Chathika Weerasuriya 2019

Chathika Weerasuriya

LSHTM, UK

Mathematical modelling of the epidemiological impact, cost-effectiveness and budget impact of novel tuberculosis vaccines on multi-drug resistant tuberculosis

Poster Abstract

Background

The limited resources available for new TB control efforts, coupled with rising MDR-TB burden and costs warrant investigation into the role of vaccination in controlling TB drug resistance. We model the potential impact of novel prophylactic vaccines on MDR-TB burden and identify vaccine characteristics likely to contribute most towards achieving the 2030 UN SDG and 2050 WHO End TB targets.

Methods

We constructed an age-stratified, deterministic, compartmental dynamic transmission model of TB, including treatment history, drug resistance and vaccination strata. We fitted “baseline” (no new vaccine) scenarios, to historic epidemiological and demographic data and projected (MDR-)TB epidemiology until 2050 in China, with and without scaled-up future programmatic MDR-TB management. Into these baseline scenarios, we simulated introducing potential TB vaccines in 2027, with (1) efficacy pre-infection, post-infection or pre- and post-infection, (2) 5 years to lifelong duration of protection, (3) and 30-90% prevention of disease efficacy. We simulated routine vaccination of 9-year olds, with 10-yearly adult/adolescent mass campaigns. We estimated economic costs from a health service perspective to calculate incremental cost-effectiveness ratios as incremental costs per disability-adjusted life year averted.

Results

Vaccination will likely be effective in reducing MDR-TB burden, even alongside scaled-up programmatic management. Such scale up altered the primarily transmission-driven MDR-TB epidemic towards a mixed transmission-reactivation driven epidemic, improving the effectiveness of post-infection vaccines relative to pre-infection vaccines. Analysis of vaccine cost-effectiveness and budget impact in China and a multi-country comparison including India and Russia is underway.

Conclusions

Novel vaccines could contribute to reducing MDR-TB burden by 2030 and 2050. Concurrent changes in programmatic management may alter the preferred characteristics of such vaccines. We present the first dynamic model of TB which includes both vaccines and MDR-TB, whose results are important for informing decisions in vaccine development, and programmatic considerations in efforts to end TB.

Biography

I am a current PhD student at the TB Modelling Group at LSHTM, investigating the epidemiologic and health economic impact of potential novel TB vaccines on MDR-TB. Prior to this, I completed core medical training as a physician in the NHS and undertook a MSc in Public Health (Health Economics) at LSHTM.