Background:
Differential transmission from HIV-infected compared to HIV-uninfected individuals may impact influenza burden. We estimated the household secondary infection risk (SIR) and serial interval (SI) for influenza transmission from HIV-infected and HIV-uninfected index cases and identified associated factors.
Methods:
Index cases were the first symptomatic person in a household with influenza-like illness, testing influenza positive on real-time reverse transcription polymerase chain reaction (rRT-PCR). Nasopharyngeal swabs collected from household contacts every four days were tested by rRT-PCR. Factors associated with SIR were evaluated using logistic regression.
Results:
We enrolled 28 HIV-infected and 57 HIV-uninfected index cases. On multivariable analysis, HIV-infected index cases were less likely to transmit influenza to household contacts (odds ratio (OR) 0.2 95% CI 0.1-0.6)(SIR 16%, 18/113 vs 27%, 59/220). Factors associated with increased SIR included index age group 1-4 years (OR 3.6, 95% CI 1.2-11.3) and 25-44 years (OR 8.0, 95% CI 1.8-36.7) and contact age group 1-4 years (OR 3.5, 95%CI 1.2-10.3) compared to 5-14 years and sleeping with index case (OR 2.7, 95%CI 1.3-5.5). HIV-infection of index case was not associated with SI.
Conclusions:
HIV-infection was not associated with SI. Increased infectiousness of HIV-infected individuals is likely not an important driver of community influenza transmission.