Vaccine history, gender and influenza vaccination in a household context

Background: Few studies have investigated the effect of the history of vaccination on the current influenza vaccine uptake. The objective of this paper is to study the effects of vaccine history, for each sex separately, on the likelihood of vaccine uptake among single-head households and two-person households, controlling not only for the respondents' own prior vaccination history but also the history of vaccination among possible co-residents.

Materials and methods: We used logistic regression and data from a nationally representative telephone survey of the non-institutionalized Norwegian population aged ≥ 65 years to estimate our models (N=354). The survey was carried out in November 2008.

Results: The lowest vaccine uptake was found among those who live alone with no prior history of vaccination and among those who live in two-person households where both members had no prior history of vaccination (10-22%). Those who live in two-person households where both members had previously been vaccinated had the highest vaccine uptake (86%). While a man who has previously been vaccinated has a higher likelihood of continued vaccination if his wife also has a prior history of vaccination, a woman with a prior history of vaccination is not dependent on her husband's prior practice with respect to the probability of continued vaccination. Of those who have no history of vaccination, more women than men are vaccinated for the first time when they have a spouse who has a history of vaccination.

Conclusion: Our study shows that the history of vaccination of a co-resident/spouse has an effect above and beyond the respondent's own vaccination history. The results indicate that there are gender differences in the willingness to encourage family members to be vaccinated or to embark upon a familial vaccination regime in order to protect the individual's own personal health and that of other family members from influenza. To the best of our knowledge such gender differences have never been shown before in research on influenza vaccine uptake. However, the finding is in accordance with a number of studies on the role of gender and the positive effect on health and mortality of social support and social control in marriage.