Measles sero-surveillance during mass immunisation campaign in Malawi.
OBJECTIVE
To determine age-specific measles antibody prevalence and serological response to vaccination during the first mass campaign against measles in Malawi.


METHODS
Cross-sectional study using a questionnaire and a serological particle agglutination (PA) test.


METHODS
Two health centres in Salima district, central Malawi during the national measles immunisation week, 1998.


METHODS
Two hundred forty six under-five year old children.


RESULTS
Seventy four per cent of enrolled children (95% confidence interval, 69-80%) were measles PA antibody positive at the vaccination. The antibody positive rate was 17.4% in children aged 8-12 months and gradually increased up to 90% by four years-old, while the age-specific geometric mean titers (GMTs) in 48-59 months-old group were significantly lower than those in 24-35 months-old group, suggesting antibody waning after previous vaccination (p = 0.0047). Two hundred and thirty follow up specimens were obtained eight weeks after the vaccination. The sero-conversion rate was 100% in 58 children sero-negative at the vaccination and the GMTs in 172 children seropositive at the vaccination were significantly increased (p < 0.001).


CONCLUSIONS
These results indicated that the first national measles immunisation campaign successfully immunised the enrolled children or gave a booster response of antibody levels. It was also confirmed that the PA test was easy to perform and most suitable for the field condition in developing countries.
Takechi
M
M
Community Health Sciences Unit, Ministry of Health and Population, Private Bag 65, Lilongwe, Malawi.
Matsuo
M
M
Butao
D
D
Zungu
I L
IL
Chakanika
I
I
Michongwe
J
J
D000293:Adolescent; D000914:Antibodies, Viral / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D003906:Developing Countries; D005260:Female; D006801:Humans; D007109:Immunity / Q000502:physiology; D017589:Immunization Programs / Q000458:organization & administration*; D007115:Immunization Schedule; D007223:Infant; D008295:Malawi; D008297:Male; D032541:Mass Vaccination; D008457:Measles / Q000276:immunology* / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage*; D011336:Probability; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D011795:Surveys and Questionnaires
D000914:Antibodies, Viral; D008458:Measles Vaccine