Re: Japan : H3N1 reassortment fatalites or drift variant?
Re: Japan : H3N1 reassortment fatalites or drift variant?
note: 1985 influenza outbreaks in Connnecticut
Epidemiologic Notes and Reports Outbreaks of Influenza among Nursing Home Residents -- Connecticut, United States
Archived epidemiological study of H3N2 outbreaks in Nursing Homes without drift, shift or reassortment.
From publication:
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Outbreak 1. Nineteen residents of a skilled-care nursing facility had influenza-like illnesses. Ages ranged from 65 years to 94 years (median 84 years). Six of seven ill persons had fourfold or greater rises in hemagglutination-inhibition (HI) antibody against influenza A(H3N2) viruses but no comparable rises against other respiratory pathogens. Residents of only one floor of the facility became ill. On the affected floor, the
attack rate was 25% (19/75); the rate was 26% (15/57) for vaccinated persons; 19% (3/16) for unvaccinated persons; and 50% (1/2) for residents whose vaccination status was unknown. None of these differences were statistically significant (p
0.05).
Outbreak 2. Twenty-six residents of a skilled-care nursing facility had influenza-like illnesses. Ages ranged from 33 years to 95 years (median 83 years). One of 14 throat swabs collected from ill residents yielded influenza A(H3N2) virus similar to A/Philippines/2/82. All six ill residents from whom serum specimens were obtained had fourfold or greater rises in HI antibody against influenza A(H3N2). The
overall attack rate was 31% (26/85); the rate was 40% (12/30) for vaccinated persons and 25% (14/55) for unvaccinated persons (p
0.05). Vaccinated persons did not differ from unvaccinated persons in terms of age, sex, or level of needed care. After 41 (66%) of the remaining 62 well residents were started on amantadine hydrochloride prophylaxis (100 mg/day), only one, a resident who had not received amantadine, became ill.
Outbreak 3. One hundred eleven residents of a large multiple level-of-care facility had influenza-like illnesses. Ages ranged from 64 years to 104 years (median 85 years). One of six throat swab specimens yielded influenza A(H3N2) virus similar to A/Philippines/2/82. Fourteen of 18 ill residents from whom paired sera were obtained had fourfold or greater rises in antibody against influenza A(H3N2). The
overall attack rate was 23% (111/489); the rate was 22% (75/336) for vaccinated persons; 20% (25/128) for unvaccinated persons; and 44% (11/25) for residents whose vaccination status were unknown (p
0.05). After the widespread institution of amantadine hydrochloride prophylaxis (100 mg/day) for residents and staff members, three additional cases were identified among residents on amantadine.
Ten influenza-related deaths were reported from all three nursing homes. Because of small numbers, statistically significant differences between vaccinated and unvaccinated influenza patients were not detected for length of illness, frequency of hospitalization, development of pneumonia, or risk of death.
Outbreak 4. A fourth influenza A(H3N2) outbreak in Connecticut was investigated by local personnel. Fourteen (23%) of 60 nursing home residents requiring intermediate care were affected, including 10 (20%) of 49 vaccinated persons and four (36%) of 11 unvaccinated persons (p
0.05).
One influenza-related death was reported.
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