WHO releases recommendations regarding HPV vaccination as primary preventive intervention against cervical cancer.
The World Health Organization (WHO) recently released a Position Paper regarding recommendations for vaccination against the most common sexually transmitted infection in the United States: human papillomavirus (HPV).
Because HPV-related diseases, such as cervical cancer, are a global health concern, WHO recommends that HPV vaccines should be “included in national immunization programs.” Cervical cancer accounts for a staggering majority (84%) of HPV-associated cancers, and therefore, “should remain the priority for HPV immunization,” the authors write. The best way to prevent cervical cancer? Immunizing girls before they are sexually active. All of the available HPV vaccines—the bivalent, quadrivalent, and nonavalent—are all “excellent” when it comes to “safety, efficacy, and effectiveness profiles.”
WHO recommends that HPV vaccines should be incorporated into a “coordinated and comprehensive strategy.” In the paper, the authors note that this strategy will include the following components:
Although vaccination will serve as a “primary preventive intervention,” authors note that, later on in their lives, individuals will still need to go for screening, “since the existing vaccines do not protect against all high-risk HPV types and will have limited impact on disease in women older than the vaccine eligible group(s).” WHO also suggests linking HPV vaccination with other vaccinations typically administered at the same age (such as tetanus). The authors also recommend incorporating vaccination into programs that are specifically targeting younger individuals. On a global scale, WHO calls for “all countries to proceed with nationwide introduction of HPV vaccination.” In the paper, study authors write that countries should use approaches that are:
The primary population target for HPV vaccination is girls between the age of 9 and 14, who are not yet sexually active. In fact, authors write that “Vaccination strategies should initially prioritize high coverage in this priority population.” The secondary population target? Females over 15 years of age, or males. WHO recommends that this population receive vaccination only when “feasible, affordable, [and] cost-effective,” and, if it doesn’t avert resources away from targeting the primary population. Furthermore, WHO recommends a vaccination strategy that targets “multiple age cohorts of girls aged between 9 and 18 years.” They feel that this “would result in faster and greater population impact than vaccination of single age cohorts, due to the estimated increase in direct protection and herd immunity.”
WHO reports that all 3 vaccines—bivalent, quadrivalent, and nonavalent—are “comparable” when it comes to “immunogenicity, efficacy, and effectiveness” in cervical cancer prevention. When it comes to choosing which vaccine to use, WHO suggests taking “locally relevant data” into consideration as well as factors such as “the scale of the prevailing HPV-associated public health problem” and the “population for which the vaccine has been approved.” The cost and nature of the vaccination program should also be considered.
A 2-dose schedule—with 6 months in between doses—is recommended for those who are receiving their first dose of the vaccine before 15 years of age. However, a 2-dose schedule is also acceptable for those who are over 15 years of age at the time of the second dose. WHO recommends a 3-dose schedule—to be taken at 0, 1, 2, 6 months—for all individuals over 15 years of age receiving their first dose; this dosing schedule is also recommended for those who are under the age of 15, who are HIV-infected or are otherwise immunocompromised.
For the most part, adverse events associated with HPV vaccination are “non-serious and of a short duration.” HPV vaccination is safe in those who are immunocompromised or HIV-infected, authors write. WHO recommends that pregnant women not be vaccinated, as there is limited data available regarding how safe immunization is in this population.
WHO recommends “monitoring prevalence of infection by HPV type among sexually active young women,” as they feel that it could “provide an early indication of vaccine effectiveness.” However, the authors note that doing this effectively would require “considerable commitment of resources for at least 5-10 years,” and thus, might not be an appropriate strategy for all countries. They do recommend that healthcare officials from all countries work on reporting to comprehensive cancer registries, as these registries “are needed to measure the impact of HPV vaccine programs and of cervical cancer screening.”
Lastly, WHO is calling for more research regarding HPV vaccination. The authors write, “Further research is needed to generate data on the longer-term clinical effectiveness and duration of protection, particularly for the nonavalent HPV vaccine, after 2-dose and 3-dose schedules.” They also call for more multicenter studies (on healthy young women as well as those who are infected with HIV, who are malnourished, or are exposed to malaria) within low-income countries to gage how vaccination impacts these populations.
“Further evidence is required on the effectiveness and cost-effectiveness of a 1-dose schedule, and on the immunogenicity and safety of administering HPV vaccine to children less than 9 years of age,” they added.