Flu: Effect of Vaccine in Elderly Care Home Residents: A Randomized Trial
Flu: Effect of Vaccine in Elderly Care Home Residents: A Randomized Trial
Objectives: To determine whether assessing seroprotection after influenza vaccine and administering booster vaccination where not achieved reduces hospitalization and death. To estimate the overall seroprotection rate of influenza vaccine.
Design: A two-arm, partially blind, randomized, multicenter, parallel-group, controlled trial.
Setting: Twenty-six care homes in three South London boroughs in fall 2004.
Participants: Two hundred seventy-seven elderly permanent care home residents meeting eligibility criteria.
Intervention: Postvaccination blood samples were randomized to booster evaluation or no booster evaluation (control). If evaluation revealed inadequate seroprotection, a booster vaccine was administered.
Measurements: Primary outcome was hospitalization to end April 2005; secondary outcomes were death, antibiotic use, and seroprotection.
Results: Sixty percent of the controls and 41% of the booster evaluation group responded to routine vaccination. Booster vaccination where indicated increased seroprotection rates in the booster evaluation group to 66%. Treatment groups did not differ in any outcome measures in the intention-to-treat analysis (hospitalization odds ratio=1.02, 95% confidence interval=0.55-1.87). There was a tendency towards greater differences between groups in the per-protocol analysis than in the intention-to-treat analysis, particularly regarding seroprotection rates. The same effect was observed in the a priori exploratory analysis of residents not seroprotected after routine vaccination alone.
Conclusion: In a year without circulating influenza, there is no clinical benefit of administering a booster vaccine if routine trivalent vaccination fails to result in seroprotection. Hemagglutination titers rose in two strains postbooster vaccination but fell against the novel strain, Wyoming. The benefit of such a booster strategy when influenza is prevalent thus remains unc ertain.
Influenza, an infectious disease with worldwide consequences, is a major cause of morbidity and mortality in at-risk groups, including elderly people and those in institutional care. Vaccination remains the primary defense against influenza and reduces associated mortality, hospitalization, and complications. A meta-analysis of clinical studies in elderly people found pooled odds ratios of more than 1.5 of the vaccine for preventing respiratory illness, pneumonia, hospitalization, and death. The World Health Organization estimates that vaccination of elderly people reduces the risk of serious complications or death by 70% to 85%, although a recent review criticized the body of published work as being inadequate to prove the effectiveness and safety of influenza vaccines and questioned the validity of the public health decisions made based on the work thus far.
Nevertheless, because of the threat of rapid viral spread through nursing homes, older people in UK residential care settings have been targeted for annual influenza vaccination campaigns for many years. During this time, the proportion of individuals with major psychiatric disorders in nursing or residential care has steadily risen, to the point where at least two in three is currently affected. Individuals with psychiatric diseases have weaker antibody response to inactivated vaccines, including those for hepatitis B and pertussis. Chronic stress also impairs antibody response to influenza vaccination, although no effect specific to depression has been found.
A pilot study of hemagglutination (HI) antibody response to influenza vaccination in 74 elderly residents (mean age 80) with a range of significant psychiatric illnesses was conducted in advance of the randomized, controlled trial. Only five (6.8%) patients responded to all three components of the subunit vaccine, and 26 (35.1%) failed to respond to even one component.
Elderly people should consistently achieve a fourfold increase in HI antibody response in 30% of vaccines, or 60% should have HI antibody titers greater than 40, as required for annual licensing of influenza vaccine.
Two-dose schedules have been recommended for patients in high-risk categories, because up to one-quarter of elderly residents seroconvert after a second dose of vaccine. Booster doses of influenza vaccine in frail elderly nursing home residents produced a rise in mean antibody titers of approximately 14%. In contrast, booster vaccination yielded no such effect in healthy older adults. Exploration of new vaccination strategies aiming to maximize response, serologically and clinically, in the ever-increasing care home population is therefore urgently required.
The objective of the Flu -- Effect of Vaccine in Elderly Residents Trial was to determine whether assessing seroprotection against the influenza vaccine, and administering a booster vaccination when seroprotection was not achieved, is more effective in reducing hospitalization and death rates than current standard practice. A secondary objective was to estimate the overall seroprotection rate of the influenza vaccine in the trial population.
Objectives: To determine whether assessing seroprotection after influenza vaccine and administering booster vaccination where not achieved reduces hospitalization and death. To estimate the overall seroprotection rate of influenza vaccine.
Design: A two-arm, partially blind, randomized, multicenter, parallel-group, controlled trial.
Setting: Twenty-six care homes in three South London boroughs in fall 2004.
Participants: Two hundred seventy-seven elderly permanent care home residents meeting eligibility criteria.
Intervention: Postvaccination blood samples were randomized to booster evaluation or no booster evaluation (control). If evaluation revealed inadequate seroprotection, a booster vaccine was administered.
Measurements: Primary outcome was hospitalization to end April 2005; secondary outcomes were death, antibiotic use, and seroprotection.
Results: Sixty percent of the controls and 41% of the booster evaluation group responded to routine vaccination. Booster vaccination where indicated increased seroprotection rates in the booster evaluation group to 66%. Treatment groups did not differ in any outcome measures in the intention-to-treat analysis (hospitalization odds ratio=1.02, 95% confidence interval=0.55-1.87). There was a tendency towards greater differences between groups in the per-protocol analysis than in the intention-to-treat analysis, particularly regarding seroprotection rates. The same effect was observed in the a priori exploratory analysis of residents not seroprotected after routine vaccination alone.
Conclusion: In a year without circulating influenza, there is no clinical benefit of administering a booster vaccine if routine trivalent vaccination fails to result in seroprotection. Hemagglutination titers rose in two strains postbooster vaccination but fell against the novel strain, Wyoming. The benefit of such a booster strategy when influenza is prevalent thus remains unc ertain.
Influenza, an infectious disease with worldwide consequences, is a major cause of morbidity and mortality in at-risk groups, including elderly people and those in institutional care. Vaccination remains the primary defense against influenza and reduces associated mortality, hospitalization, and complications. A meta-analysis of clinical studies in elderly people found pooled odds ratios of more than 1.5 of the vaccine for preventing respiratory illness, pneumonia, hospitalization, and death. The World Health Organization estimates that vaccination of elderly people reduces the risk of serious complications or death by 70% to 85%, although a recent review criticized the body of published work as being inadequate to prove the effectiveness and safety of influenza vaccines and questioned the validity of the public health decisions made based on the work thus far.
Nevertheless, because of the threat of rapid viral spread through nursing homes, older people in UK residential care settings have been targeted for annual influenza vaccination campaigns for many years. During this time, the proportion of individuals with major psychiatric disorders in nursing or residential care has steadily risen, to the point where at least two in three is currently affected. Individuals with psychiatric diseases have weaker antibody response to inactivated vaccines, including those for hepatitis B and pertussis. Chronic stress also impairs antibody response to influenza vaccination, although no effect specific to depression has been found.
A pilot study of hemagglutination (HI) antibody response to influenza vaccination in 74 elderly residents (mean age 80) with a range of significant psychiatric illnesses was conducted in advance of the randomized, controlled trial. Only five (6.8%) patients responded to all three components of the subunit vaccine, and 26 (35.1%) failed to respond to even one component.
Elderly people should consistently achieve a fourfold increase in HI antibody response in 30% of vaccines, or 60% should have HI antibody titers greater than 40, as required for annual licensing of influenza vaccine.
Two-dose schedules have been recommended for patients in high-risk categories, because up to one-quarter of elderly residents seroconvert after a second dose of vaccine. Booster doses of influenza vaccine in frail elderly nursing home residents produced a rise in mean antibody titers of approximately 14%. In contrast, booster vaccination yielded no such effect in healthy older adults. Exploration of new vaccination strategies aiming to maximize response, serologically and clinically, in the ever-increasing care home population is therefore urgently required.
The objective of the Flu -- Effect of Vaccine in Elderly Residents Trial was to determine whether assessing seroprotection against the influenza vaccine, and administering a booster vaccination when seroprotection was not achieved, is more effective in reducing hospitalization and death rates than current standard practice. A secondary objective was to estimate the overall seroprotection rate of the influenza vaccine in the trial population.