Peggy Krause

Efficacy of zanamivir for chemoprophylaxis of nursing home influenza outbreaks

Despite vaccination, influenza remains a common of morbidity in nursing homes. Chemoprophylaxis of residents with currently available antivirals is not always effective and new agents effective against both influenza A and B are needed. In a randomized, unblinded pilot study, we compared 14 day chemoprophylaxis with zanamivir, an antiviral which inhibits influenza neuraminidase, to standard of care during sequential influenza A and influenza B outbreaks in a 735 bed nursing home. Influenza A outbreaks were declared on 6/14 epidemic units. Sixty-five volunteers on four epidemic units were randomized to zanamivir and on two epidemic units, 23 volunteers were randomized to rimantadine. During the 14 days of prophylaxis, only four new febrile respiratory illnesses were detected. One volunteer receiving rimantadine prophylaxis developed laboratory-confirmed influenza. Influenza B outbreaks were declared on 3/14 epidemic units. Thirty-five volunteers on two epidemic units were randomized to zanamivir and 18 volunteers on one epidemic unit were randomized to no drug. During the 14 days of prophylaxis, only one new febrile respiratory illness was detected. One volunteer randomized to receive no drug developed laboratory-confirmed influenza. Zanamivir appears comparably effective to standard of care in preventing influenza-like illness and laboratory-confirmed influenza in nursing homes, but requires further testing.

Report of an Outbreak: Nursing Home Architecture and Influenza-A Attack Rates

OBJECTIVE To determine factors that might account for a significantly lower attack rate in a newly constructed nursing building during an epidemic of type A influenza. SETTING A four-building, long-term care facility for veterans and their spouses, with an average daily census of 690. DESIGN Prospective surveillance with retrospective analysis. PARTICIPANTS Symptomatic residents submitting to viral culture. MEASUREMENTS Number of respiratory illnesses and influenza cultures in consenting symptomatic residents. Building characteristics. RESULTS An influenza A (H3N2) outbreak was culture-confirmed in 68 nursing home residents. Influenza A was isolated in 3/184 (2%) residents in Building A, 31/196 (16%) in Building B, 18/194 (9%) in Building C, and 16/116 (14%) in Building D. Denominators are average daily census during the outbreak. Building A had significantly fewer culture-confirmed cases than the other buildings (P < .001). Fewer residents in Building A, 47% compared with 61% in Buildings B, C, and D, were participants in a formal study of influenza. Eight of 15 respiratory illnesses identified during the outbreak that were not cultured occurred in Building A. These factors could not account for the difference in attack rates. Building A has a unique ventilation system, more square feet of public space per resident, and does not contain office space that serves the entire four-building facility. CONCLUSION Our retrospective observation suggests that architectural design may influence the attack rate of influenza A in nursing homes.

Pneumonia in a nursing home

The authors studied nursing home residents serologically to determine whether atypical organisms were causes of radiologic pneumonia. The study was conducted at the Wisconsin Veterans Home, a facility with on-site microbiology and x-ray. Over one year, serologic examinations for Legionella, Mycoplasma, and Chlamydia were conducted for the residents who had pneumonia. Cultures and mortality were reviewed. Fifty-six episodes were studied (mean resident age 78 years). There was no fourfold titer change. Seventeen quality sputum specimens revealedStreptococcus pneumoniae (5), normal flora (4),Hemophilus influenzae (4),Moraxella catarrbalis (3),Staphylococcus aureus (1), and beta-hemolytic Streptococcus, not group A (1). The two-month mortality was 21%. This study did not result in serologic confirmation of atypical organisms’ causing pneumonia. Antibiotic choice should be based on coverage of prevalent organisms, includingHemophilus influenzae, Moraxella, and Staphylococcus, as well as clinical features.

Granzyme B: a marker of risk for influenza in institutionalized older adults.

Risk for influenza increases with age while cellular immune responses decline. This was a prospective study to determine the relationship between cytokine and granzyme B levels in peripheral blood mononuclear cells stimulated with live influenza virus, and subsequent influenza illness. Granzyme B levels were lower in the group who later developed symptomatic laboratory-confirmed influenza (n=10) compared to the group who did not (n=90) (ANOVA, P=0.024). In contrast, none of the cytokine levels were related to the development of influenza. Thus, granzyme B is a potential marker of influenza risk in older adults.

Non-influenza respiratory viruses may overlap and obscure influenza activity

OBJECTIVE: To report the number and timing of influenza A isolates, as well as overlapping respiratory viruses. Co‐circulating respiratory viruses may obscure the determination of influenza activity.

Mortality following isolation of various respiratory viruses in nursing home residents

OBJECTIVE To compare mortality following isolation of influenza A to mortality following isolation of other respiratory viruses in a nursing home. SETTING The Wisconsin Veterans Home, a 688-bed skilled nursing facility for veterans and their spouses. PARTICIPANTS All residents with respiratory viral isolates obtained between 1988 and 1999. DESIGN Thirty-day mortality was determined following each culture-proven illness. RESULTS Thirty-day mortality following isolation of viral respiratory pathogens was 4.7% (15/322) for influenza A; 5.4% (7/129) for influenza B; 6.1% (3/49) for parainfluenza type 1; 0% (0/26) for parainfluenza types 2, 3, and 4; 0% (0/26) for respiratory syncytial virus (RSV); and 1.6% (1/61) for rhinovirus. CONCLUSIONS Mortality following isolation of certain other respiratory viruses may be comparable to that following influenza A (although influenza A mortality might be higher without vaccination and antiviral agents). The use of uniform secretion precautions for all viral respiratory illness deserves consideration in nursing homes.

Immune response to influenza vaccination in institutionalized elderly: effect on different T-cell subsets

Humoral and cellular immunological responses to influenza vaccination were measured in volunteers in a long-term care facility. All participants were vaccinated with the commercially available 1994-95 trivalent influenza vaccine and blood samples were collected before and 6 and 12 weeks after vaccination. Cytokine and granzyme B in peripheral blood mononuclear cell (PBMC) cultures after virus stimulation, and serum antibody titres were measured for each of these time points. In general, the measures of the immunological response to vaccination were low and variably significant. The major finding was the difference with respect to post-vaccination measures for the two strains of influenza A contained in the vaccine. Geometric mean antibody titres were significantly higher for A/Texas/36/91 at all time points in the study when compared to A/Shangdong/09/93. There was a corresponding rise for interleukin-10 (IL-10) to the A/Texas/36/91 strain while no increase in IL-10 was observed in A/Shangdong/09/93-stimulated cultures after vaccination. In contrast, granzyme B rose after vaccination only in cultures stimulated with A/Shangdong/09/93. Interferon-gamma levels were also significantly higher in these PBMC cultures. There was a poor interleukin-2 (IL-2) response to both strains of influenza A. These data suggest that different strains or subtypes of influenza A may preferentially enhance T-helper type 1 versus type 2 responses through vaccination in institutionalized seniors.

Between‐Meal Risedronate Does Not Alter Bone Turnover in Nursing Home Residents

OBJECTIVES: To assess the effect of between‐meal weekly risedronate and daily calcium 630 mg and vitamin D 400 IU on bone turnover markers.

Position-related changes in voiding dynamics in men.

OBJECTIVES To investigate by urodynamic study position-related changes in uroflowmetry and postvoid residual urine volume (PVR) in men because altered bladder function in the supine position may be a predisposing factor for urinary tract infections in the institutionalized elderly. METHODS Two healthy men, 34 and 59 years of age and living at home, and 53 nursing home residents (mean age 71.8 years, range 46 to 92) were evaluated with uroflowmetry in the standing and recumbent positions (lying on the left or right side); corresponding PVRs were measured by transabdominal ultrasonic bladder scanning. The two healthy men were monitored longitudinally with multiple recordings in both voiding positions, and the nursing home residents were subjected to two observations: one measurement of the variable parameters in either position. Differences were considered to be significant at P < 0.05. RESULTS The 34-year-old man performed 51 3 flows (368 standing and 145 recumbent). The mean of all the peak flow rates in the upright (28.2 +/- 4.2 mL/s) versus the recumbent (16.8 +/- 4.1 mL/s) position revealed a highly significant difference (P = 0.0001). Sixteen urinary flows and corresponding PVRs were completed by this subject in either voiding position. The difference between PVRs in the standing (13.1 +/- 14.7 mL) versus recumbent (15.3 +/- 17.5 mL) position was not statistically significant. The 59-year-old man completed 156 flows (128 standing and 28 recumbent). A highly significant difference was noted between the mean of all peak flows in the upright (18.9 +/- 4.1 mL/s) versus recumbent (12.6 +/- 2.0 mL/s) position (P = 0.0001). Thirty-seven urinary flows and corresponding PVRs were completed by this individual (10 PVRs were determined after voiding in the standing and 27 after voiding in the recumbent position). No significant difference was noted between PVRs in the standing (24.6 +/- 34.4 mL) versus recumbent (16.5 +/- 60.0 mL) position. In the nursing home residents, the difference between the mean peak flow rates in the standing (14.5 +/- 8.6 mL/s) versus recumbent (12.4 +/- 6.7 mL/s) position also reached statistical significance (P = 0.0084). The difference between PVRs in the standing (60.5 +/- 125.6 mL) versus recumbent (84.8 +/- 186.2 mL) position barely reached statistical significance (P = 0.0497). CONCLUSIONS The urinary flow rate decreases in the recumbent position. Bedridden residents may be predisposed to urinary tract infections because of alterations in voiding dynamics in the supine position. This area needs further study.

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.