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Convulsions following oral polio immunisation
Abstract:
Since the introduction of oral polio vaccine in 1962, 30 cases of convulsions were registered within 30 days after the immunisation in Hamburg. 29 further cases from the surroundings came also to our attention. The majority of these cases occurred within 8 days after the vaccination (44 cases), afterwards only single cases were recorded. 33 patients were males, 24 females (2 cases sex unknown). The majority of the patients had the postvaccinal convulsions between 7 to 36 months of age, a characteristic period for febrile convulsions. 28 patients showed a course typical for febrile convulsions. In some cases intercurrent infections (pneumonia, otitis media purulenta) could also explain the nerval reactions. In 11 cases encephalopathy or encephalitis (1 case due to mumps) had been diagnoses. 8 patients suffered later from a convulsive disorder. Between 1964 and 1974 165,000 children born in Hamburg, were immunised thrice with OPV. In this period 19 convulsions and 3 permanent convulsive disorders were observed (1 case per 8,600 vaccinees; 1 convulsive disorder per 55,000 vaccinees).
Insights
Oral polio vaccine (OPV) is associated with a small number of post-vaccination convulsions, particularly in young children. Long-term risks of convulsive disorders following OPV are rare, suggesting a favorable safety profile.
Area of Science:
- Pediatrics
- Neurology
- Immunology
Background:
- The oral polio vaccine (OPV) has been instrumental in polio eradication efforts since its introduction in 1962.
- Post-vaccination adverse events, including neurological complications, require careful monitoring and analysis.
Purpose of the Study:
- To investigate the incidence and characteristics of convulsions following oral polio vaccination in Hamburg and surrounding areas.
- To assess the long-term risk of convulsive disorders after OPV administration.
Main Methods:
- Retrospective analysis of registered cases of convulsions within 30 days of OPV administration.
- Review of medical records to determine patient demographics, age at vaccination, clinical presentation, and outcomes.
- Calculation of incidence rates for convulsions and persistent convulsive disorders.
Main Results:
- 30 cases of convulsions were registered in Hamburg within 30 days of OPV, with an additional 29 cases from surrounding areas.
- The majority of convulsions occurred within 8 days post-vaccination, primarily in children aged 7-36 months.
- 11 cases involved encephalopathy or encephalitis, and 8 patients later developed a convulsive disorder.
- Between 1964-1974, 19 convulsions and 3 permanent convulsive disorders were observed in 165,000 children, translating to rates of 1:8,600 and 1:55,000, respectively.
Conclusions:
- While OPV can be associated with post-vaccination convulsions, the majority are benign and resemble febrile seizures.
- The risk of developing a permanent convulsive disorder after OPV is very low, supporting its continued use in vaccination programs.