Cohort effects in dynamic models and their impact on vaccination programmes: an example from Hepatitis A
2006

Impact of Cohort Effects on Hepatitis A Vaccination Models

publication Evidence: high

Author Information

Author(s): Srinivasa Rao Arni, Maggie H Chen, Ba' Z Pham, Andrea C Tricco, Vladimir Gilca, Bernard Duval, Murray D Krahn, Chris T Bauch

Primary Institution: Department of Mathematics and Statistics, University of Guelph

Hypothesis

How do cohort effects influence the predictions of vaccination impact for Hepatitis A?

Conclusion

Including cohort effects in dynamic models significantly alters the predicted impact of vaccination on incidence and mortality.

Supporting Evidence

  • Hepatitis A transmissibility has declined by a factor of 2.8 since the early twentieth century.
  • Failure to include cohort effects leads to significant over-predictions of incidence and mortality.
  • The percentage reduction in incidence and mortality due to vaccination is over-predicted when cohort effects are not included.

Takeaway

When we look at how many people get sick from Hepatitis A, we need to remember that older people got sick more in the past than younger people do now, which changes how we think about vaccines.

Methodology

An age-structured compartmental model was developed to analyze Hepatitis A transmission and vaccination effects in Canada.

Potential Biases

Potential bias from using seroprevalence data in multiple ways during parameterization.

Limitations

The model may not account for all heterogeneities in transmission and relies on historical data that may not reflect current conditions.

Participant Demographics

Canadian-born individuals of various age classes.

Digital Object Identifier (DOI)

10.1186/1471-2334-6-174

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