Challenges in cost-effectiveness analysis modelling of HPV vaccines in LMIC: beyond the Abstract

obinna_e_bips_2Obinna I Ekwunife and Stefan K Lhachimi of EBPH in collaboration with other international researchers – James F. O’Mahony (Ireland), Andreas Gerber Grote (Switzerland), Christoph Mosch (Germany), Tatjana Paeck (Germany) – recently published a systematic review in PharmacoEconomics. The next paragraphs summarize the necessity for the systematic review, the key findings and the recommendations of the authors.

World Health Organization recommended routine HPV vaccination for girls on the condition that vaccination was found to be cost-effective when assessed in the country or region in question [1]. Numerous studies assessing the cost-effectiveness of HPV vaccination have been published for high, middle and low income countries. These studies typically employ decision analytic models as many of the relevant outcomes will occur over periods too long to practically assess within trials. Cost-effectiveness analysis of HPV vaccination for low and middle income countries (LMICs) often use and adapt decision analytic models employed by studies conducted in high income countries.

However, challenges encountered by LMICs in implementing and maintaining a comprehensive cervical cancer prevention strategy make it difficult to anticipate what programme coverage rates and cost of vaccination might be realised. Both are crucial parameters in most decision analytic models of HPV vaccination as they can determine whether vaccination is cost-effective or not. Accordingly, decision analytic models assessing cost-effectiveness of HPV vaccination in LMICs need to account for the distinct challenges that do not apply to high income countries to such an extent if the appropriate policy advice is to be given.

Therefore, the authors conducted a systematic review to assess how context-specific challenges in implementing and maintaining cervical cancer prevention and control strategies in LMICs were accounted for in cost-effectiveness analysis models of human papillomavirus (HPV) vaccination. The review specifically examined the following questions: (1) Does the existing HPV vaccination cost-effectiveness literature acknowledge the particular challenges of LMICs? (2) How were the LMIC-particular challenges accommodated in the models? (3) Is the uncertainty among the parameters that are particularly sensitive to the implementation challenges in LMICs so large that the policy recommendations are affected?

The key findings of the systematic review were that cost per vaccinated girl, vaccine coverage and screening coverage are highly uncertain parameters in model-based cost-effectiveness analysis (CEA) of human papillomavirus (HPV) vaccines in low and middle income countries. These uncertain parameters matter as they can reverse the conclusions regarding cost-effectiveness made by a CEA, thereby altering the resulting policy choice.

The authors’ proposal for refining cost per vaccinated girl estimates for cost-effectiveness analysis model of HPV vaccination in LMICs involves adaptation of HPV vaccine delivery cost from other countries where vaccination has been implemented to the country of study. With regards to vaccination coverage rate, they believe that it will be most appropriate to use previous country-specific vaccine coverage performance as a base case assumption. They propose the use of coverage rates of adolescent catch-up or booster vaccination programme in countries or regions where such programme is in place, such as in the Middle East and North African region [2]. However, in the absence of adolescent vaccination programme, coverage of Diphtheria-Tetanus-Pertusis (DTP3) could serve as a good proxy especially as vaccination coverage with the third dose of DTP vaccines among infants is the main indicator of immunization programmes’ performance and is used as a benchmark to qualify for Vaccine Alliance (Gavi) support [2].   For screening coverage, they recommend the use of cervical cancer screening coverage rate of countries in the same geographical region for analysis assuming an organized national screening or increased future predicted screening. For instance, in the absence of local data African countries could employ the South African screening coverage rate about 20% as the base-case rather than assuming 70% coverage [3].

Futher information

Download the full-text at PharmacoEconomics: Link

References

1. WHO. Human papillomavirus vaccines. WHO position paper. Weekly Epidemiological Record 2009.

2. Jumaan AO, Ghanem S, Taher J, Braikat M, Al Awaidy S, Dbaibo GS. Prospects and challenges in the introduction of human papillomavirus vaccines in the extended Middle East and North Africa region. Vaccine. 2013;31 Suppl 6:G58-64. doi:10.1016/j.vaccine.2012.06.097.

3. Bruni L B-RL, Albero G, Aldea M, Serrano B, Valence S, Brotons M, Mena M, Cosano R, Muñoz J, Bosch FX, de Sanjosé S, Castellsagué X. ICO Information Centre on HPV and Cancer (HPVInformation Centre). Human Papillomavirus and Related Diseases Report: South Africa2015. Report No.: 2015-03-20.

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