- Design
- Randomised, single-blind, controlled trial
- Population
- 110 adults with HIV in Thailand (103 per protocol), median CD4 555 cells/mm3
- Primary outcome
- Seroprotection to all four strains at 1 month
- Effect
- 61.5% vs 39.2% (p=0.02); A/H3N2 76.9% vs 52.9%
This single-blind randomised trial in Thailand compared high-dose (60 micrograms per strain) with standard-dose (15 micrograms) quadrivalent inactivated influenza vaccine in 110 adults with HIV; 103 were analysed per protocol. Most were virally suppressed, and the median CD4 count was 555 cells/mm3.
Protective antibody titres to all four strains at one month were reached by 61.5% with high dose and 39.2% with standard dose. The difference was clearest for A/H3N2 (76.9% vs 52.9%). Adverse events were similar (55.8% vs 58.8%), mostly injection-site reactions.
This measures antibodies, not infections prevented. It is a reasonable basis for considering high-dose vaccine where it is available, but not proof that it prevents more influenza in people with HIV.
- Offer annual influenza vaccination to every person with HIV.
- Consider high-dose vaccine where available, particularly for older patients or those with lower CD4 counts.
- Expect similar local reactions with either dose.
- Keep antiretroviral therapy and viral suppression on track; they underpin vaccine response.
Why it matters
Standard-dose vaccine left most of this well-controlled group short of protective titres to all four strains.
Don't overread it
Higher antibody levels have not yet been shown to mean fewer influenza infections in this group.
The statistics, in plain English
The trial measured seroprotection, an antibody level associated with protection, not actual influenza cases. A per-protocol analysis includes only those who completed the study, which can overstate an effect slightly.
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