 3. Not on steroid or other immunosuppressive/immunomodulators medications. 4. No active malignancies. 5. No contraindication to receive influenza vaccination (allergy to chicken eggs or to any other substance of the vaccine). 6. Agreeable to receive the influenza vaccination. 7. Agreeable to participate in study for a complete course of study full visits. 8. Able to provide informed consent. Exclusion Criteria: 1. Contraindication to receive influenza vaccination (allergy to chicken eggs or to any other substance of the vaccine). 2. Non-adherence to ART for HIV+ 3. Unable to provide informed consent. 4. Other comorbid conditions such as diabetes mellitus type 2 (DMT2) 5. Influenza vaccination already given during the current vaccination season.
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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
Locations
-
University of Miami
Miami, Florida, 33136, United States
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Other studies related to the condition(s) this trial covers.
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