2005 Measles Outbreak in Indiana
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《新英格兰医药杂志》
To the Editor: Parker et al. (Aug. 3 issue)1 describe the largest documented outbreak of measles in the United States since 1996, which is of considerable epidemiologic interest. It is surprising that few of the cases were confirmed by laboratory analysis, particularly one of the two involving "vaccine failure." Could the authors explain why, with the availability of noninvasive testing methods, more patients were not tested? It is also unclear how local investigators identified the cases and whether any consideration was given to the possibility of asymptomatic infection, since there is evidence that measles may circulate in vaccinated populations and cause subclinical infection.2
Erika F. Duffell, M.F.P.H., M.P.H.
Greater Manchester Health Protection Unit
Manchester M30 0NJ, United Kingdom
References
Parker AA, Staggs W, Dayan GH, et al. Implications of a 2005 measles outbreak in Indiana for sustained elimination of measles in the United States. N Engl J Med 2006;355:447-455.
Vardas E, Kreis S. Isolation of measles virus from a naturally-immune, asymptomatically re-infected individual. J Clin Virol 1999;13:173-179.
The authors reply: We obtained laboratory confirmation for at least one patient in 9 of 11 families infected with measles. Among these 9 families, 14 of 20 patients had disease that was confirmed by laboratory analysis. The remaining two families (with 10 and 4 patients, respectively) declined to have specimens collected from all family members. The parents of the patient who had measles despite receiving two doses of vaccine declined to have specimens collected from any of their children except one whose disease was confirmed by laboratory testing during hospitalization. All patients had classic clinical symptoms of measles that appeared after the appropriate incubation period after exposure to a patient with laboratory-confirmed disease. The percentage of cases that were confirmed by laboratory testing in the Indiana outbreak (41%) was similar to that in other outbreaks among groups of persons who had declined to receive vaccination.1,2
Case finding involved contacting persons with a known exposure to measles, physician alerts, and media releases. Although the asymptomatic spread of measles could potentially occur, all but one patient had an identified source. This patient worked in a hospital where patients with measles had been treated within 14 days before the onset of her symptoms. Thus, we believe that asymptomatic transmission was unlikely to have played a major role in the Indiana outbreak.
Amy A. Parker, M.S.N., M.P.H.
Centers for Disease Control and Prevention
Atlanta, GA 30333
Wayne Staggs, M.S.
Indiana State Department of Health
Indianapolis, IN 46204
Gustavo H. Dayan, M.D.
Centers for Disease Control and Prevention
Atlanta, GA 30333
References
Hanratty B, Holt T, Duffell E, et al. UK measles outbreak in non-immune anthroposophic communities: the implications for the elimination of measles from Europe. Epidemiol Infect 2000;125:377-383.
Siedler A, Tischer A, Mankertz A, Santibanez S. Two outbreaks of measles in Germany 2005. Euro Surveill 2006;11:131-134.
Erika F. Duffell, M.F.P.H., M.P.H.
Greater Manchester Health Protection Unit
Manchester M30 0NJ, United Kingdom
References
Parker AA, Staggs W, Dayan GH, et al. Implications of a 2005 measles outbreak in Indiana for sustained elimination of measles in the United States. N Engl J Med 2006;355:447-455.
Vardas E, Kreis S. Isolation of measles virus from a naturally-immune, asymptomatically re-infected individual. J Clin Virol 1999;13:173-179.
The authors reply: We obtained laboratory confirmation for at least one patient in 9 of 11 families infected with measles. Among these 9 families, 14 of 20 patients had disease that was confirmed by laboratory analysis. The remaining two families (with 10 and 4 patients, respectively) declined to have specimens collected from all family members. The parents of the patient who had measles despite receiving two doses of vaccine declined to have specimens collected from any of their children except one whose disease was confirmed by laboratory testing during hospitalization. All patients had classic clinical symptoms of measles that appeared after the appropriate incubation period after exposure to a patient with laboratory-confirmed disease. The percentage of cases that were confirmed by laboratory testing in the Indiana outbreak (41%) was similar to that in other outbreaks among groups of persons who had declined to receive vaccination.1,2
Case finding involved contacting persons with a known exposure to measles, physician alerts, and media releases. Although the asymptomatic spread of measles could potentially occur, all but one patient had an identified source. This patient worked in a hospital where patients with measles had been treated within 14 days before the onset of her symptoms. Thus, we believe that asymptomatic transmission was unlikely to have played a major role in the Indiana outbreak.
Amy A. Parker, M.S.N., M.P.H.
Centers for Disease Control and Prevention
Atlanta, GA 30333
Wayne Staggs, M.S.
Indiana State Department of Health
Indianapolis, IN 46204
Gustavo H. Dayan, M.D.
Centers for Disease Control and Prevention
Atlanta, GA 30333
References
Hanratty B, Holt T, Duffell E, et al. UK measles outbreak in non-immune anthroposophic communities: the implications for the elimination of measles from Europe. Epidemiol Infect 2000;125:377-383.
Siedler A, Tischer A, Mankertz A, Santibanez S. Two outbreaks of measles in Germany 2005. Euro Surveill 2006;11:131-134.