In 2020, the World Health Organization introduced a plan to eliminate cervical cancer as a public health threat by 2030. A first step towards this goal is for her to have 90% of girls fully vaccinated against human papillomavirus (HPV) by the age of 15. Her gynecologic oncologist, Lynette Denny, details how much progress is still needed and what hurdles need to be overcome.
How big is the threat of cervical cancer in sub-Saharan Africa?
Cervical cancer is one of the most common cancers in women. Sub-Saharan Africa has the highest number of cervical cancer diagnoses in the world. Mortality from cervical cancer in the region is three times her global average. The burden of HIV in sub-Saharan Africa contributes to inequality. In 2021, 63.8% of women with cervical cancer in Southern Africa were living with HIV, as were 27.4% of women in East Africa.
Most cases of cervical cancer are caused by the human papillomavirus (HPV), which is transmitted through skin-to-skin contact, including sexual contact.
How do countries compare in meeting WHO’s goals?
By June 2020, more than half of WHO Member States (107 out of 194) had introduced HPV vaccination nationally or partially.
The numbers show that there are significant differences in coverage by geographic region. High-income countries such as Australia and New Zealand have the highest HPV vaccination coverage at 77%. Low- and middle-income countries lag far behind, with only 41% having introduced HPV vaccination by the end of 2019. In sub-Saharan Africa, only 20% of the target population is vaccinated.
The level of vaccination is important because it is theoretically possible to eliminate HPV as a human pathogen over time by broadly covering the appropriate age group. This was the case with smallpox.
Most low- and middle-income countries (90%) provide vaccination through school and institutional vaccination. A two-dose schedule is the most common. When the HPV vaccine was first approved for use, a 13-year-old girl from age 9 was given three doses. First she doses one. 1-2 months after the first dose she gives her 2 doses. The third dose will be given after she is 6 months old.
It was later found that two doses conferred the same level of immunity as three doses.
It is now recognized that one dose is as effective as three doses in preventing HPV infection in the general population. In April 2022, the WHO Strategic Advisory Group of Experts on Immunization concluded that a single dose of his HPV vaccine would provide “his robust protection against HPV comparable to a two-dose schedule”. . However, due to limited evidence, people living with HIV should continue to receive 3 doses if possible, otherwise he recommends at least 2 doses.
Fewer doses has important implications for cost and logistics. A single dose could be a game-changer in expanding coverage for eligible girls. It increased to 26% in 2018 and 2019. Comparable dropout rates in high-income countries average 11%.
In 2019, 33 of the 107 HPV vaccination programs were gender neutral, with both girls and boys vaccinated. Vaccinating both boys and girls increases immunity known as herd immunity. In other words, it reduces the prevalence of HPV in the population. Additionally, the boy is protected from her HPV-related anal, penile, and oropharyngeal cancers. However, including boys in immunization programs when most girls are not immunized is not cost-effective.
Globally, it is estimated that 15% of girls and 4% of boys were vaccinated in 2019.
What is the surest way to meet the WHO’s goals?
There are many important steps.
An important starting point is to gain political support for HPV vaccination. A high level of cooperation is needed between ministries of health, ministries of education, ministries of social development and existing immunization programmes.
The most successful programs use school-based facilities for vaccination. However, this excludes adolescents not participating in the school system, so facility-based programs must be created.
Extensive information and public education are important. Educational campaigns should include parents, the general public, teachers and health workers.
Adequate supply of vaccines is critical and vaccine administration infrastructure must be robust. All logistics of vaccine introduction, including distribution, cold chain management, waste management, and clinical care, need attention. Appropriate statistics and information should be maintained and monitored on a regular basis.
Anti-vaccination programs need to be monitored, and their allegations must be dealt with swiftly and with cultural sensitivity.
What is Holdup?
COVID has had a major impact on many HPV vaccination programs. Low- and middle-income countries were hit particularly hard. As an example, South Africa’s program coverage has decreased from 85% when it was introduced in 2014 to 3% in 2020. The program is still trying to recover.
In addition to the impact of COVID on immunization practices, recommendations to include boys and older women in immunization programs have resulted in a global shortage of the HPV vaccine. The shortfall was he recognized in 2020 and was projected to last three to five years. A statement issued by the International Society of Papillomaviruses recommends a temporary cessation of gender-neutral vaccination and vaccination of older women. And while supplies are constrained, HPV vaccination should be limited to girls from her 9 years old to her 14 years old.
What should countries focus on?
HPV vaccines currently available on the market are prophylactic. It protects people who have never been exposed to HPV infection and prevents her from 70% to 90% of all cervical cancers. (No vaccine is 100% effective.)
For the past 30 years, I have been researching safe, viable and effective alternatives to Pap smears to prevent cervical cancer. When I started in 1995, the HPV vaccine had not yet been made. With its advent, the possibility of ending cancers associated with HPV infection became a reality.
Who gets the vaccine depends on age, gender and resources. Preference should be given to girls aged 9-14. As resources increase, girls aged 15-18 should be included. Then you need to include women aged 19-26. Boys should not be vaccinated until at least 90% coverage has been achieved in girls aged 9 to 14 years.
Most vaccinated older women may have already been exposed to HPV infection (even if the infection has since cleared) and are in well-resourced settings where widespread vaccination coverage has been achieved. must be reserved for
Vaccinating boys has many benefits. In particular, it helps prevent HPV-related cancers in men and men who have sex with men, and increases herd immunity. However, expanding the program to include men may affect resource distribution and exclusion of other vulnerable groups.
This article is reprinted from The Conversation, a non-profit news site dedicated to sharing ideas from academic experts. The Conversation has a variety of engaging free newsletters.
Author: Lynette Denny University of Cape Town.
Lynette Denny is funded by the National Institutes of Health.