The HPV vaccine is safe and cuts cervical cancer risk by 80%, 2 large reviews find

The HPV vaccine is very safe and very effective in preventing cervical cancer, according to two comprehensive studies that support routine vaccination of adolescents against the human papillomavirus.

HPV is the most common sexually transmitted infection and can cause genital warts. Merck’s Gardasil vaccine, the first version of which was approved in 2006, protects against nine strains of cancer-causing HPV.

Nearly 60 randomized controlled clinical trials involving 160,000 participants, considered the gold standard for scientific research, have indicated that HPV vaccination is effective in preventing infection, as well as precancerous cervical lesions and genital warts. The two papers, published recently by the highly respected British Cochrane Review team, also included 225 observational studies involving more than 132 million people worldwide. Together, the studies showed that girls vaccinated against HPV before age 16 had an 80% lower risk of cervical cancer.

“The vaccine works. Period,” said Dr. Linda Eckert, a professor of obstetrics and gynecology at the University of Washington and an expert on the causes of cervical cancer. “The vaccine is safe. Period.”

Eckert, who was not involved in the evaluations, praised them as “methodically rigorous,” “robust” and “benchmark.”

The new reports are supported by recent real-world findings. In late November, an Australian cervical cancer research organization announced that, almost certainly as a result of HPV vaccination, there were no new cases of cervical cancer in 2021 among women under 25, a milestone not seen since data was collected starting in 1982. Last year, Scotland’s public health agency found there were no new cases of cervical cancer in women fully vaccinated when young.

“We did a social media search, looking at everything people said HPV was associated with,” said Jo Morrison, lead author of the Cochrane reviews and consultant in gynecological oncology at Somerset NHS Foundation Trust in England. According to his team’s documents, the claims included that the vaccine caused infertility, chronic fatigue syndrome and paralysis. “What we found is that the evidence shows very clearly that there is no connection to the different things that people are worried about,” she said.

Specifically, the team found that serious adverse health effects were rare and occurred at similar rates whether trial participants received the vaccine or a placebo.

The criticism comes as Health and Human Services Secretary Robert F. Kennedy Jr., an anti-vaccine activist, has increasingly stepped up his control over childhood immunizations overall.

Kennedy benefited financially from vaccine injury lawsuits against Merck, the manufacturer of the Gardasil HPV vaccine. In 2019, he called Gardasil “the most dangerous vaccine ever made.” Pressed during his Senate confirmation hearing by Sen. Patty Murray, D-Wash., Kennedy declined to say whether the vaccine was safe.

HHS did not return a request for comment.

The Centers for Disease Control and Prevention, under guidance established before Kennedy’s tenure at HHS, recommends vaccinating boys and girls against HPV between ages 11 and 12, before they become sexually active. More broadly, the agency recommends Gardasil for ages 9 to 26. People up to 45 years old are eligible for vaccination.

The strains of HPV targeted by Gardasil can cause multiple cancers in men and women, including anal, vulvar, oropharyngeal (back of the throat), vaginal, and penile cancer. Approximately 48,000 cases of HPV-related cancer, including some 13,360 cases of cervical cancer, are diagnosed each year in the United States.

However, since HPV vaccination began, the rate of cervical cancer in the United States fell 65% between 2012 and 2019 among women in their early 20s — the first U.S. cohort to receive the vaccine, according to a 2023 study from the American Cancer Society.

Morrison said the Cochrane reviews probably couldn’t definitively determine that the HPV vaccine prevents cervical cancer because other HPV-related cancers typically take longer to develop. For now, it’s unclear whether vaccination reduces rates of other cancers, she said.

Concerns about Gardasil have persisted since its first approval two decades ago.

Morgan Newman, 35, of Norwalk, Iowa, was offered the HPV vaccine during a doctor’s appointment the year Gardasil was approved. Then aged 16, she went against her parents’ wishes and refused, believing that the vaccine was too new and that she did not know enough about it.

Eight years later, she was diagnosed with cervical cancer. She underwent chemotherapy and radiotherapy, but the cancer metastasized two years later.

“You are on the verge of death,” she remembers of the brutal treatment that led to infertility.

After nearly a decade in remission, Newman is an outlier when it comes to surviving stage IV cervical cancer.

“Cancer is a gift wrapped in barbed wire,” she said, noting that she lives with lymphedema, a lifelong side effect of chemotherapy that causes painful fluid retention. “I’m grateful to be here, but I want to make sure everything I do has a purpose.”

She became a social worker and volunteer for Cervivor, a cervical cancer advocacy nonprofit.

Newman recalled her teenage mindset about the possibility that she might one day develop a vaccine-preventable cancer. “I told my mother, ‘No, that will never happen to me,’” she said.

According to data from the CDC’s annual survey, HPV vaccination rates, disrupted by the Covid pandemic, remained stable among 13- to 17-year-olds from 2022 to 2024. About 78% of these adolescents ultimately received at least one dose and 63% completed multidose vaccination. Meanwhile, rates of other CDC-recommended vaccinations for adolescents have increased over this period and exceeded 90%.

A 2024 study published in The Lancet Regional Health found that white families in the United States and those with higher incomes were less likely to intend to vaccinate their children against HPV; security concerns were the most common reason.

Concerns include that providing an STI vaccine could potentially lead to sexual risk-taking among children, although research at Harvard University found no evidence to support this.

A Seattle mother who asked that her name not be used for privacy reasons said she was hesitant when her pediatrician recommended Gardasil for her teenagers, now 15 and 17.

“I remember thinking, well, my kids aren’t sexually active,” the 49-year-old mother said of the prospect of getting an STI vaccine. “Then I thought, well, we might as well do it. Let’s cover all the bases.”