How complete is influenza immunization coverage? A study in 75 nursing and residential homes for elderly people

Elderly people in residential accommodation are particularly susceptible to outbreaks of influenza. Up to 70% of residents can become ill and many will develop complications or die. Immunization can prevent such outbreaks and is cost-effective.

A study was undertaken to measure influenza immunization coverage in residential accommodation for elderly people and to identify factors that might influence uptake.

In March 1992, a questionnaire survey was conducted of all 113 registered nursing and residential homes for elderly people, in South Glamorgan. It asked about the demographic characteristics of people resident on 1 October 1991, their influenza immunization history and the homes' arrangements for administering immunizations.

Questionnaires were returned by respondents from 75 homes (66%). Mean influenza vaccine uptake was 67%. Uptake was higher in nursing homes (mean of 82% in eight nursing homes) than in homes registered as both nursing and residential homes (mean of 76% in six homes) or in residential homes (mean of 65% in 61 homes). Nearly all of those immunized (94%) had been immunized by the end of November 1991. Residents who were reported to have underlying disease that increased their risk of complications if they contracted influenza were no more likely to have been immunized than those without risk factors. Immunization coverage varied considerably both between homes and between general practices. Most general practices in South Glamorgan had several elderly people in residential accommodation on their list, but only nine out of 64 practices had immunized all the elderly residents on their list and 12 practices had immunized fewer than half. Routine recording of immunization status in nursing and residential homes was variable, often as a consequence of poor communication between the primary health care team and staff at the home. Even where recorded, retrieval of the data was sometimes a problem.

Influenza immunization coverage could be improved if general practices held a case register of all at-risk patients including elderly residents, and if nursing and residential homes were encouraged to keep better immunization records. These measures would facilitate year-on-year monitoring of influenza immunization coverage and the targeting of homes with low immunization coverage.