Differences in Hib Strains and Vaccine Failures
Author Information
Author(s): Leo Schouls, Han van der Heide, Sandra Witteveen, Bert Zomer, Arie van der Ende, Marina Burger, Corrie Schot
Primary Institution: National Institute for Public Health and the Environment
Hypothesis
Are there genetic differences in Hib strains that explain the increase in vaccine failures in the Netherlands?
Conclusion
Type II strains were only found in non-vaccinated children and produced less capsular polysaccharide than type I strains, which may explain their rapid disappearance after vaccination.
Supporting Evidence
- 5% of strains collected before 1996 were type II.
- Type II strains were not found after 1995.
- Type I strains produced twice as much capsular polysaccharide as type II strains.
Takeaway
There are two types of Hib bacteria, and one type is better at making a protective coating, which helps it survive against vaccines. The less effective type disappeared after the vaccine was introduced.
Methodology
DNA sequencing of capsular gene clusters and PCR analysis of Hib strains collected from patients.
Potential Biases
Potential bias in strain selection and reporting from voluntary submissions to the laboratory.
Limitations
The study only analyzed strains from the Netherlands and may not represent global variations.
Participant Demographics
Strains isolated from Dutch patients with invasive Hib disease, including vaccinated and non-vaccinated children.
Statistical Information
P-Value
p ≤ 0.001
Statistical Significance
p ≤ 0.001
Digital Object Identifier (DOI)
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