How time flies when you introduce a new vaccine—and that is certainly true for the human papilloma vaccine (HPV), which was introduced 14 years ago in 2006 as a 4-valent vaccine but has now been enhanced as a 9-valent vaccine. When the vaccine first became available, the 4-valent vaccine-type HPV was detected in 35% of women ages 13-26 in two different clinical sites, according to a new study by Spinner et al. (10.1542/peds.2018-1902). The good news is that over the next 11 years, vaccination rates increased from essentially to 84.3% while prevalence of 4-valent vaccine-type HPV decreased from 35% to 6.7%. The study also identified strong protection from herd immunity.
How important are these findings? Very important, per an accompanying commentary by Dr. Amanda Dempsey from the University of Colorado (10.1542/peds.2018-3427). Dr. Dempsey underscores how important the high effectiveness of this 4-valent type vaccine is by reducing vaccine-type HPV prevalence in vaccinated and unvaccinated herd-immune women—and interestingly enough, the reduction in prevalence included a reduction in the 5 additional types in the 9-valent vaccine, even though most women in the first 5 years of the study did not get this newer vaccine. With this cross-protection, Dr. Dempsey emphasizes that needing to reimmunize teens who only got the 4-valent vaccine with the 9-valent vaccine is probably not warranted. Yet those who did not get the 4-valent vaccine are not showing immunity to the 9-valent vaccine as those vaccinated did, but instead had higher odds of infection with the 5 added HPV types. Dr. Dempsey speculates on why the higher risk of the 5 added serotypes in unvaccinated women is occurring, and the role of “cross” protection in those who have been vaccinated. Both this study and commentary make some sharp points about the importance of teens being vaccinated to HPV for themselves and to protect others less likely to seek vaccination but who are at least protected to 4-valent type from a herd-immunity standpoint. Read both and then share the findings with patients and families who are reluctant to receive this vaccine. The data presented in the study and commentary might convince them to think again and get a vaccine that may be all it takes to reduce their risk of cervical or genital cancer.
