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Published on: February 23, 2014
Nasopharyngeal colonization: a target for pneumococcal vaccination
Helena Käyhty1, Kari Auranen, Hanna Nohynek
1National Public Health Institute, Department of Vaccines, Helsinki, Finland. helena.kayhty@ktl.fi
Expert Review of Vaccines
|December 22, 2006
Summary
The pneumococcal conjugate vaccine (PCV) prevents disease and spread by reducing nasopharyngeal colonization. Its indirect protection (herd immunity) now prevents more cases than direct vaccination, enhancing cost-effectiveness.
Area of Science:
- Immunology
- Public Health
- Vaccinology
Background:
- Pneumococcal conjugate vaccines (PCV) were licensed in 2000.
- PCV prevents invasive pneumococcal disease and nasopharyngeal colonization.
- Prevention of colonization reduces infection spread and confers herd immunity.
Purpose of the Study:
- To evaluate the indirect protective effects of PCV.
- To assess the impact of PCV on disease prevention beyond direct vaccination.
- To analyze the cost-effectiveness of PCV in light of herd immunity.
Main Methods:
- Analysis of disease incidence data following PCV introduction.
- Evaluation of nasopharyngeal carriage data.
- Assessment of indirect protection and herd immunity effects.
Main Results:
- PCV prevents serious disease and asymptomatic nasopharyngeal colonization.
- Indirect effects (herd immunity) now prevent more cases than direct vaccination.
- Herd immunity is partially offset by serotype replacement with non-vaccine types.
Conclusions:
- PCV's indirect protection significantly enhances its public health impact and cost-effectiveness.
- Increased cost-effectiveness supports PCV use in resource-limited settings.
- Ongoing surveillance for non-vaccine serotype emergence is crucial.
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