The Effect of BCG Vaccine on Morbidity From Malaria
Trial Snapshot
- Phase
- Phase 3
- Status
- Completed
- Enrollment
- 1,200
- Locations
- 1
- Primary Endpoint
- Incidence of clinical malaria.
Study Overview
Brief Summary
BCG vaccine is given at or shortly after birth in many developing countries to prevent tuberculosis. In Guinea Bissau, it has been shown that its protective effect against death is greater than would be expected from its effect against tuberculosis. This observation suggests that BCG may enhance the ability of the immune system of young children to make a protective response to other infections, including malaria. There is some evidence to support this hypothesis as BCG protects against malaria in experimental animals.
Because BCG is a recommended vaccine, a randomised controlled trial of BCG at birth would not be ethically justifiable. However, it is not known whether re-vaccination with BCG in the second year of life might provide some added benefit and a large study to determine this is under way in Guinea Bissau. This study examined the effect of re-vaccination with BCG on the incidence of clinical malaria. If re-vaccination with BCG at 19 months of age is found to protect against malaria this would support the hypothesis that one of the ways that BCG at birth provides protection to young children is through an effect on malaria.
Detailed Description
Background
Studies undertaken in Guinea Bissau have shown that the protective effect of BCG vaccine against death in young children is greater than would be expected from its effect in preventing tuberculosis. How this might be achieved is not known but BCG could act by enhancing the immune response to common infections including malaria which is an important cause of death in young children in Bissau. There is some laboratory evidence to support this hypothesis. BCG prevents malaria in rodents, probably by activating their reticulo-endothelial system and Freund's adjuvant, an emulsion of tubercle bacilli in oil, prevents malaria in primates.
In most developing countries, BCG is given as soon as possible after birth and is an integral part of the immunisation programme so that a controlled trial which withheld neonatal BCG vaccination would not be ethical. However, it is uncertain how long the non-specific protective effect of BCG persists and whether this could be sustained by a further injection of BCG in the second year of life. A major trial to investigate this possibility is under way in Guinea Bissau with mortality as its main end-point. The current study has made use of this opportunity to investigate whether or not re-vaccination with BCG has a protective effect against malaria.
Objective
The primary objective of the study was to determine if re-vaccination with BCG reduced morbidity from malaria in young children.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Single Group
- Primary Purpose
- Prevention
- Masking
- Single
Eligibility Criteria
- Ages
- 18 Months to 24 Months (Child)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Age more than 18 months and less than 24 months
- •Previous BCG vaccination
Exclusion Criteria
- •Mantoux skin reaction > 14 mm
- •Chronic underlying illness
Outcomes
Primary Outcomes
Incidence of clinical malaria.
Secondary Outcomes
- Prevalence of malaria parasitemia.