Human papillomavirus (HPV) is the most common sexually transmitted infection worldwide and affects both sexually active men and women. Although HPV infection is often harmless, long-lasting infection can lead to a variety of life-threatening cancers. Each year, HPV is estimated to cause more than 630,000 new cancer cases and 311,000 deaths globally [1]. The vast majority of the cancers caused by HPV –530,000–are cervical cancers, but HPV strains have also been associated with cancers of the vulva, vagina, anus, penis, and oropharynx [1].
HPV continues to present as a major threat to women’s health as it is the primary cause of cervical cancer, ranking as the fourth most common cancer among women worldwide [2]. However, over 85% of the global burden of HPV-related cervical cancers falls disproportionately among women in low and middle-income countries [2]. In most sub-Saharan regions in Africa, cervical cancer is the most leading cause of cancer deaths among women, leading to nearly 112,000 cases of cancer and over 76,000 deaths each year [3]. In Bolivia, cervical cancer is the leading cause of female cancer cases and deaths and faces nearly 2,000 new cases and over 1,000 deaths annually [4]. As low- and middle-income countries (LMICs) face severely limited access to prevention, screening, and treatment services, more women are dying of cervical cancer than are dying in childbirth [5]. HPV is preventable through effective screening and vaccination measures. To combat cervical cancer, it is essential to advocate for building and supporting optimized local programs, guiding rapid country adoption of revisions in vaccine schedule recommendations, and accelerating HPV vaccine introduction.
To date, three safe and efficacious HPV vaccines have been prequalified by the World Health Organization. These vaccines protect against more than 70% of cancer-causing HPV infections, making HPV vaccination the most cost-effective intervention for the prevention of cervical cancer [2]. A study published in the Lancet in 2020 predicted that vaccination against HPV in girls ages 9-14 years could avert 61 million cases of cervical cancer in the next century [6], suggesting that high HPV vaccination coverage among girls can lead to the elimination of cervical cancer in most LMICs. In 2020, the WHO (World Health Organization) launched a global strategy to eliminate cervical cancer by 2030 [7]. Achieving this goal rests on their 90-70-90 targets, consisting of:
- 90% of girls fully vaccinated with the HPV vaccine by the age of 15
- 70% of women screened using a high-performance test by the age of 35, and again by the age of 45
- 90% of women with pre-cancer treated and 90% of women with invasive cancer managed
Despite the proven safety, efficacy, and cost-effectiveness of HPV vaccines, there are significant barriers in global implementation and coverage remains suboptimal. Several LMICs face health system barriers in human resources and limited sustainable financing that compromise the ability to effectively implement HPV vaccine programs. Although Gavi, the Vaccine Alliance has provided funding to support national programs for HPV vaccination, many LMICs still do not qualify for Gavi support. Currently, less than 30% of LMICs have introduced HPV vaccination compared to more than 85% of high-income countries [6].
The increasing health system strain imposed by COVID-19 creates challenges in improving HPV vaccine supply and uptake. Stay-at-home orders and social distancing measures have led to the suspension of immunization activities in various countries and increased the risk of under-immunization in low-resource settings. In countries that have introduced the HPV vaccine, the pandemic resulted in 1.6 million girls unable to be vaccinated [8]. Furthermore, only 13% of girls were vaccinated against HPV worldwide, declining from 15% in 2019 [8].
Citations
- de Martel C, Plummer M, Vignat J, Franceschi S. Worldwide burden of cancer attributable to HPV by site, country and HPV type. Int J Cancer. 2017 Aug 15;141(4):664–70.
- Human papillomavirus (HPV) and cervical cancer [Internet]. [cited 2021 Aug 3]. Available from: https://www.who.int/news-room/fact-sheets/detail/human-papillomavirus-(hpv)-and-cervical-cancer
- Sub-Saharan Africa [Internet]. The Cancer Atlas. [cited 2021 Aug 3]. Available from: http://canceratlas.cancer.org/n6X
- HPV INFORMATION CENTRE [Internet]. [cited 2021 Aug 3]. Available from: https://hpvcentre.net/datastatistics.php
- Aylward J. Global burden of cervical cancer – TogetHER for Health [Internet]. https://togetherforhealth.org/. [cited 2021 Aug 3]. Available from: https://togetherforhealth.org/global-burden-cervical-cancer/
- Brisson M, Kim JJ, Canfell K, Drolet M, Gingras G, Burger EA, et al. Impact of HPV vaccination and cervical screening on cervical cancer elimination: a comparative modelling analysis in 78 low-income and lower-middle-income countries. Lancet. 2020 Feb 22;395(10224):575–90.
- Cervical cancer elimination initiative [Internet]. [cited 2021 Aug 3]. Available from: https://www.who.int/initiatives/cervical-cancer-elimination-initiative