Defeating Infectious Agents — 8

If there’s one success story for a vaccine changing the face of a dreaded disease, it’s the human papilloma virus (HPV) and cervical cancer. Nearly all (99.7%) cases of cervical cancer are attributed to chronic HPV infection. HPV infections enter the genital mucosa surfaces and only low levels of antibodies are formed, which takes more than eight months. Two or three sequential HPV vaccine shots achieve sterilizing immunity—preventing entry of the virus into cells, preventing infections for what may well be the lifetime of the individual. This is “superhuman immunity” because it defies the adage that natural infections induce better immunity than vaccines. It’s not the only example; similar vaccine-induced immune response superiority over natural infections is seen with tetanus, Hemophilus influenza type b, and varicella zoster (which can lead to shingles).

The clinical impact of HPV vaccination is nothing short of remarkable. The first national cohort to monitor the long-term outcome of vaccination was Scotland, where it became routine in 2008 with nearly 90 percent of girls aged twelve to thirteen getting at least one dose of the three-dose protocol. How many cases of cervical cancer in these forty thousand women were later found? None. Zero! Even older girls greatly benefited from the vaccination, with a 62 percent reduction from 8.4 per 100,000 women in unvaccinated to 3.2 cases per 100,000 women who received the full vaccine protocol.

Back in the United States, the HPV vaccination rate remains alarmingly low, at approximately 60 percent. Meanwhile, cervical cancer kills more than three hundred thousand women each year. Worldwide, only one in five have had the vaccine. Head and neck cancers, particularly involving the throat, are the most common malignancy caused by HPV. Those cancers have an even higher number of cases per year than cervical, and the vaccine is FDA approved and highly effective for yet another type of cancer. Men can benefit by marked reduction of head and neck cancers, but their uptake, aged twenty-seven to forty-five years of age, is less than one-third of women. Here we have the prototypic superhuman immunity vaccine, which is exceptionally safe at preventing HPV cancers, but the familiar and daunting problem of inadequate population vaccination that could lead to their eradication. That is a problem we cannot ignore.