Health gains and financial protection from human papillomavirus vaccination in Ethiopia: findings from a modelling study

Inclusion of marginalized populations in HPV vaccine modeling: A systematic review

OBJECTIVE

Models simulating the potential impacts of Human Papillomavirus (HPV) vaccine have been used globally to guide vaccination policies and programs. We sought to understand how and why marginalized populations have been incorporated into HPV vaccine simulation models.

METHODS

We conducted a systematic search of PubMed, CINAHL, Scopus, and Embase to identify studies using simulation models of HPV vaccination incorporating one or more marginalized population through stratification or subgroup analysis. We extracted data on study characteristics and described these overall and by included marginalized groups.

RESULTS

We identified 36 studies that met inclusion criteria, which modeled vaccination in 21 countries. Models included men who have sex with men (MSM; k = 16), stratification by HIV status (k = 9), race/ethnicity (k = 6), poverty (k = 5), rurality (k = 4), and female sex workers (k = 1). When evaluating for a marginalized group (k = 10), HPV vaccination was generally found to be cost-effective, including for MSM, individuals living with HIV, and rural populations. In studies evaluating equity in cancer prevention (k = 9), HPV vaccination generally advanced equity, but this was sensitive to differences in HPV vaccine uptake and use of absolute or relative measures of inequities. Only one study assessed the impact of an intervention promoting HPV vaccine uptake.

DISCUSSION

Incorporating marginalized populations into decision models can provide valuable insights to guide decision making and improve equity in cancer prevention. More research is needed to understand the equity impact of HPV vaccination on cancer outcomes among marginalized groups. Research should emphasize implementation - including identifying and evaluating specific interventions to increase HPV vaccine uptake.

Equity-Informative Economic Evaluations of Vaccines: A Systematic Literature Review

The Immunization Agenda 2030 prioritizes the populations without access to vaccines. Health equity has been increasingly incorporated into economic evaluations of vaccines to foster equitable access. Robust and standardized methods are needed to evaluate the health equity impact of vaccination programs to ensure monitoring and effective addressing of inequities. However, methods currently in place vary and potentially affect the application of findings to inform policy decision-making. We performed a systematic review by searching PubMed, Embase, Econlit, and the CEA Registry up to 15 December 2022 to identify equity-informative economic evaluations of vaccines. Twenty-one studies were included that performed health equity impact analysis to estimate the distributional impact of vaccines, such as deaths averted and financial risk protection, across equity-relevant subgroups. These studies showed that the introduction of vaccines or improved vaccination coverage resulted in fewer deaths and higher financial risk benefits in subpopulations with higher disease burdens and lower vaccination coverage-particularly poorer income groups and those living in rural areas. In conclusion, methods to incorporate equity have been evolving progressively. Vaccination programs can enhance equity if their design and implementation address existing inequities in order to provide equitable vaccination coverage and achieve health equity.

Knowledge and attitude about human papillomavirus vaccine among female high school students at Jimma town, Ethiopia

BACKGROUND

The Human Papilloma Virus (HPV) is the primary causative agent of cervical cancer. HPV vaccination against human papillomavirus is more effective against cervical cancer. Therefore, this study aimed to investigate the knowledge and attitudes toward the human papillomavirus vaccines among female high-school students.

METHODOLOGY

This cross-sectional study was conducted among female high-school students in Jimma town, Ethiopia. Study participants were selected using a simple random sampling method. Self-administered interviews were conducted using a structured questionnaire. Data were entered using Epi-data version 3.5, exported and analyzed using the statistical package for the social sciences (SPSS) version 21. The Chi-squared (χ2) test was performed to determine the statistical significance between the outcome variable and independent variables.

RESULTS

A total of 366 students participated in this study with a response rate of 94.8%. Only half (52.7%) and nearly one-third (31.4%) of the respondents had good knowledge and positive attitudes toward HPV vaccination, respectively. The predictors that included parents' educational status (χ2 = 1.479, P = .003), students participating in school mini-media (χ2 = 1.519, P = .036), students who had a smartphone (χ2 = 2.118, P = .008), availability of radio or television (TV) at home (χ2 = 2.163, P = .049), and students who received information from social-media (χ2 = 2.15, P = .025) were significantly associated with knowledge of the HPV vaccine.

CONCLUSION

Overall knowledge and attitude toward HPV vaccination were low. All concerned bodies should work jointly to enhance the knowledge and attitudes of female students toward Human Papilloma Virus vaccination.

Projections of human papillomavirus (HPV) vaccination impact in Ethiopia, India, Nigeria and Pakistan: a comparative modelling study

Introduction

Cervical cancer is the second most common cancer among women in Ethiopia, India, Nigeria and Pakistan. Our study objective was to assess similarities and differences in vaccine-impact projections through comparative modelling analysis by independently estimating the potential health impact of human papillomavirus (HPV) vaccination.

Methods

Using two widely published models (Harvard and Papillomavirus Rapid Interface for Modelling and Economics (PRIME)) to estimate HPV vaccination impact, we simulated a vaccination scenario of 90% annual coverage among 10 cohorts of 9-year-old girls from 2021 to 2030 in Ethiopia, India, Nigeria and Pakistan. We estimated potential health impact in terms of cervical cancer cases, deaths and disability-adjusted life years averted among vaccinated cohorts from the time of vaccination until 2100. We harmonised the two models by standardising input data to comparatively estimate HPV vaccination impact.

Results

Prior to harmonising model assumptions, the range between PRIME and Harvard models for number of cervical cancer cases averted by HPV vaccination was: 262 000 to 2 70 000 in Ethiopia; 1 640 000 to 1 970 000 in India; 330 000 to 3 36 000 in Nigeria and 111 000 to 1 33 000 in Pakistan. When harmonising model assumptions, alignment on HPV type distribution significantly narrowed differences in vaccine-impact estimates.

Conclusion

Despite model differences, the Harvard and PRIME models yielded similar vaccine-impact estimates. The main differences in estimates are due to variation in interpretation around data on cervical cancer attribution to HPV-16/18. As countries make progress towards WHO targets for cervical cancer elimination, continued explorations of underlying differences in model inputs, assumptions and results when examining cervical cancer prevention policy will be critical.