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b-CAPSA I Haemophilus influenzae, type b, capsular polysaccharide vaccine safety
Insights
The b-CAPSA I vaccine for Haemophilus influenzae type b showed mild side effects in children. Most adverse events were local reactions, with rare instances of wheezing or seizures possibly linked to the vaccine.
Area of Science:
- Pediatric Vaccinology
- Public Health Surveillance
- Immunology
Background:
- Haemophilus influenzae type b (Hib) infections pose a significant risk to young children.
- Effective vaccines are crucial for preventing Hib disease and its complications.
- The b-CAPSA I vaccine was developed to provide protection against Hib.
Purpose of the Study:
- To evaluate the safety and adverse effects of the b-CAPSA I capsular polysaccharide vaccine.
- To assess immediate and short-term side effects following Hib vaccination in a large pediatric cohort.
Main Methods:
- A large-scale study involving 87,541 children aged 2-5 years vaccinated with b-CAPSA I.
- Multi-modal surveillance including 24-hour recall questionnaires for immediate side effects.
- 30-day follow-up questionnaires and active surveillance of healthcare utilization for adverse events.
Main Results:
- Local reactions (erythema, swelling, tenderness) and mild temperature elevation were uncommon.
- Two cases of wheezing occurred shortly after immunization, with one hospitalization possibly vaccine-associated.
- Three seizures were reported within 30 days, none deemed vaccine-related by physicians.
Conclusions:
- The b-CAPSA I vaccine demonstrated a favorable safety profile in young children.
- Adverse effects were predominantly mild and localized.
- Rare occurrences of bronchospasm were observed, warranting continued monitoring.
Abstract:
The b-CAPSA I capsular polysaccharide vaccine for Haemophilus influenzae type b was given to 87,541 children 2 through 5 years of age in the Kaiser Permanente Medical Care Program, and the children were then followed using a multiple modality surveillance. Phase 1 consisted of 24-hour recall of immediate side effects which were recorded on questionnaires given to families of 13,500 children. Local side effects were found to be uncommon: 2.3% had a temperature of greater than or equal to 38.3 degrees C (greater than or equal to 101 degrees F); 4.8% had local erythema, 2.9% local swelling, and 12.6% local tenderness; two children had wheezing shortly after immunization. In Phase 2, 30 days after immunization, questionnaires were mailed to parents of all 87,541 children, who were asked to respond to questions about illnesses and health care. Phase 3 consisted of active surveillance of patient health care use by physicians and nurses during the 30 days after immunization. During the 30-day reporting periods, there were 40 hospitalizations, including one for wheezing and one for febrile seizure. Of the 40 hospitalizations, only the one for wheezing was believed by the admitting physician to be probably associated with vaccine administration. Three children had seizures within 30 days of immunization. None of the seizures was believed by the reporting physician to be associated with immunization. Adverse effects of the vaccine were mild, limited to local reactions and occasional temperature elevation; bronchospasm after immunization occurred rarely.