Decline in measles case fatality ratio after the introduction of measles immunization in rural Senegal.
نویسندگان
چکیده
The epidemiology of measles has been investigated in Niakhar, a rural area of Senegal, during two periods, 1983-1986 and 1987-1990. Following a major increase in immunization coverage beginning in 1987, the case fatality ratio for all ages declined fourfold from the first to the second period (relative risk (RR) = 0.24, 95% confidence interval (CI) 0.13-0.46). The measles incidence for children under 10 years of age declined by 69% (95% CI 65-72) and the risk of dying of measles by 91% (95% CI 82-95). Vaccinated children who contracted measles had significantly lower case fatality ratio than unvaccinated children with measles (p = 0.038). Children infected by an immunized case tended to have lower case fatality ratio than those infected by an unimmunized index case (p = 0.104) and immunized index cases generated fewer secondary cases than unimmunized index cases (p < 0.001). Respiratory complications were more common in secondary cases infected by an index case with respiratory complications than by an index case without such complications (RR = 1.60, 95% CI 1.08-2.37), which suggests that severe cases give rise to further severe cases. As expected, there was a significant increase in the proportion of vaccinated cases in the second period (RR = 1.41, 95% CI 1.00-1.98). Mean age at infection increased from 4 to 7 years between the two periods and the change in age structure accounted for 20% of the decline in case fatality ratio. Measles immunization may contribute to lower mortality directly through reduced incidence and indirectly through increases in age at infection, less severe infection for immunized cases and changes in transmission patterns leading to reduced severity of measles.
منابع مشابه
Decline in measles mortality: nutrition, age at infection, or exposure?
The mortality from measles was studied in an urban area of Guinea-Bissau one year before and five years after the introduction of a vaccination programme. The years after the introduction of immunisation saw a decline in mortality among unvaccinated children with measles. This decline occurred despite a lower age at infection and an increasing prevalence of malnourished children. State of nutri...
متن کاملMEASLES EPIDEMICS TN KERMAN, IRAN
In early 1990, an outbreak of measles occurred in Kerman, (population 257, 284) Iran. Overall, 475 cases were identified and four died (case fatality ratio 5.4 per thousand). Illness was limited primarily to children below 15 years of age 166 (22.3%) were in children under five, 573 (77%) between 5-14 and six (0.8%) above 15 years of age. The age of the cases ranged from five months to 35 y...
متن کاملEfficacy and safety of live attenuated Sugiyama strain of measles virus in mass immunization of children in rural regions of Iran
متن کامل
No long-term excess mortality after measles infection: a community study from Senegal.
Because measles immunization has been found in all studies to reduce mortality with more than the share of deaths attributed to acute measles, the authors examined mortality after measles infection in a study in a rural area of Senegal that included 6,924 unimmunized children, whom 1,118 developed measles. Age-adjusted post-measles mortality was similar to the mortality of unvaccinated, uninfec...
متن کاملMeasles case fatality ratio in India a review of community based studies.
CONTEXT Measles remains a major cause of child mortality in India. Measles case fatality ratios (CFRs) vary substantially between countries and even within the same community over time. We present a review of Indian community-based measles CFR studies conducted from 1975 to 2008. EVIDENCE ACQUISITION PubMed, Cochrane Libraries, and all WHO databases were searched using a combination of terms....
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- American journal of epidemiology
دوره 145 1 شماره
صفحات -
تاریخ انتشار 1997