Substantial increases in cervical cancer inequalities worldwide without enhanced human papillomavirus vaccination and...

To reduce worldwide inequalities, WHO made a call for action to eliminate cervical cancer by vaccinating 90% of girls, screening 70% of women, and treating 90% of pre-cancers and cancers. Low-income countries and lower-middle-income countries (LMICs) are far from reaching the WHO elimination targets compared with high-income countries (HICs). Using mathematical modelling, we aimed to examine the following questions: (1) Are we on the path to cervical cancer elimination in LMICs and HICs? (2) What is the potential evolution of inequalities in cervical cancer between LMICs and HICs under current screening and vaccination coverage? And (3) what would be the potential impact of enhanced prevention strategies (ie, human papillomavirus [HPV] vaccination and screening) on inequalities and cervical cancer elimination?

We used the HPV-ADVISE model to project the age-standardised cervical cancer incidence in 67 LMICs and 42 HICs for different HPV vaccination and screening scenarios. For the status quo scenario (of HPV vaccination and screening), we modelled the vaccine used, the start year of vaccination, vaccination coverage, and the target population for each country, and current screening coverage in LMICs and HICs. We examined five enhanced prevention strategies for LMICs: (1) status quo for all countries using the nine-valent vaccine; (2) reaching 90% vaccination coverage for girls-only routine vaccination; (3) reaching the WHO vaccination, screening, and treatment elimination targets; (4) adding routine vaccination for boys with 90% coverage (ie, universal routine vaccination) and multi-age-cohort vaccination; and (5) reaching the WHO elimination targets combined with universal routine and multi-age-cohort vaccination. Inequalities were measured as the age-standardised cervical cancer incidence (ASR) ratio between LMICs and HICs (RR_LMIC/HIC=ASR_LMICs/ASR_HICs).

Under the status quo, the model projected that cervical cancer incidence in LMICs would decrease by only 23% while HICs would reach elimination by 2048 (age-standardised cervical cancer incidence LMIC/HIC=3 in 2022 and 12 in 2105). Reaching 90% vaccination coverage among girls in LMICs would reduce these inequalities (RR_LMIC/HIC=2 in 2105) and lead to elimination in LMICs outside sub-Saharan Africa. To reach equality between LMICs and HICs and elimination in all LMIC regions, LMICs would need to reach the WHO elimination targets and introduce universal vaccination and multi-age-cohort vaccination.

Worldwide inequalities in cervical cancer have been projected to increase dramatically without enhanced HPV prevention strategies. Reaching WHO vaccination and screening elimination targets or introducing universal vaccination with high coverage is necessary to eliminate cervical cancer in LMICs, which would substantially attenuate worldwide inequalities.

Canada Research Chairs Program, Canadian Institute of Health Research, and Fonds de recherche du Québec through the research centre grant for the CHU de Québec-Université Laval Research Center.