Predictors of seasonal influenza vaccination among older adults in Thailand

Abstract

BackgroundIn advance of a large influenza vaccine effectiveness (VE) cohort study among older adults in Thailand, we conducted a population-based, cross-sectional survey to measure vaccine coverage and identify factors associated with influenza vaccination among older Thai adults that could bias measures of vaccine effectiveness.MethodWe selected adults ≥65 years using a two-stage, stratified, cluster sampling design. Functional status was assessed using the 10-point Vulnerable Elders Survey (VES); scores ≥3 indicated vulnerability. Questions about attitudes towards vaccination were based on the Health Belief Model. The distance between participants’ households and the nearest vaccination clinic was calculated. Vaccination status was determined using national influenza vaccination registry. Prevalence ratios (PR) and 95% confidence intervals (CIs) were calculated using log-binomial multivariable models accounting for the sampling design.ResultWe enrolled 581 participants, of whom 60% were female, median age was 72 years, 41% had at least one chronic underlying illness, 24% met the criteria for vulnerable, and 23% did not leave the house on a daily basis. Influenza vaccination rate was 34%. In multivariable models, no variable related to functional status was associated with vaccination. The strongest predictors of vaccination were distance to the nearest vaccination center (PR 3.0, 95% CI 1.7–5.1 for participants in the closest quartile compared to the furthest), and high levels of a perception of benefits of influenza vaccination (PR 2.8, 95% CI 1.4–5.6) and cues to action (PR 2.7, 95% CI 1.5–5.1).ConclusionDistance to vaccination clinics should be considered in analyses of influenza VE studies in Thailand. Strategies that emphasize benefits of vaccination and encourage physicians to recommend annual influenza vaccination could improve influenza vaccine uptake among older Thai adults. Outreach to more distant and less mobile older adults may also be required to improve influenza vaccination coverage.

Seasonal influenza vaccination in older people: A systematic review and meta-analysis of the determining factors

“…Where appropriate, we pooled data using the inverse variance, random-effects model implemented in STATA (version 13; StataCorp LP, Texas, USA) and reported the pooled adjusted odds ratios (OR) and their 95% confidence intervals (CI). Adjusted relative risks, as well as adjusted rate and prevalence ratios (reported by only 3 studies) [22][23][24], were pooled with adjusted ORs. Statistical heterogeneity between pooled results was assessed and quantified using the I-squared statistic (I 2 ).…”

Factors influencing the uptake of influenza vaccine vary among different groups in the hard‐to‐reach population

“…Traditionally, outreach vaccination programs have been used in low‐ and middle‐income countries. Some communities in these countries frequently have difficulty accessing vaccines due to geographical barriers to healthcare facilities 25–27 . Since early 2000, the World Health Organization advocated using the ‘Reaching Every District’ (RED) strategy to reach out to under‐served, un‐reached communities 28 .…”

“…Some communities in these countries frequently have difficulty accessing vaccines due to geographical barriers to healthcare facilities. [25][26][27] Since early 2000, the World Health Organization advocated using the 'Reaching Every District' (RED) strategy to reach out to under-served, un-reached communities. 28 This has been successfully rolled out in certain countries.…”

Effect of acute respiratory illness on short‐term frailty status of older adults in Nakhon Phanom, Thailand—June 2015 to June 2016: A prospective matched cohort study

“…Functional disability was assessed based on self‐reported ability to perform specific activities (shop, manage money, walk across room, do light housework, and bathe) where if the person answered yes to having difficulty doing a specific activity, needed help to complete the activity, or did not do the activity because of their health, they were considered to have a disability and assigned a score of 4 and if no disability was identified, they were assigned a score of 0. The health status rating options were modified from the original VES‐13 to allow comparability to previous studies in this population . The scores for the three components were summed and could range from 0 to 7 points.…”

“…The health status rating options were modified from the original VES-13 to allow comparability to previous studies in this population. 18 The scores for the three components were summed and could range from 0 to 7 points. Higher scores are associated with frailty and an increased risk of death or functional decline.…”