Influenza A among community-dwelling elderly persons in Leicestershire during winter 1993-4; cigarette smoking as a risk factor and the efficacy of influenza vaccination
Kg. Nicholson et al., Influenza A among community-dwelling elderly persons in Leicestershire during winter 1993-4; cigarette smoking as a risk factor and the efficacy of influenza vaccination, EPIDEM INFE, 123(1), 1999, pp. 103-108
In a prospective study of community-dwelling people 60-90 years of age, we
examined the coverage of influenza vaccine during 1992-3 and 1993-4, the ef
ficacy of vaccination in reducing serologically-confirmed clinical episodes
of influenza A during 1993, and the effect of cigarette smoking. During 19
92 and 1993, influenza vaccine was given to 106/215 (49 %) and 120/204 (59
%) people with risk conditions, and 84/225 (37 %) and 103/235 (44 %) withou
t risk conditions. Influenza vaccination and general practitioner consultat
ions during 1992 were independent predictors of vaccination in 1993, but cu
rrent smoking was a negative predictor. Of 209 unimmunized people, 8/35 (23
%) smokers had clinical influenza as compared with 11/174 (6 %) non-smoker
s (OR 4.4, 95 % CI 1.6 to 11.9). Of 371 non-smokers, 1/197 (0.5 %) vaccinee
s had influenza as compared with 11/174 (6 %) non-vaccinees (OR 0.075, 95 %
CI 0.587 to 0.009). No cases of influenza occurred among 21 current smoker
s who were vaccinated.