Evaluating Vaccine Trials for Intestinal Worms
Author Information
Author(s): Alexander Neal, Bonnie Cundill, Lorenzo Sabatelli, Jeffrey M. Bethony, David Diemert, Peter Hotez, Peter G. Smith, Laura C. Rodrigues, Simon Brooker
Primary Institution: London School of Hygiene and Tropical Medicine
Hypothesis
What are the optimal endpoints and measures of efficacy for vaccine trials against intestinal helminths?
Conclusion
Final mean parasite intensity is a suitable endpoint for later phase vaccine trials, but mass effects of trial interventions are unlikely to significantly reduce the force of infection unless there is high vaccine efficacy and a large proportion of the population enrolled.
Supporting Evidence
- Intestinal helminths infect over one billion people worldwide.
- Current control efforts rely more on chemotherapy than on vaccines.
- The study suggests that measuring mean parasite intensity is a feasible endpoint for vaccine trials.
Takeaway
This study looks at how to measure the effectiveness of vaccines against worms in people, suggesting that counting the average number of worms is a good way to see if the vaccine works.
Methodology
The study uses a modeling approach to assess statistical power based on different efficacy measures and endpoints for vaccine trials.
Potential Biases
Assumptions about the negative binomial distribution parameters may not hold true in all populations.
Limitations
The study assumes no waning of vaccine efficacy and does not account for the time taken for parasites to reach sexual maturity.
Participant Demographics
The study focuses on populations at risk of intestinal helminth infections, particularly in areas with high prevalence.
Statistical Information
Confidence Interval
95% confidence interval for b parameter is 0.6–2.2.
Digital Object Identifier (DOI)
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