Comparison of influenza vaccination rates between general older adults and elders with intellectual disability

Objective: Vaccination is one of the most effective strategies in preventing seasonal influenza, especially for the immune-compromised older adults. However, few studies have investigated the difference in vaccination against seasonal influenza among these vulnerable populations. In this study, we used the National Health Insurance (NHI) claims data to examine the vaccination rates between the older adults and elders with intellectual disability (ID) in Taiwan.

Methods: Using one-million-random sample of the NHI claim data in 2007, enrollees of NHI aged 65 and over with ICD codes of intellectual Disabilities were identified and propensity score matching method was used to form the comparison sample. Multivariate logistic models were used to compare the rates of vaccination against seasonal influenza.

Results: Results showed that, in 2007, the overall vaccination rate for people aged 65 or over was 33.2% and 36.9% for older people with ID. Compared to the general older adults, enrollees with ID were 1.15 times (95% CI=1.04, 1.27) more likely to be vaccinated. For the institutionalized older people with ID, their chance of being vaccinated was even higher (OR=2.66, 95% CI=1.82, 3.90).

Conclusions: It's normally expected that people from a disadvantaged group would use less needed preventive services. However, our findings suggest that the opposite is true. Plausible explanations are directed to the differences in the time/opportunity costs between community-dwelling older people and people with ID.