Treatment of an influenza A outbreak in a teaching nursing home. Effectiveness of a protocol for prevention and control

The safety and efficacy of current ACIP guidelines for the prevention and control of influenza in nursing home populations are uncertain. An outbreak of influenza A/Sichuan (H3N2) in a teaching nursing home during 1988 gave us the opportunity to evaluate the effectiveness of an influenza vaccination and amantadine prophylaxis protocol. Over 13 days, 12 of 60 residents developed influenza. Prior influenza vaccination had been given to 94% of the residents. Protection from infection occurred in those tested who had antibody levels greater than or equal to 1:16 to the A/Leningrad (H3N2) antigen contained in the standard 1987-88 trivalent vaccine. However, five of 17 vaccinated residents who were tested had antibody levels less than or equal to 1:16 at the start of the outbreak. Amantadine (less than or equal to 100 mg/day) was given to all but one resident starting on the third day of the outbreak, and to employees starting on the sixth day of the outbreaks. Seven residents developed illness after the start of amantadine, although amantadine appeared to ameliorate their symptoms. Although amantadine was generally well tolerated by residents, employees receiving amantadine identified a high incidence of side effects and only 44% of employees took at least 70% of the prescribed amantadine. In our opinion, early detection and protocol-directed intervention probably abated a more severe influenza outbreak. Therefore we support existing recommendations that formal nursing home policies be established to ensure that residents and employees receive annual influenza vaccine and that chemoprophylaxis be used when outbreaks of influenza A are suspected.     

Occurrence of adverse effects and high amantadine concentrations with influenza prophylaxis in the nursing home

Amantadine, in a dose of 100 mg/day, is recommended for influenza prevention in older nursing home residents. We studied an influenza prevention protocol in a 98-bed community nursing home (96% female; mean age = 87.4 years). Fifty-five residents received amantadine when influenza A was confirmed. Although no further influenza cases were diagnosed, 22% experienced adverse events. Dose in mg/kg/day was significantly higher in the group experiencing adverse events (2.24 +/- 0.98 vs 1.76 +/- 0.35; P less than .01). Amantadine concentrations in 32 residents ranged from 128-5,810 ng/mL. Six residents had amantadine concentrations greater than 1,000 ng/mL. Seventy-eight percent would have qualified for further dose reduction on the basis of estimated creatinine clearance. The results suggest that adverse events may be an important problem with the 100 mg/day dose, and this dose may be excessive for influenza prophylaxis in many nursing home residents.     

Epidemiology of acute respiratory illness during an influenza outbreak in a nursing home. A prospective study

We observed an influenza epidemic caused by influenza A/Arizona/82 (H3N2) in a nursing home during 1982 to 1983. A survey indicated that 59% of the residents were immunized before the outbreak. The outbreak was observed to begin in November, peak in February, and disappear in April. A significant level of herd immunity may have accounted for the slow progression through the nursing home. In addition, serologic evidence of concurrent infection with respiratory syncytial virus, parainfluenza virus, and Mycoplasma pneumoniae was present in many residents. Epidemics of influenza in a closed, partially immunized population in a nursing home may proceed at a slower rate than in an open, largely unimmunized community. By monitoring for infection with other respiratory agents, the complex nature of the outbreak in this nursing home became evident.     

Use of influenza vaccine in nursing homes

The organization and outcome of influenza immunization programs were studied in 67 randomly or systematically selected nursing homes (8354 residents) in six states during the autumn of 1982 and/or 1983. In each home, influenza vaccine was usually offered to all residents on a voluntary basis, independent of their age, level of required nursing care, or underlying medical conditions. However, the proportion of residents who were vaccinated ranged from 8 to 98% (mean, 62% overall), with significantly lower rates in homes that also required consent from relatives (usually by return mail) than in homes that did not (P less than .00001; median, 57 versus 90%, respectively). These observations suggest that distribution of educational materials about the risks and benefits of influenza vaccine and systematic follow-up of relatives who fail to return the consent form may be useful strategies to further increase the number of nursing home residents who are immunized.     

An outbreak of influenza A (H3N2) in a well immunized nursing home population.

OBJECTIVE: To describe the epidemiologic features of an outbreak of influenza A that occurred in a skilled nursing home although over 90 percent of the resident population had previously received influenza vaccine. DESIGN: Retrospective cohort study. SETTING: Skilled nursing home facility in western New York State. PATIENTS: Nursing home residents and patient-care staff. MAIN OUTCOME MEASURE: Incidence of influenza-like illness among vaccinated versus unvaccinated nursing home residents and staff. RESULTS: Thirty-seven of 124 residents (attack rate = 30%) and 18 of 146 staff (attack rate = 12%) had an influenza-like illness. Staff illness began 16 days prior to onset among residents. Six cases of pneumonia and three influenza-related deaths occurred, all among the vaccinated residents. Ninety percent of the nursing home residents and 10% of the staff received the influenza vaccine prior to the outbreak. The calculated vaccine efficacies were minus 21% and plus 45% for residents and staff, respectively. CONCLUSION: While antigenic drift of the circulating influenza virus was the major factor in the apparent vaccine failure, the observed poor staff immunization rate (10%) and absence of surveillance which precluded the use of amantadine chemoprophylaxis suggest that the use of these strategies may be of importance in controlling influenza outbreaks in nursing homes.     

Influenza outbreak detection and control measures in nursing homes in the United States

OBJECTIVE: To evaluate the use of influenza vaccine, rapid influenza testing, and influenza antiviral medication in nursing homes in the US to prevent and control outbreaks. METHODS: Survey questionnaires were sent to 1017 randomly selected nursing homes in nine states. Information was collected on influenza prevention, detection and control practices, and on outbreaks during three influenza seasons (1995-1998). RESULTS: The survey response rate was 78%. Influenza vaccine was offered to residents and staff by 99% and 86%, respectively, of nursing homes. Among nursing homes offering the influenza vaccine, the average vaccination rate was 83% for residents and 46% for staff. Sixty-seven percent of the nursing homes reported having access to laboratories with rapid antigen testing capabilities, and 19% reported having a written policy for the use of influenza antiviral medications for outbreak control. Nursing homes from New York, where organized education programs on influenza detection and control have been conducted for many years, were more likely to have reported a suspected or laboratory-confirmed influenza outbreak (51% vs 10%, P = .01), to have access to rapid antigen testing for influenza (92% vs 63%, P = .01), and to use antivirals for prophylaxis and treatment of influenza A for their nursing home residents (94% vs 55%, P = .01) compared with nursing homes from the other eight states. CONCLUSIONS: Influenza outbreaks among nursing home residents can lead to substantial morbidity and mortality when prevention measures are not rapidly instituted. However, many nursing homes in this survey were neither prepared to detect nor to control influenza A outbreaks. Targeted, sustained educational efforts can improve the detection and control of outbreaks in nursing homes.     

Upper respiratory tract infection and serum antibody responses in nursing home patients

Residents of a Veterans Administration nursing home care unit (NHCU) were observed for the development of upper respiratory tract infection (URI) during 12 consecutive months to determine the frequency of sporadic cases or outbreaks of URI and to characterize them clinically and by laboratory means. Fifty-nine episodes of URI occurred in 56 residents during the study period. Serologic testing or virus isolation proved or suggested an etiologic agent on 22 occasions. URI was more common in late Fall and Winter and was caused by various agents, including influenza, Mycoplasma pneumoniae, respiratory syncytial virus, and parainfluenza viruses. A minor outbreak of influenza B in February 1986 contrasted with previous cases of URI in that the patients had a higher mean temperature and abnormal breath sounds, and they were clinically sicker. This suggests that clinical and epidemiologic surveillance during the influenza season may allow the early recognition of influenza in elderly nursing home residents. Over a 4-year period 147 serum antibody responses after influenza infection or influenza vaccination were compiled. Antibody responses to individual influenza vaccine components were measured 75 to 90 days after vaccination. The geometric mean titer (GMT) and the percentage of samples with antibody levels greater than 1:40 were determined for each of the three antigenic subtypes on 3 consecutive years. The GMT to individual vaccine components was consistently greater than 1:40, except to influenza B/Singapore in 1984 and A/Chile and B/U.S.S.R. in 1985, when these subtypes were first included in the vaccine, suggesting the NHCU residents responded less vigorously to unfamiliar vaccine subtypes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Experience with oseltamivir in the control of a nursing home influenza B outbreak.

Oseltamivir prophylaxis was very effective in protecting nursing home residents from ILI and in halting this outbreak of influenza B. A portion of the total ILI cases may have been due to influenza A, as this strain was isolated in one resident. The 10% attack rate in this facility, controlled with oseltamivir, compares favourably with another influenza B outbreak in a similar facility in the same region, over the same time frame (ILI onset 27 December to 17 January). Oseltamivir prophylaxis was not used to manage this second outbreak of laboratory-confirmed influenza B. Of the 236 residents, 45 developed ILI for an overall attack rate of 19%, nearly double the rate in the oseltamivir-controlled setting (10%). While oseltamivir was effective in controlling influenza B in this outbreak, further experience and evaluation is required before it can be routinely recommended for prophylaxis of influenza in nursing home outbreaks. Although earlier attempts by others using oseltamivir in the control of influenza A outbreaks have also met with success, it is not yet licensed for this purpose. Compared to amantadine, oseltamivir has a relatively high cost for the control of influenza A outbreaks and this may continue to limit its wider acceptance. The cost-effectiveness of oseltamivir in the control of influenza B outbreaks needs to be specifically addressed given the typically milder nature of influenza B strains. However, such a distinction is not clinically reliable and elderly residents of long-term care facilities remain vulnerable to serious complications associated with influenza infection in general. An alternate agent for influenza chemoprophylaxis that is effective against both influenza A and B, is easily administered and has few side effects, could greatly enhance current prevention and control measures and warrants serious assessment. The spread of this outbreak from the geographically separate ward to other areas of the facility in which residents had not received prophylaxis, underscores the likely role of staff as a vehicle for transmission during facility outbreaks. While accurate staff ILI rates could not be determined, their immunization rates were low, and many staff were ill during the outbreak. Isolation of residents with ILI and prophylaxis of non-ill residents on the initial outbreak wards was insufficient to prevent the spread of the outbreak, although it was subsequently halted once prophylaxis was extended to all residents. In view of the uncertainty over this medication's widespread use, in the absence of licensure or previous studies demonstrating its effectiveness in the prophylaxis and control of influenza B outbreaks, initiation of oseltamivir prophylaxis was staggered by ward. In a declared influenza A outbreak, the protocol in a long term care facility is to initiate amantadine prophylaxis on all residents, rather than ward-by-ward. While anti-viral prophylaxis may be an effective secondary control measure in the management of influenza outbreaks, optimal primary prevention would be more effective. This would require increased vaccine coverage of residents and particularly of staff, who play an important role in the importation and transmission of influenza within these facilities.     

The effect of culture-positive influenza type A on resource use and adverse events in nursing home residents

OBJECTIVES: To determine adverse clinical events and resource utilization associated with culture-positive influenza A in nursing home residents. DESIGN: A retrospective cohort study with cases and controls. SETTING: Seven hundred twenty-one-bed skilled nursing facility. PARTICIPANTS: One hundred fifty-four residents (21% of all residents) from whom influenza A was isolated during the 1997/98 season and matched controls. MEASUREMENTS: Baseline parameters, staff interventions, diagnostic tests, and adverse events were recorded from 60 days before to 60 days after specimen collection. The difference between each individual's before and after measurements determined excess utilization secondary to influenza. Controls were studied to determine time series effects. RESULTS: Baseline Minimum Data Set and nutritional parameters demonstrated significantly greater (P <.05) feeding dependency and lower serum albumin in the control group. Time series effects in the control group were negligible. Among cases, there were nine deaths within 30 days; among controls, there were four (chi2 P =.26). Within 30 days of onset, an average excess of 18 notations by nursing staff, one phone call to the physician, and one to family was noted per case. In half of cases, a nonscheduled physician visit was required. There was a 20% excess in physician orders for oxygen and bronchodilators. Chest x-rays were performed in half of the cases, and antibiotics were prescribed to half. Sixteen percent of cases had radiographic pneumonia, and 2% had congestive heart failure. The average cost for excess chest x-rays, laboratory services, antimicrobials, ambulance calls, hospital days, and emergency room and physician visits was $943.44. This does not include efforts by nursing home staff who accommodate functional decline on-site. CONCLUSION: An unexpected finding was that there were more impaired individuals who were less likely to have influenza detected or less likely to acquire influenza in the control group than in the influenza group. The morbidity, mortality, excess staff effort, and measured expenditure justify efforts to prevent influenza.     

Emergence and transmission of amantadine-resistant influenza A in a nursing home

OBJECTIVES: To prospectively detect amantadine-resistant influenza when amantadine was used for influenza A outbreak control. DESIGN: Prospective clinical surveillance and viral culture of all new respiratory illnesses during the course of amantadine prophylaxis. SETTING: A 721-bed, 14-ward nursing home for veterans and spouses during an influenza A outbreak (1993-94). PARTICIPANTS: Residents of a veterans hospital and their spouses. MEASUREMENTS: Nasopharyngeal and throat viral culture. All residents with positive cultures who developed new respiratory symptoms while receiving or residing on a unit receiving amantadine prophylaxis had antiviral-resistance testing and polymerase chain reaction restriction analyses performed. RESULTS: Amantadine prophylaxis was administered sequentially on nine of 14 wards to all well residents for 14 to 31 days/ward to control influenza outbreaks between December 9, 1993, and January 28, 1994. Amantadine treatment was simultaneously provided to 29 ill residents. Between December 3, 1993, and January 22, 1994, 68 culture-positive cases of influenza A were detected. Twenty subjects were receiving or residing on units receiving amantadine prophylaxis. Amantadine sensitivity testing could be performed on 16 residents; 12 residents had amantadine resistant strains. Four of the 12 had not received any antiviral treatment. Illness onset ranged from 1 to 22 days after amantadine prophylaxis was begun on the individual's unit. Two ribonucleic acid (RNA) mutations in the gene coding the M2 protein transmembrane region were observed that were clustered in time and space. Isolates from two roommates, one receiving amantadine for 18 days and one on no antiviral, had identical RNA sequences. CONCLUSION: Antiviral resistance may be responsible for failure of prophylaxis in nursing home outbreaks. Strategies that use different classes of antivirals for prophylaxis and treatment may limit emergence and transmission of resistant virus.     

Efficacy of Influenza Vaccine in Elderly Persons in Welfare Nursing Homes: Reduction in Risks of Mortality and Morbidity During an Influenza A (H3N2) Epidemic

BACKGROUND: The effect of influenza vaccination on the occurrence and severity of influenza virus infection in a population residing in nursing homes was studied through a program by the Osaka Prefectural Government, which is the first and official support for influenza vaccination of the elderly population during an influenza A (H3N2) epidemic in JAPAN: METHODS: A cohort study located in the Osaka Prefecture, Japan, followed the outcomes of elderly nursing home residents who received influenza vaccinations (n = 10,739) in comparison with control subjects who did not receive influenza vaccinations (n = 11,723) and monitored clinically the onset of serious morbidity and mortality of influenza illness. Subjects were 22,462 persons older than 65 years who resided in 301 welfare nursing homes in the Osaka Prefecture, Japan during an influenza A (H3N2) epidemic in 1998 to 1999. RESULTS: Of 22,462 individuals living in 301 nursing homes, 10,739 received either one dose (2027 subjects) or two doses (8712 subjects) of inactivated, subunit trivalent influenza vaccine. Through the period from November 1998 to March 1999, there were 950 cases of influenza infection diagnosed clinically with cases by virus isolation and/or serology. There were statistically significantly fewer clinical cases of influenza, hospital admissions due to severe infection, and deaths due to influenza in the vaccinated cohort (256 cases, 32 hospital admissions, and one death) compared with the unvaccinated controls (694 cases, 150 hospital admissions, and five deaths). Vaccination was equally effective in those who received one dose of vaccine as in those who received two doses. No serious adverse reactions to vaccination were recorded. Thus, influenza vaccination is safe and effective in this population and should be an integral part of the routine care of persons aged 65 years and older residing in nursing homes. CONCLUSIONS: This study provides an analysis of the clinical efficacy of influenza vaccination in a large cohort of nursing home residents in JAPAN: Annual influenza vaccine administration requires the attention of all nursing home attendants, physicians, and public health organizations.     

Amantadine usage for influenza A during an influenza outbreak in a nursing home

An outbreak of an influenza like illness was found in a nursing home in Fukuoka in January, 1999. Results of hemagglutinin inhibition tests with paired sera of patients and rapid diagnosis kit for influenza A indicated that an influenza A (H3N2) outbreak had occurred. A total of 15 patients with influenza like illness from one residential area of the nursing home were administered amantadine, 100 mg per day for five days. Clinical records of 264 residents were surveyed retrospectively from the tenth to the thirty-first of January, 1999. Influenza like illness was found in 112 residents (42.4%). The incidence of influenza like illness differed by residential area, ranging from 27.6% to 54.0%. The mean duration of fever was 3.6 days among patients administered amantadine. The mean duration was 4.4 days for patients not administered amantadine. The incidence of influenza like illness decreased rapidly after amantadine administration in the residential area where amantadine administration was done. These results suggest that amantadine is effective in mitigating influenza symptoms in the elderly. Amantadine may be useful for diminishing the influence of influenza A outbreaks in nursing homes.     

Experience with oseltamivir in the control of nursing home influenza A outbreak

OBJECTIVE: Influenza outbreaks have revealed that elderly persons are a great risk of death and serious complications after infection. The administration of oseltamivir, a neuramidase inhibitor, is effective for prophylaxis of influenza and to reduce disease duration and severity in healthy adults with naturally acquired febrile influenza. To clarify the usefulness of oseltamivir in the elderly we administered oseltamivir to all residents when an influenza A outbreak occurred in a nursing home. PATIENTS: Sixty-eight residents in the nursing home were investigated in which the influenza A outbreak occurred; 32 residents had fever and 28 residents were positive for influenza A with direct enzyme immunoassay. METHODS: Oseltamivir was administered at 75 mg twice daily for 5 days to all residents. RESULTS: Oseltamivir almost inhibited symptom onset in the influenza A-positive afebrile group. Initiation at 0 hour (22 cases), 1-12 hours (4 cases), 13-24 hours (5 cases) or 72 hours (1 case) from onset of symptoms was associated with mean fever durations of 26+/-18 hours, 38+/-21 hours, 54+/-12 hours and 120 hours, respectively, indicating that earlier initiation of therapy was associated with faster resolution of fever in elderly patients. Oseltamivir may be effective for household prophylaxis in the elderly persons. Oseltamivir administration was well tolerated in elderly persons. CONCLUSION: Oseltamivir is effective for the reduction or prophylaxis of influenza A infection in elderly persons.     

Adverse reactions to amantadine prophylaxis of influenza in a retirement home

OBJECTIVE: Controversy exists about the safety of following the recommendation of the Immunization Practice Committee of the Centers for Disease Control that nursing home residents be given amantadine prophylaxis during influenza outbreaks. This study was undertaken to define the incidence of adverse reactions to amantadine in the elderly and to identify risk factors for side effects. DESIGN: A retrospective cohort study. SETTING: A retirement home which offered amantadine prophylaxis to its residents during a presumed influenza outbreak. PARTICIPANTS: Of the 96 elderly residents, 79 accepted the offer of amantadine prophylaxis. MAIN OUTCOME MEASURES: Attributable adverse health outcomes as assessed by chart review. RESULTS: 41% of the people receiving amantadine had attributable adverse reactions, of which 22% were classified as severe. Severe adverse reactions were associated with residence in the assisted living section of the facility (P = 0.002), a greater number of underlying diagnoses (P = 0.009), congestive heart failure (P = 0.02), and high serum creatinine (P = 0.02). A person with none of these risk factors had a 7% chance of having a severe adverse outcome compared to a 70% chance for someone with all four risk factors. CONCLUSION: The findings raise concern that the prophylactic administration of amantadine to all elderly residents of nursing and retirement homes may be associated with a high incidence of unacceptable reactions, particularly among less healthy residents.     

Prevention and control of type A influenza infections in nursing homes. Benefits and costs of four approaches using vaccination and amantadine

We developed a model to project morbidity, mortality, and costs attributable to type A influenza virus infections in nursing homes and to evaluate the relative benefits and costs of programs for prevention and control. Influenza vaccination was the most cost-effective intervention under various simulations in the model but usually allowed for higher rates of morbidity and mortality compared with other alternatives. The combined use of previous vaccination and chemoprophylaxis during outbreaks in the nursing home was associated with significantly fewer cases than use of vaccination alone, with only modest increases in net program costs. The use of chemoprophylaxis throughout the influenza season (without vaccination) resulted in the fewest number of illnesses, hospitalizations, and deaths but would cost at least 650% more than alternatives involving vaccination. Regardless of which strategy is chosen, our model suggests that influenza control programs in nursing homes are both beneficial and cost-effective and should be considered a part of standard care.     

Use of oseltamivir during influenza outbreaks in Ontario nursing homes, 1999-2000

OBJECTIVES: To describe the experience of Ontario long-term care facilities that used oseltamivir during influenza outbreaks in 1999/2000. DESIGN: Case series. SETTING: Ten Ontario long-term care facilities for older people and their residents. PARTICIPANTS: Older residents of long-term care facilities. INTERVENTION: Oseltamivir for treatment or prophylaxis during 11 influenza outbreaks in 1999/2000. MEASUREMENTS: Control of outbreaks; pneumonia, hospitalization, and death complicating acute influenza. RESULTS: All outbreaks were due to influenza A//H3N2/Sydney/05/97. One facility elected to use oseltamivir for treatment and amantadine for prophylaxis. The remaining nine facilities (10 outbreaks) recommended oseltamivir for treatment and prophylaxis (after amantadine failure in five and as primary prophylaxis in five). Use of oseltamivir was associated with termination of the outbreak in all eight evaluable outbreaks. Overall, 178/185 (96%) case-residents met the case definition of influenza and had complete data for evaluation. Of these, 63 (35%) were treated with antibiotics, 37 (21%) were diagnosed with pneumonia, 19 (11%) were hospitalized, and 16 (9%) died. Compared with residents receiving no therapy or who became ill while taking amantadine, residents who received oseltamivir within 48 hours of the onset of symptoms were less likely to be prescribed antibiotics, to be hospitalized, or to die (P <.05 for each outcome). These differences persisted and remained statistically significant when corrected for influenza immunization status. A total of 730 residents received oseltamivir prophylaxis for a median of 9 days (range 5-12). Of these, side effects were identified in 30 (4.1%), the most common being diarrhea (12 residents, 1.6%), cough (5, 0.7%), confusion (4, 0.5%) and nausea (4, 0.5%). CONCLUSIONS: Oseltamivir is safe and appears to be effective when used as treatment or prophylaxis to control outbreaks of influenza in older nursing home residents.     

Incontinence-associated skin damage in nursing home residents: a secondary analysis of a prospective, multicenter study

More than half of the nursing home population is incontinent of urine or feces, presenting challenges to perineal skin health. To determine the occurrence and severity of skin damage in nursing home residents with incontinence, a secondary analysis of data collected from a multisite, open-label, quasi-experimental study of cost and efficacy of four regimens for preventing incontinence-associated dermatitis in nursing home residents was performed. Sixteen randomly selected nursing homes from across the US were included in the study. Participating nursing home residents were incontinent of urine and/or feces and free of skin damage. Of the 1,918 persons screened, 51% (n = 981) qualified for prospective surveillance. Perineal skin was assessed over a 6-week period; frequency, type, and severity of skin damage were observed. Skin damage developed after a median of 13 (range 6 to 42) days in 45 out of 981 residents (4.6%), of which 3.4% was determined to be incontinence-associated dermatitis. Some residents (14 out of 45, 31%) had incontinence-associated dermatitis of other skin damage in more than one area. This study is one of the first to report the characteristics of incontinence-associated dermatitis in a large sample of nursing home residents. The sample size and random selection of nursing homes impart generalizability to the findings. Incontinence-associated dermatitis is a risk in nursing home residents, especially those with fecal incontinence. These findings suggest that the rate and severity of incontinence-associated dermatitis are low with close monitoring and use of a defined skin care regimen that includes a pH-balanced cleanser and moisture barrier.     

Hospitalizations and deaths due to respiratory illnesses during influenza seasons: a comparison of community residents,senior housing residents,and nursing home residents

BACKGROUND: Although research indicates that influenza is a major cause of morbidity and mortality among older adults, few studies have tried to identify which seniors are particularly at risk of experiencing complications of influenza. The purpose of this study was to compare hospitalizations and deaths due to respiratory illnesses during influenza seasons among seniors (aged 65+) living in the community, senior residences (apartments reserved for seniors), and nursing homes. METHODS: Using administrative data, all hospital admissions and deaths due to respiratory illnesses (pneumonia and influenza, chronic lung disease, and acute respiratory diseases) were identified for all individuals aged 65 and older living in Winnipeg, Canada (approximately 88,000 individuals) during four influenza seasons (1995-1996 to 1998-1999). RESULTS: Hospitalization and death rates for respiratory illnesses increased significantly during influenza seasons, compared to fall periods (e.g., 42.7 vs 25.2 hospitalizations per 1000 population aged 80 and older). Moreover, hospitalization rates for pneumonia and influenza, chronic lung disease, and acute respiratory diseases were higher among individuals living in senior residences (42.5 per 1000 for all respiratory illnesses combined) than their counterparts living in the community (22.8 per 1000). Furthermore, deaths due to pneumonia and influenza and chronic lung disease were higher among senior housing residents (4.2 per 1000) than community residents (2.6 per 1000) and were particularly high among nursing home residents (52.1 per 1000). CONCLUSIONS: Individuals living in seniors residences are at increased risk of being hospitalized for and dying of respiratory illnesses during influenza seasons. Given that influenza vaccination is currently the best method to reduce influenza-associated illnesses among seniors, this suggests that influenza vaccination strategies should be targeted at this population.     

Effect of Influenza Vaccination of Nursing Home Staff on Mortality of Residents: A Cluster-Randomized Trial

OBJECTIVES: To evaluate the effect of staff influenza vaccination on all-cause mortality in nursing home residents.
DESIGN: Pair-matched cluster-randomized trial.
SETTING: Forty nursing homes matched for size, staff vaccination coverage during the previous season, and resident disability index.
PARTICIPANTS: All persons aged 60 and older residing in the nursing homes.
INTERVENTION: Influenza vaccine was administered to volunteer staff after a face-to-face interview. No intervention took place in control nursing homes.
MEASUREMENTS: The primary endpoint was total mortality rate in residents from 2 weeks before to 2 weeks after the influenza epidemic in the community. Secondary endpoints were rates of hospitalization and influenza-like illness (ILI) in residents and sick leave from work in staff.
RESULTS: Staff influenza vaccination rates were 69.9% in the vaccination arm versus 31.8% in the control arm. Primary unadjusted analysis did not show significantly lower mortality in residents in the vaccination arm (odds ratio=0.86, P =.08), although multivariate-adjusted analysis showed 20% lower mortality ( P =.02), and a strong correlation was observed between staff vaccination coverage and all-cause mortality in residents (correlation coefficient=−0.42, P =.007). In the vaccination arm, significantly lower resident hospitalization rates were not observed, but ILI in residents was 31% lower ( P =.007), and sick leave from work in staff was 42% lower ( P =.03).
CONCLUSION: These results support influenza vaccination of staff caring for institutionalized elderly people.