Improving older adults' vaccination uptake: are existing measures of vaccine hesitancy valid and reliable for older people?

Older adults are particularly vulnerable to vaccine-preventable diseases (VDU), due to decreased immunity and increased comorbidity. Vaccination can support healthy ageing and help reduce morbidity, mortality, and loss of quality of life associated with VPDs. Despite the availability of effective vaccines, many countries, including the UK, fail to reach recommended coverage levels. Psychosocial factors are recognised as providing important insights into the determinants of vaccination uptake. Little research has sought to establish psychometrically sound scales of vaccine attitudes with older adults. In the present study, a total of 372 UK-based participants (65-92 years, M = 70.5 yrs, SD = 4.6) completed a cross-sectional, online survey measuring health and socio-demographic characteristics in relation to vaccination uptake for influenza, pneumococcal and shingles. Two recently developed vaccination attitude scales, the 5C scale and the Vaccination Attitudes Examination (VAX) scale, were also administered to test their reliability and validity for use with an older adult population. Additional scales used to examine convergent and discriminant validity, the Beliefs about Medicines Questionnaire, the Perceived Sensitivity to Medicines Scale, the Medical Mistrust Index, the Perceived Stress Scale, and the Interpersonal Support Evaluation List, were included. The factor structure of the 5C and VAX scales was confirmed. Both scales showed good internal reliability, convergent, discriminant and concurrent validity, supporting their use with older adult populations. The 5C and VAX scales were found to be reliable and valid psychosocial measures of vaccine hesitancy and acceptance within a UK-based, older adult population. Future research could use these scales to evaluate the impact of psychological antecedents of vaccine uptake, and how concerns about vaccination may be understood and addressed among older adults.