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[Measles vaccination and age]
P Aaby1, M Andersen, M Sodemann
1Statens Seruminstitut, København.
Insights
Early measles vaccination (4-8 months) in Guinea-Bissau was linked to lower childhood mortality, contrary to previous findings. This suggests early immunization may be safe and beneficial for child survival.
Area of Science:
- Pediatrics
- Immunology
- Global Health
Background:
- Recent studies suggested high-titre measles vaccine before 9 months may reduce survival.
- This raised concerns about the safety of early infant immunization.
Purpose of the Study:
- To examine the safety and impact of early measles vaccination (Schwarz vaccine) on child mortality in Guinea-Bissau.
- To compare mortality rates between children vaccinated before and after 9 months of age.
Main Methods:
- Retrospective analysis of immunization campaigns in Guinea-Bissau (1980-1983).
- Follow-up of children until age five, death, or migration.
- Comparison of mortality rates based on vaccination age (4-8 months vs. 9-11 months).
Main Results:
- Children vaccinated at 4-8 months showed lower mortality between 9 months and 5 years compared to those vaccinated at 9-11 months.
- Improved survival was independent of better measles protection.
- No socio-cultural differences were found between vaccination groups.
Conclusions:
- Vaccination before 9 months of age appears safe and may reduce overall childhood mortality.
- Findings challenge the current recommended measles immunization strategy in developing countries.
- Randomized trials are recommended to confirm these observations and inform policy.
Abstract:
Recent studies have found administration of high-titre measles vaccine before 9 months of age to be associated with reduced survival. Since this suggests that early immunization could be unsafe, we examined the results of immunization campaigns with Schwarz standard measles vaccine carried out in 1980-1983 in three areas of Guinea-Bissau. Children were followed to death, migration or the age of five years. Children immunized at 4-8 months of age, of whom many were later re-immunized, had lower mortality between nine months and five years of age compared with children vaccinated at 9-11 months of age. The improved survival was unrelated to better protection against measles. There was no sign of socio-cultural differences between children immunized at different ages. Vaccination before 9 months of age is apparently safe and it may reduce childhood mortality compared with the currently recommended strategy of immunizing from nine months of age. Randomized trials are needed to confirm these observations which may have implications for the measles immunization strategy for developing countries.