FROM ANNALS OF INTERNAL MEDICINE
Live attenuated influenza vaccine (LAIV) was no more effective than inactivated influenza vaccine (IIV) in small, compact, rural communities, according to Mark Loeb, MD, and his associates.
For the study, vaccinations were given to children aged 36 months to 15 years living in Hutterite colonies in Canada. Hutterite colonies are isolated, their residents live communally, and influenza is prevalent, making them suited for this cluster randomized trial.
Of the 1,186 children included in the study, mean coverage was 76.7% in the LAIV group, compared with 72.4% in the IIV group. Incidence of influenza was 5.3% in the LAIV group and 5.2% in the IIV group. Compared to IIV, the hazard ratio for LAIV for influenza A or B was 1.03.
Children vaccinated with LAIV were at a higher risk for influenza A (hazard ratio, 1.62), but were at lower risk for influenza B (HR, 0.66). Influenza attack rates were similar in children younger and older than 6 years old. Adverse reactions were more likely in the IIV group than in the LAIV group, but no serious adverse events were reported.
“Although influenza transmission networks in Hutterite communities may differ from that in other communities, there are no data to confirm this. In fact, there may be more variability in social networks between urban and rural communities – or even among various urban communities – than between Hutterite and other (rural) communities. Even if variability exists, if a clear benefit of LAIV over IIV in reducing influenza-associated illness cannot be detected in this setting it is unlikely to be seen in other communities,” the investigators noted.
Find the full study in Annals of Internal Medicine (doi: 10.7326/M16-0513).