Date: January 28th, 2020
Author: Nina Shapiro
While widespread vaccination continues to be a source of contention in this country and others, one of the newer vaccines has begun to demonstrate remarkable positive impact, which will hopefully become harder and harder to dispute. The HPV vaccine, with trade name GardasilR, is recommended for both boys and girls, ideally sometime between ages 11 and 12 years, given in two doses at a six month interval. It can be given as early as age 9, and as late as age 26. Older adults, even up to age 45, can receive the vaccine, although it is more likely that these adults have already been exposed to the virus, and are less likely to be protected by the vaccine.
The vaccine prevents infection with the human papillomavirus (HPV), which can cause health problems ranging from nuisance-causing warts to cancer-causing lesions of the cervix, throat, and anorectal area. When HPV-related cancers hit Hollywood, with Michael Douglas publicly attributing his throat cancer to HPV, it became clear that this disease can no doubt affect both men and women. When Marcia Cross announced that her anal cancer was due to HPV infection, it raised yet another red flag that HPV can affect the lower gastrointestinal tract, not just the female reproductive tract. Indeed, HPV can affect any of us, at any age, from stem to stern. As I wrote in an earlier Forbes piece, the vaccine to prevent HPV can prevent not only sexually transmitted infections (STI’s) causing genital warts, but it can also prevent cancer.
A lesser known impact of active HPV infection is that the virus can be transmitted from pregnant mother to her fetus via amniotic fluid. The child can later (usually as a toddler) develop warts on the vocal cords, known as recurrent respiratory papillomatosis, or RRP. These warts lead to progressively worsening airway blockage, and even death. And while there are treatments for RRP, there is no cure; only prevention. In another Forbes article, I explain how reduction of HPV infections, thanks to vaccine programs, can reduce the incidence of RRP in the next generation.
A report released this week by Public Health England, published in Health Protection Report, reviewed surveillance data from outcomes of a national HPV vaccination program, which began in 2008. The vaccine is offered to 12-13 year-old males and females, and the report then looked at incidence of HPV infection of the reproductive tract in sexually active 16-24 year-old females. As is the case with many viruses, HPV has many subtypes, some of which are more likely to be associated with aggressive cancers (subtypes 16 and 18 as well as 31, 33, and 45) and others are more likely to be associated with RRP infections and genital warts (subtypes 6 and 11). Until 2012, the bivalent (HPV 16/18) vaccine (CervarixR) was administered as a three-dose regimen. In years since then, the quadrivalent (HPV 16/18/6/11) (GardasilR) has been the standard vaccine administered in the U.K. as well as the U.S. as a two-dose regimen. Cervical cancer is due to HPV 16 or HPV 18 in up to 80% of cancers.
The recent report out of the U.K. analyzed results of over 18,000 vulvovaginal culture specimens obtained from sexually active 16-24-year-old females, collected between 2010 and 2018. There was significant decline in HPV infection rates in all subtypes in all age groups. Those who had been vaccinated more recently showed more reduction in HPV 6/11 than those who did not receive coverage for these strains in the earlier years of vaccination. Most notable was that the prevalence of HPV 16/18 in the 16-18-year-old cohort declined from 8.2% in 2010 to 0.0% in 2018. In the older groups, there was less decline (from 14% to 0.7% in 19-21-year-olds and 16.4% to 2.6% in 22-24-year-olds), but all reductions were statistically significant.
There was no evidence of increase in the HPV subtypes which were not included in the vaccine. Some have raised concern that vaccinating against specific HPV subtypes would increase growth of subtypes not included in the vaccine, but this was not found to be the case. While there are several limitations to this report, including the fact that each individual sample was not identified as being from a vaccinated or non-vaccinated individual, this marked reduction of all HPV subtype growth in a population which demonstrated a vaccination rate of 86% for both males and females ages 12-13 years is promising. While not all cervical cancers, throat cancers, or anal cancers are directly caused by HPV infection, the high rates of HPV-related cancers due to known HPV subtypes underscores the potential widespread benefits of this vaccine in the decades ahead.