March 11 (UPI) — Vaccination against human papillomavirus, or HPV, provides limited health benefits for adults aged 26 and older at a high cost to the healthcare system, according to a study published Thursday by PLOS Medicine.
While roughly 300,000 cases of cervical cancer are likely to be diagnosed among women born between 1969 and 2009, researchers say the cost difference between vaccinating only adolescents and inoculating all adults up to age 45 ranges from about $ 485,000 to over $ 1 million per year of life gained — and it may not be worth it.
“While some individuals over the age of 26 may benefit from HPV vaccination, the public health value of vaccinating up to age 45 is quite low,” study co-author Jane J. Kim told UPI.
“The target ages for routine HPV vaccination, age 11 to 12, are optimal,” said Kim, a professor of health economics at the Harvard T.H. Chan School of Public Health in Cambridge, Mass.
Currently, the Centers for Disease Control and Prevention recommends that adolescents age 11 to 12 be vaccinated against HPV, with “catch-up vaccination” advised for both males and females up to age 26 who may have been older than the “target” age when the vaccine was approved by the Food and Drug Administration in 2014.
That vaccine, Gardasil, can be used in children as young as age 9 and in adults up to 45, according to the CDC.
Rates of cervical cancer, once the deadliest cancer among women 40 and younger in the United States, have been declining over the past 30 years, due in part to the availability of pap smear tests, as well as the vaccine, the agency said.
For this study, Kim and her colleagues used two mathematical models that simulated HPV infection and cervical cancer cases, as well as diagnoses of five non-cervical HPV-related cancers and genital warts.
They used the models to project the lifetime costs, benefits and cost-effectiveness of extending HPV vaccination to both women and men up to age 45 in the United States.
To estimate long-term outcomes associated with extending HPV vaccination, they projected the lifetime health and economic consequences for vaccinated and unvaccinated older adults, taking into account historical HPV vaccination in younger groups and current cervical cancer screening among women.
Findings from both models suggest that HPV vaccination beyond age 26 has limited health benefit and is not cost-effective, even when assuming that the vaccine offers 95% protection.
Vaccinating all adults age 26 to 45 against HPV reduced the number of cervical cancer diagnoses among women born between 1969 and 2009 by roughly 25,000, at a cost of up to just over $ 1 million for each year of healthy life gained.
Even when factoring in reductions in the numbers of other HPV-related cancers — anal, vulvar, vaginal, penile and oral — as well as genital warts, vaccinating this older population still costs up to $ 440,000 per year of healthy life gained.
The findings suggest that HPV vaccination for adult women and men older than 26 “is unlikely to represent good value for money in the United States,” they said.
The study results contributed to the 2020 decision of the Advisory Committee on Immunization Practices, part of the CDC, to not recommend catch-up vaccination beyond age 26, according to the researchers.
“We do not question the benefits and value of HPV vaccination up to age 26,” Kim told UPI.
“The health impact and cost-effectiveness of HPV vaccination is greatest when vaccines are administered before exposure to HPV — that is, before sexual initiation,” she said.