Effects [FET1] of Influenza Vaccination of Health Care Workers on Mortality of Elderly People in Long-Term Care: A Randomized Controlled Trial

CLINICAL QUESTION: Does vaccination of health care providers working in long-term care facilities lower mortality and rates of influenza infection in patients?

BACKGROUND: The Centers for Disease Control and Prevention (CDC) recommend influenza vaccination of all patients in long-term care facilities and of health care workers employed there. Several studies have demonstrated the effectiveness of vaccinating elderly patients, and other studies have shown decreased infection rates in vaccinated health care workers.^1,2 The effectiveness of vaccinating health care workers for preventing the spread of infection from worker to patient is not as well documented. The authors of this study evaluated whether vaccinating the health care workers at long-term care facilities reduced the nosocomial infection rate and the mortality of the patients in the facilities.

POPULATION STUDIED: A total of 1217 health care workers from 20 long-term care geriatric facilities in Scotland and the 1437 patients for whom they cared during a 6-month period participated in the study. Patients’ age, sex, and degree of disability based on a modified Barthel index were recorded.

STUDY DESIGN AND VALIDITY: Long-term care facilities were matched according to the number of beds and the vaccination policy. Employees randomly selected from half of these facilities were offered an influenza vaccination. Approximately half of the health care workers who were offered a vaccination received it, compared with less than 5% of workers in the control group. A random sample of 50% of the patients at each facility underwent prospective influenza monitoring by nasal and throat swab. Because patient demographics were not well defined, it is difficult to determine if the patients and long-term care facilities in the study are similar to those in other countries. Vaccinations are not routine for the elderly population of the United Kingdom. Consequently, vaccinating a transmission source such as health care workers could be more beneficial in the United Kingdom than in the United States. Also, all-cause mortality rates were very high (13.6%-22.4%) during the 6 months of the study, denoting a higher-risk population than that encountered in many other facilities.

OUTCOMES MEASURED: The outcomes measured included the mortality rate of patients during the winter months and the number of confirmed cases of influenza A and B.

RESULTS: Influenza rates were similar (5.4% vs 6.7%). Overall, the vaccination program was associated with lower mortality (13.6% vs 22.4%, P=.014) among residents. This benefit remained even after adjusting for the higher vaccination rate of residents in the facilities in which the health care workers were not vaccinated. However, after accounting for differences in age, sex, vaccination rate, and disability between the 2 groups, the reduction in the adjusted mortality rate was not statistically significant (adjusted odds ratio=0.6; 95% confidence interval, 0.36-1.04; P=.09).

CLINICAL QUESTION: Does vaccination of health care providers working in long-term care facilities lower mortality and rates of influenza infection in patients?

BACKGROUND: The Centers for Disease Control and Prevention (CDC) recommend influenza vaccination of all patients in long-term care facilities and of health care workers employed there. Several studies have demonstrated the effectiveness of vaccinating elderly patients, and other studies have shown decreased infection rates in vaccinated health care workers.^1,2 The effectiveness of vaccinating health care workers for preventing the spread of infection from worker to patient is not as well documented. The authors of this study evaluated whether vaccinating the health care workers at long-term care facilities reduced the nosocomial infection rate and the mortality of the patients in the facilities.

POPULATION STUDIED: A total of 1217 health care workers from 20 long-term care geriatric facilities in Scotland and the 1437 patients for whom they cared during a 6-month period participated in the study. Patients’ age, sex, and degree of disability based on a modified Barthel index were recorded.

STUDY DESIGN AND VALIDITY: Long-term care facilities were matched according to the number of beds and the vaccination policy. Employees randomly selected from half of these facilities were offered an influenza vaccination. Approximately half of the health care workers who were offered a vaccination received it, compared with less than 5% of workers in the control group. A random sample of 50% of the patients at each facility underwent prospective influenza monitoring by nasal and throat swab. Because patient demographics were not well defined, it is difficult to determine if the patients and long-term care facilities in the study are similar to those in other countries. Vaccinations are not routine for the elderly population of the United Kingdom. Consequently, vaccinating a transmission source such as health care workers could be more beneficial in the United Kingdom than in the United States. Also, all-cause mortality rates were very high (13.6%-22.4%) during the 6 months of the study, denoting a higher-risk population than that encountered in many other facilities.

OUTCOMES MEASURED: The outcomes measured included the mortality rate of patients during the winter months and the number of confirmed cases of influenza A and B.

RESULTS: Influenza rates were similar (5.4% vs 6.7%). Overall, the vaccination program was associated with lower mortality (13.6% vs 22.4%, P=.014) among residents. This benefit remained even after adjusting for the higher vaccination rate of residents in the facilities in which the health care workers were not vaccinated. However, after accounting for differences in age, sex, vaccination rate, and disability between the 2 groups, the reduction in the adjusted mortality rate was not statistically significant (adjusted odds ratio=0.6; 95% confidence interval, 0.36-1.04; P=.09).

CLINICAL QUESTION: Does vaccination of health care providers working in long-term care facilities lower mortality and rates of influenza infection in patients?

BACKGROUND: The Centers for Disease Control and Prevention (CDC) recommend influenza vaccination of all patients in long-term care facilities and of health care workers employed there. Several studies have demonstrated the effectiveness of vaccinating elderly patients, and other studies have shown decreased infection rates in vaccinated health care workers.^1,2 The effectiveness of vaccinating health care workers for preventing the spread of infection from worker to patient is not as well documented. The authors of this study evaluated whether vaccinating the health care workers at long-term care facilities reduced the nosocomial infection rate and the mortality of the patients in the facilities.

POPULATION STUDIED: A total of 1217 health care workers from 20 long-term care geriatric facilities in Scotland and the 1437 patients for whom they cared during a 6-month period participated in the study. Patients’ age, sex, and degree of disability based on a modified Barthel index were recorded.

STUDY DESIGN AND VALIDITY: Long-term care facilities were matched according to the number of beds and the vaccination policy. Employees randomly selected from half of these facilities were offered an influenza vaccination. Approximately half of the health care workers who were offered a vaccination received it, compared with less than 5% of workers in the control group. A random sample of 50% of the patients at each facility underwent prospective influenza monitoring by nasal and throat swab. Because patient demographics were not well defined, it is difficult to determine if the patients and long-term care facilities in the study are similar to those in other countries. Vaccinations are not routine for the elderly population of the United Kingdom. Consequently, vaccinating a transmission source such as health care workers could be more beneficial in the United Kingdom than in the United States. Also, all-cause mortality rates were very high (13.6%-22.4%) during the 6 months of the study, denoting a higher-risk population than that encountered in many other facilities.

OUTCOMES MEASURED: The outcomes measured included the mortality rate of patients during the winter months and the number of confirmed cases of influenza A and B.

RESULTS: Influenza rates were similar (5.4% vs 6.7%). Overall, the vaccination program was associated with lower mortality (13.6% vs 22.4%, P=.014) among residents. This benefit remained even after adjusting for the higher vaccination rate of residents in the facilities in which the health care workers were not vaccinated. However, after accounting for differences in age, sex, vaccination rate, and disability between the 2 groups, the reduction in the adjusted mortality rate was not statistically significant (adjusted odds ratio=0.6; 95% confidence interval, 0.36-1.04; P=.09).