Fewer doses of HPV vaccine may be enough to protect against cervical cancer

Fewer doses of HPV vaccine may be enough to protect against cervical cancer

A new study shows that one or two doses of the HPV vaccine may be as effective as three doses against severe cervical abnormalities in girls and young women. The findings could have significant implications for global efforts to eliminate cervical cancer.

A recent study by researchers at Karolinska Institutet, published inThe Lancet Regional Health – Europeindicates that one or two doses of the HPV vaccine given before age 17 provide comparable protection against severe cervical lesions as three doses. The study is based on data from over 2.2 million Swedish girls and women and tracks the effects of vaccination over a period of up to 17 years.

Our findings support World Health Organization (WHO) recommendations that one or two doses may be enough to protect girls and young women from cervical cancer.”

Shiqiang Wu, Research Associate, Department of Medical Epidemiology and Biostatistics, Karolinska Institutet

Cervical cancer is the fourth most common cancer in women worldwide, causing over 340,000 deaths in 2020. The WHO has set a goal of eliminating cervical cancer as a public health problem by the end of the century. One of its main goals is a 90% vaccination rate for girls before the age of 15.

“Our results strengthen the evidence that one or two doses of the HPV vaccine may be enough, which could help vaccinate more girls and accelerate efforts to eliminate cervical cancer,” says Jiayao Lei, assistant professor at the Department of Medical Epidemiology and Biostatistics Division of Clinical Science, Intervention and Technology, Karolinska Institutet.

The study is based on data from Swedish national registries, including information on vaccinations and the occurrence of high-grade cervical lesions in women aged 10 to 35 years between 2006 and 2022. To ensure that the results were not influenced by factors such as socioeconomic background and maternal history of severe cervical lesions, the researchers adjusted these variables. The results show that young girls who received one or two doses of the HPV vaccine before the age of 17 had a comparable risk of severe cervical abnormalities as those who received three doses.

The research highlights a potential breakthrough in reducing the number of vaccine doses required. However, researchers emphasize that further studies are needed to understand the duration of protection and whether a booster dose may be needed in the future.

“The next step is to monitor those who have received less than three doses for a long period of time to ensure continued protection against cervical cancer and to study the effect of the new 9-valent vaccine,” concludes Jiayao Lei.

The study shows the protective effect of fewer doses and supports reducing the number of doses to make vaccination more accessible worldwide, particularly in low- and middle-income countries where the burden of cervical cancer is greatest.

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