Sequential outbreak of influenza A and B in a nursing home: efficacy of vaccine and amantadine.
OBJECTIVE
To describe the sequential occurrence of influenza A and B in a nursing home, and to determine the efficacy of influenza vaccine and/or amantadine treatment with respect to incidence and sequelae.


METHODS
The Jewish Home and Hospital for Aged, a skilled-care nursing facility.


METHODS
Of 499 frail older nursing home residents, 139 contracted influenza during the study period (mean age 87.5 years; SD = 6.7). The residents were followed from February through April 1988.


METHODS
Influenza vaccine and/or amantadine.


METHODS
Episodes of influenza and their sequelae, i.e., pneumonia, hospitalization, and death.


RESULTS
The vaccine had no effect on the incidence of influenza-like illness, length of illness, or the associated death rate. It reduced the rate of pneumonia secondary to influenza A and B (relative risk = .57; 95% CI: .37 to .89; P = .023). Amantadine did not affect the attack rate of influenza nor the rate of pneumonia secondary to influenza. It was associated with decreased mortality (relative risk = 0; P = .001), and shorter length of influenza A illness (PWilcoxon = .082). Although the combination of amantadine and vaccine did not affect length of influenza (A or B) illness, it was associated with a significantly lower rate of sequelae (relative risk = .58; 95% CI: .36 to .95; P = .024).


CONCLUSIONS
In this epidemic, the combination of amantadine and vaccine was most effective in reducing the rate of influenza-associated sequelae. The possibility of a "biphasic" epidemic prompts consideration of vaccinating nonimmunized nursing home residents, even though it may be late in the influenza season.
Libow
L S
LS
Jewish Home and Hospital for Aged of New York, NY 10025, USA.
Neufeld
R R
RR
Olson
E
E
Breuer
B
B
Starer
P
P
D000368:Aged; D000369:Aged, 80 and over; D000547:Amantadine / Q000627:therapeutic use*; D004196:Disease Outbreaks; D016330:Frail Elderly; D006707:Homes for the Aged; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D009980:Influenza A virus; D009981:Influenza B virus; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology* / Q000628:therapy*; D009519:New York City / Q000453:epidemiology; D009735:Nursing Homes; D011014:Pneumonia / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D012189:Retrospective Studies
D007252:Influenza Vaccines; D000547:Amantadine