Thursday, February 09, 2012

New 2012 vaccine recommendations in USA - Why is Cervical Cancer vaccine being recommended for boys ?

There are more than a dozen changes in the latest 2012 children, adolescent and adult immunization recommendation in the USA. 
One of the major changes in the 2012 children and adolescent vaccination schedule in the USA is the recommendation for giving the Cervical cancer vaccine to boys aged 11-12 years.
Why is this being recommended ? Here is what Dr. Brady, Chairperson, American Academy of Pediatrics Committee on Infectious Diseases has to say. 

Medscape: In October 2011, the Advisory Committee on Immunization Practices voted to recommend routine use of human papillomavirus quadrivalent vaccine (HPV4) in boys aged 11-12 years, and this recommendation is included in the 2012 schedule. Can you discuss some of the reasons for this recommendation, a stronger position than the Advisory Committee's previous recommendation that HPV4 may be given to boys to prevent genital warts?
Dr. Brady: When the HPV vaccines -- HPV4 or HPV2 -- were created, it was with the goal of prevention of cervical cancer. It was known that there are HPV strains that could also produce genital warts, and so those initial studies were primarily done in females. As you know, HPV is a sexually transmitted disease. If you look at mathematical modeling, it appears that if you had coverage of females in the range of 80% or more, you might be able to reduce heterosexual transmission to the point that you could have a benefit for both males and females.
A couple of things have happened since the initial approval. First of all, we haven't had an uptake above 80% for the entire series, and so we have not been successful in trying to implement a public health approach that is going to have a significant impact on heterosexual transmission of HPV. Because males are also participants in heterosexual transmission, this was an opportunity to approach the issue of transmission in another way.
Additionally, it became clear that HPV not only causes cervical cancer but is also capable of causing a number of other cancers, particularly oropharyngeal cancers, which have been increasing dramatically over the past couple decades. Those occur in both genders. Therefore, it was recognized that there would be a significant health benefit to males from receipt of the vaccine for the prevention of oropharyngeal cancers.
The other thing that was recognized was that giving HPV vaccine to females only does not have any impact on transmission of HPV between men who have sex with men. That is a group that has significant risks for both cancers as well as genital warts.
When you put all of the different new pieces of information together, it became very clear that a female-only approach was not going to reduce cervical cancer, oropharyngeal cancer, the other cancers that are seen, and genital warts, as would be seen with a gender-neutral approach.
By having a gender-neutral approach and identifying HPV vaccine as primarily a cancer vaccine, we are also hoping that it will approve acceptance to a greater degree than has been seen with singling out one particular gender. We are just going to make it a routine practice for all children. We hope that that will improve acceptability and eventually get us above the 80th percentile for both.
My view - So male cervical cancer vaccine is being promoted for essentially 4 reasons ...
1. May prevent heterosexual transmission - since males are carriers
2. May prevent gay / homosexual transmission 
3. May prevent other cancers caused by HPV - like oropharyngeal cancer.
4. By making it gender neutral, may increase immunization coverage.
To me, from a strictly epidemiological perspective, the first point is most important. And from a practical point of view, the last point also seems appropriate. Though convincing parents regarding the applicability of cervical cancer vaccine for their son may be difficult.
MSM (Male sex with male) and other HPV related cancers are relatively less common, and to my mind right now may not be appropriate indication for universal vaccination in all kids. 

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