The roles of vaccination and amantadine prophylaxis in controlling an outbreak of influenza A (H3N2) in a nursing home.
An outbreak caused by influenza A/Philippines/2/82 (H3N2)-like viruses occurred in a partially vaccinated nursing home population in January 1985. During the first six days of the outbreak, 14 (25%) of 55 residents developed influenzalike illness. The risk of illness was most strongly associated with undetectable levels of antibody against the epidemic strain, with unvaccinated case-patients having more severe illnesses and a higher rate of hospitalization than vaccinated case-patients (5/8 vs 0/6). During the period of amantadine hydrochloride prophylaxis (100 mg/d) from days 7 to 35, only two (5%) of the remaining 41 residents became ill, even though 11 (27%) had no detectable antibody. Serum amantadine levels obtained on day 35 ranged from 117 to 737 ng/mL (mean 309 ng/mL), similar to therapeutic levels documented in younger adults who have taken the standard regimen of 200 mg/d; there were few clinically significant side effects. These findings illustrate the benefits of influenza vaccination and support the use of amantadine hydrochloride at a dosage of 100 mg daily for outbreak control among elderly persons.
Arden
N H
NH
Division of Viral Diseases, Centers for Disease Control, Atlanta, GA 30333.
Patriarca
P A
PA
Fasano
M B
MB
Lui
K J
KJ
Harmon
M W
MW
Kendal
A P
AP
Rimland
D
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000547:Amantadine / Q000627:therapeutic use*; D003428:Cross Infection / Q000517:prevention & control; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D005845:Georgia; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000276:immunology*; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes; D014611:Vaccination
D007252:Influenza Vaccines; D000547:Amantadine