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Efficacy of Haemophilus influenzae type b conjugate vaccine PRP-T
R Booy1, S Hodgson, L Carpenter
1Department of Paediatrics, Oxford Radcliffe Hospital, Headington, UK.
Insights
The Haemophilus influenzae type b (Hib) conjugate vaccine PRP-T demonstrated 100% efficacy in a UK study. This vaccine provides high protection for infants on an accelerated schedule without a booster dose.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Haemophilus influenzae type b (Hib) infections pose a significant risk to infants.
- The development of conjugate vaccines like PRP-T is crucial for preventing Hib disease.
Purpose of the Study:
- To evaluate the efficacy of the Haemophilus influenzae type b (Hib) conjugate vaccine PRP-T.
- To assess the effectiveness of an accelerated immunization schedule for PRP-T.
- To determine the duration of protection offered by PRP-T without a booster dose.
Main Methods:
- A controlled community intervention study was conducted in the Oxford region, UK.
- Infants received PRP-T vaccine via separate injection alongside standard diphtheria, tetanus, and pertussis vaccines.
- An accelerated 2, 3, and 4 month schedule was implemented without a second-year booster dose.
Main Results:
- Vaccine efficacy against Hib infection was 100% (95% CI 80-100%) among infants receiving three doses.
- Intention-to-treat analysis indicated a high vaccine efficacy of 90% (95% CI 50-99%).
- Follow-up until November 1993 revealed only one vaccine failure in an infant and no invasive infections in children over one year old.
Conclusions:
- The PRP-T vaccine exhibits high protective efficacy when administered using an accelerated immunization schedule.
- PRP-T appears to provide sustained protection through the second year of life without the need for a booster dose.
- These findings support the use of PRP-T in the Expanded Programme of Immunisation for Hib prevention.
Abstract:
Efficacy of the Haemophilus influenzae type b (Hib) conjugate vaccine PRP-T (Pasteur-Merieux) was evaluated in a controlled community intervention study in the Oxford region, UK. PRP-T was offered to infants from May 1, 1991 in three of the region's eight districts and from July 1, 1991, in a fourth district. It was given by separate injection in addition to the standard diphtheria, tetanus, and pertussis vaccine according to an accelerated 2, 3, and 4 month schedule without a booster dose in the second year of life. By October 1, 1992, more than 90% of infants in vaccine districts had received at least one dose of PRP-T. None of the infants given three doses had developed Hib infection, whereas 11 infections occurred in the control population (vaccine efficacy 100%, 95% CI 80-100%). Intention-to-treat analysis also showed a high estimate of efficacy for the vaccine (90%, 50-99%). Follow-up of study children until November 1, 1993, has shown only 1 vaccine failure in an infant, and no invasive infections in those older than 1 year (average age 22 months). PRP-T vaccine had high protective efficacy with an accelerated immunisation schedule. Furthermore, the vaccine appears to remain protective through the second year of life without a booster dose. These findings provide encouragement for use of PRP-T in the Expanded Programme of Immunisation.