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Enterovirus survey before and after poliomyelitis vaccination in Kuala Lumpur, Malaysia
Insights
Enteroviruses, including polioviruses, were studied in children before and after a polio vaccination campaign. While a temporary drop occurred, enterovirus prevalence returned to pre-vaccination levels within years.
Area of Science:
- Virology
- Public Health
- Pediatrics
Background:
- Enteroviruses are common viral infections in children.
- A polio type 1 epidemic prompted mass vaccination efforts in Kuala Lumpur in October 1971.
- Understanding enterovirus circulation dynamics is crucial for public health interventions.
Purpose of the Study:
- To isolate and identify enteroviruses in healthy children before and after a mass polio vaccination campaign.
- To assess the impact of the vaccination campaign on enterovirus prevalence.
- To identify the predominant enterovirus types and age groups affected.
Main Methods:
- Stool samples were collected from healthy children aged 0-7 years in Kuala Lumpur.
- Samples were collected before and after a mass polio vaccination campaign.
- Enteroviruses were isolated and characterized, with a focus on polioviruses and non-polio enteroviruses.
Main Results:
- The overall enterovirus prevalence was 11.9% before vaccination (3.0% polioviruses, 8.9% non-polio enteroviruses) and remained similar after.
- Coxsackie A viruses were the most prevalent non-polio enteroviruses.
- Children aged 0-2 years showed the highest isolation rates.
- A temporary decrease in enteroviruses and polioviruses was observed post-vaccination, but rates returned to baseline levels in subsequent years.
Conclusions:
- Mass polio vaccination had a transient impact on overall enterovirus prevalence.
- Non-polio enteroviruses, particularly Coxsackie A, remained prevalent in young children.
- Enterovirus surveillance is essential to monitor viral circulation patterns and vaccine effectiveness.
Abstract:
Stool samples from healthy children mainly of the low income group aged 0 to 7 years of age from five Maternal and Child Health Centres in Kuala Lumpur were obtained for isolation of enteroviruses. The specimens were collected before and after the mass vaccination given in the face of polio type 1 epidemic which started in October, 1971. The prevelance rate of enteroviruses was 11.9% (3.0% polioviruses, 8.9% non-polio enteroviruses) before the vaccination and essentially the same after. Coxsackie A viruses predominated over the other enteroviruses in the pre- and post-vaccination phases. The highest isolation rate of enteroviruses was observed in children 0 to 2 years age. No significant differences in distribution by sex, race and month were noted. A sharp fall in the prevalence rates of total enteroviruses and polioviruses was noted shortly after the mass vaccination campaign However, the rates reverted to the pre-vaccination state during the next successive years.