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Measles control in Yaounde: justification of a one dose, nine month minimum age vaccination policy in tropical Africa

D L Heymann, G K Mayben, K R Murphy

    Lancet (London, England)
    |December 24, 1983
    PubMed

    Insights

    In tropical Africa, increasing the minimum measles vaccination age to 9 months effectively reduced measles cases. This policy change led to significant decreases in measles incidence, even in infants under 9 months old.

    Area of Science:

    • Public Health
    • Vaccinology
    • Epidemiology

    Background:

    • The World Health Organization (WHO) recommends a single measles vaccine dose at a minimum age of 9 months for tropical countries.
    • Some African nations report a significant burden of measles in infants younger than 9 months, leading to reluctance in adopting the WHO recommendation.
    • Cameroon's Ministry of Health adjusted its measles control strategy in 1974, raising the minimum vaccination age from 6 to 9 months.

    Purpose of the Study:

    • To evaluate the impact of increasing the minimum measles vaccination age to 9 months in Cameroon.
    • To assess measles incidence and attack rates following the policy change.

    Main Methods:

    • Post-implementation surveillance of measles cases in Yaounde, Cameroon, over a five-year period.
    • Analysis of measles incidence and attack rates among different age groups, particularly those under 9 months.
    • Assessment of vaccination coverage rates among children aged 12-23 months.

    Main Results:

    • No need to revert to the previous minimum vaccination age of 6 months was identified.
    • By 1979, measles vaccination coverage among children aged 12-23 months reached 40%.
    • A 44% decrease in reported measles cases across all ages was observed.
    • A significant 64% reduction in the measles attack rate was noted among children under 9 months of age.

    Conclusions:

    • The findings support the one-dose, 9-month minimum age measles vaccination policy for tropical Africa.
    • The policy change demonstrated effectiveness in reducing measles burden, including in the vulnerable under-9-month age group.
    • Continued surveillance confirmed the viability and success of the adjusted vaccination strategy.

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