Increasing Uptake
The current public health aim is to have 80% of young people in the targeted age group vaccinated with two doses. Today, uptake among those 9-26 years old stands at about 78% of girls and 75% of boys for the first dose, said Annunziata. “But it’s only about 61% for the two doses in the current series, and we want to improve that.”
Some parents may still harbor fears that immunizing teens and tweens — both the American Academy of Pediatrics and the American Cancer Society recommend immunization at age 9 — will open the door to precocious sexual activity.
“But overall, uptake in tweens and young teens has increased because the messaging has changed,” said Myers, with the rationale now focusing on cancer prevention not sexual-infection prophylaxis. “This is similar to the hepatitis B vaccine, which used to be given to young adults and is now given to newborns to prevent cancer.”
Cuccaro added that a proactive presentation by healthcare professionals has a significant effect on vaccine uptake and increases the odds of vaccination ninefold. “Providers should take a presumptive approach and avoid just offering the vaccine as an option. It should be included with regular childhood vaccinations,” she said. “And the advantage of starting early at age 9 is that you can spread the doses out across other regular childhood vaccinations, whereas if you start at age 11, you need to add the HPV vaccine to three other vaccines that are given at that time.”
After age 15, three doses are necessary. “Providers should stress to parents that it’s most effective when given before young people become sexually active and exposed to HPV,” Cuccaro said. And Myers stressed that despite the vaccine’s effectiveness, routine screening for cervical premalignancies is still important.
Despite increasing coverage, vaccination rates have some distance to go before the public health target of at least 80% uptake of the series in the targeted age group, Cuccaro cautioned.
On the global stage, barriers to immunization remain, but the World Health Organization has endorsed a campaign to eradicate cervical cancer through HPV vaccination. It has predicted that the 21st century may be the last to experience HPV-associated cancers, currently responsible for more than 300,000 annual deaths worldwide.
A Brief History of HPV Vaccines
- 1951. Cervical cancer patient Henrietta Lacks’ rapidly dividing cervical cells are collected by George Otto Gey at Johns Hopkins Hospital. They create the first immortal cell line (HeLa) used to study cancers and vaccines worldwide.
- 1976. Harald zur Hausen suggests that genital wart-associated HPV, not herpes simplex, is the probable cause of cervical cancer.
- 1983. HPV is confirmed as a cause of cancer.
- 1991. The first HPV vaccine is developed.
- 2002. Proof of principle and protective efficacy for the monovalent HPV 16 are shown.
- 2006. Merck’s Gardasil 4 (HPV 4) is FDA approved in girls ages 9-26 for protection against strains 6, 11, 16, and 18 — the cause of more than 70% of cervical cancer cases.
- 2009. Approval of Gardasil 4 is expanded to boys ages 9-26 for the prevention of genital warts.
- 2009. The FDA approves GlaxoSmithKline’s Cervarix (HPV 16 and 18) for girls and young women. The vaccine was withdrawn from the US market in 2016 following the success of Gardasil 9 but is used abroad for HPV cancer prevention.
- 2014. The 9-valent recombinant vaccine Gardasil 9 is FDA approved for protection against several low-risk, wart-causing HPV strains as well as the high-risk cancer strains targeted by HPV 4.
- 2018. The FDA expands approval to include females and males 27-45 years old.
- 2020. The FDA extends approval of Gardasil 9 to include prevention not only of cervical cancer but also, vaginal, vulvar, anal, oropharyngeal, and other head and neck cancers.
Annunziata, Cuccaro, and Myers had no competing interests to declare.
A version of this article appeared on Medscape.com.