Measles vaccine efficacy in Masvingo district, Zimbabwe.

OBJECTIVE

To carry out a survey in Masvingo District to determine the efficacy of measles vaccine.

DESIGN

A retrospective study, using existing health care facility records and interviews with care givers.

SETTING

Using the standard WHO-EPI cluster sampling methodology, 30 clusters were randomly selected in Masvingo District.

SUBJECTS

14 or more children in each of the 30 clusters were selected.

MAIN OUTCOME MEASURES

Occurrence of measles or lack of it among the children aged 12 to 23 months, age at vaccination, status, the age at which the child had measles and availability of a health card.

RESULTS

In Masvingo District from 1987 to 1994, measles incidence remained very high, though mortality drastically declined. Using field survey data measles vaccine efficacy was estimated at 78.3pc (95pc CI 54.1; 89.8). Vaccine coverage was estimated to be 75pc.

CONCLUSION

The efficacy results fall at the lower end, but within the normal limits, of those expected for measles vaccine as used in Zimbabwe. Steps to increase vaccine coverage are of the highest priority.