A recent, new study published in the New England Journal of Medicine — which has been hailed as a “milestone” study — confirmed that widespread use of the human papillomavirus (HPV) vaccine dramatically reduces the number of women who will develop cervical cancer. We turned to Darron Brown, MD, a leading authority on HPV, for some answers about this study. Brown is a professor of medicine in the Division of Infectious Diseases and professor of microbiology and immunology at IU School of Medicine and a researcher at the IU Simon Comprehensive Cancer Center.
Do you agree that this is a milestone study? Why or why not?
While other studies have shown that the HPV vaccine is effective against pre-cancerous lesions, this is the first study that conclusively demonstrates that the HPV vaccine prevents invasive cervical cancer. This cancer kills nearly 400,000 women each year worldwide. While cervical screening programs have reduced the incidence of cervical cancer in this country, there are still 15,000 women who die every year from this preventable cancer.
This study, conducted in Sweden, is a milestone in the prevention of cervical cancer. The medical records of approximately 1.7 million girls were examined who were ages 10 to 30 between the years of 2006 and 2017. Some had been vaccinated against HPV and some had not. Invasive cervical cancer developed in 557 women overall, the vast majority in those women who had never received an HPV vaccine. There was an 88 percent reduction in invasive cervical cancer in women who had received an HPV vaccine before age 17 and a 53 percent reduction among women who had received the vaccine at an older age.
Are the study’s findings surprising to you? Why or why not?
The findings of the study are not surprising to me, because the HPV vaccines are highly effective in preventing infection with HPV, the virus that causes cervical cancer. In addition, we know that the HPV vaccines effectively reduce the likelihood of pre-cancerous lesions, which can develop into invasive cancers five to 20 years later. So, it makes sense that the vaccines do what they were designed to do: prevent invasive cervical cancer.
What is the take-away message to the public about HPV vaccination?
Vaccines are the safest and most effective things we do as physicians. Screening programs for cervical cancer are important, but Pap smears lack sensitivity to detect all cervical cancers. In addition, HPV vaccines can prevent other malignancies in both men and women such as oropharyngeal cancer and anal cancer, for which there are no screening programs available.
As I mentioned, the Swedish study showed that the highest reduction of invasive cancers, 88 percent, was demonstrated in the group of young women who had been vaccinated before age 17. This strongly supports the public health policy of vaccinating young boys and girls against HPV at age 11 or 12, before there is a chance of becoming infected.
This study focused on females. What about males and/or the parents of boys/young males? What is the take-away message to them?
Both of my sons have been vaccinated against HPV (and my daughter as well). HPV causes most anal and oropharyngeal cancers. By 2030, more men than women will die from HPV-associated cancers in the United States. It is critical that all boys are vaccinated at age 11 or 12, the same age as for girls.
The study pointed out the need for women in low- and middle-income countries to be vaccinated. As you mentioned in a previous Q&A, nearly 90 percent of all cervical cancer deaths occur in poor and developing countries, such as India, countries in South-East Asia and Sub-Saharan Africa. What can you tell us about your latest work in Africa?
HPV vaccines were FDA-approved in 2006, and approximately 60 percent of girls living in the United States have received the vaccine. However, while 90 percent of all cervical cancer deaths occur in women living in poor countries, few girls are vaccinated against HPV. In Kenya and Malawi, two sub-Saharan countries in which I have worked, fewer than 1 percent of girls have received an HPV vaccine.
We are currently working in Kenya to develop a community-based strategy that will combine screening adult women for cervical cancer with HPV vaccination of children in the same setting. We believe this decentralized approach to cervical cancer eradication will be successful in Kenya and can be applied to other East African countries where cervical cancer is extremely common.