HPV vaccine and herd immunity in men

prior articles have suggested that there is “herd immunity” from the increasing rates of HPV vaccination in the community, leading to decreased prevalence and transmission of the vaccine-type infections to those who never were immunized (see below). A new study detected herd immunity against oral HPV infections, especially in men (see hpv dec in unvaccinated jama2019, or Chaturvedi AK. JAMA. 2019; 322: 979).

Details:
-- four cycles of the National Health and Nutrition Examination Survey (NHANES) were reviewed, a cross-sectional survey of the US population that included HPV analysis from oral rinses
-- mean age 39, 65% white/12% black/16% Hispanic, 55% never smoker/20% former smoker/23% current, lifetime oral sex partners: 35% had 0-1/40% had 2-5/13% had 6-10/10% had more, oral sex partners in past 12 months: 35% had zero/54% had 1/11% had more

Results:
-- 13,676 people aged 18 to 59 from 2009-2016: HPV vaccination rates (defined as at least one dose of vaccine) increased from 0% to 5.8% in men and from 7.3% to 15.1% in women
-- unvaccinated men aged 18 to 59:
    -- vaccine-type oral HPV prevalence declined 37%, from 2.7% in 2009-10 to 1.6% in 2015-16, with adjusted prevalence ratio 0.63 (0.44-0.90), p=0.009 for trend
    -- non-vaccine type oral HPV prevalence was unchanged (8.6% in 2009-10, 8.4% in 2015-16)
-- unvaccinated women aged 15 to 59:
    -- vaccine-type oral HPV prevalence unchanged, 0.6% in 2009-10 to 0.5% 2015-16
    -- non-vaccine type oral HPV prevalence was also unchanged, 2.6% in 2009-10, 3.3% in 2015-16

Commentary:
-- studies have shown HPV vaccine efficacy in reducing oral HPV infections; though, because of lack of randomized trials, there is no vaccine recommendation regarding the prevention of oral infections or oropharyngeal carcinoma (and, as noted in the prior blog below, it is only in the past few months that the CDC increased the recommended age for HPV vaccination in males to parallel that of females). The above observational study is important in light of the increasing incidence of HPV-positive oropharyngeal cancers in the US
    -- a study done by the same authors of the above study noted the 4-valent HPV vaccine led to an 88% reduction in oral HPV infections by the covered vaccine types of 16, 18, 6, or 11. This was true in both men and women but more so in men
-- the above data in men do suggest that there was herd immunity for unvaccinated men, since there was decrease in only the vaccine-specific HPV types, with no evident change in women
    -- not clear why this was not the case in women. One issue is that the incidence of oral HPV infections in women was significantly lower in men, so the statistical power to show a relationship was lessened. Also, women did have significantly lower numbers of lifetime or recent oral sex partners.
    -- And, likely consonant with these data, men seem to have more oropharyngeal carcinomas, at this time outpacing the number of cervical carcinomas in women (see http://gmodestmedblogs.blogspot.com/2017/10/oral-hpv-in-men-and-oropharyngeal-cancer.html)
--a prior study in women found that in those 14-19 yo, when 55% of them had at least one HPV vaccine, the prevalence of HPV types covered in the  4-valent vaccine decreased from 11.5% in 2003-6 to 3.3% in 2011-14; and in 20-24 yo, when 43% of them had at least one HPV vaccine, it decreased from 18.5% to 7.2%
    --and, in those 14-24 year olds who were sexually active, it decreased from 89% in those vaccinated and 34% in those not vaccinated (see Oliver SE, J Infect Dix Sep 1; 216(5):594, or doi: 10.1093/infdis/jix244): ie, there was clear herd immunity, but that is also clearly not as effective as getting the vaccine directly
-- see https://gmodestmedblogs.blogspot.com/2019/08/cdc-recommends-hpv-vaccine-to-age-26.html  for the CDC HPV recommentations and reference to the study on herd immunity in women from genital HPV infections

So, this NHANES trial extends the previously found herd immunity in women for vaginal HPV infections to men for oral HPV infections. It is notable that the 37% decline in men happened in the setting of relatively small increases and still quite low percentages of HPV vaccination rates in men. This is similar to the remarkably protective herd immunity in adults from vaccine-specific pneumococcal disease from regularly immunizing kids with the PCV-13 vaccine (referenced in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457056/#b19-ad-10-2-404 ).

This new study therefore does reinforce the importance of extensive, community-wide HPV vaccination. and, the earlier, the better (eg immunizing the 9 year olds...)

see https://gmodestmedblogs.blogspot.com/2019/08/response-to-cdc-recommends-hpv-vaccine.html for the CDC HPV recommendations (and a response), along with links to many relevant HPV vaccine blogs
and, http://gmodestmedblogs.blogspot.com/2017/10/oral-hpv-in-men-and-oropharyngeal-cancer.html for a blog from NHANES showing the high rates of oral HPV infection in men

geoff​

If you would like to be on the regular email list for upcoming blogs, please contact me at gmodest@uphams.org

to get access to all of the blogs:

1. go to http://gmodestmedblogs.blogspot.com/ to see them in reverse chronological order

2. click on 3 parallel lines top left, if you want to see blogs by category, then click on "labels" and choose a category​

3. or you can just click on the magnifying glass on top right, then  type in a name in the search box and get all the blogs with that name in them

please feel free to circulate this to others. also, if you send me their emails, i can add them to the list