Gardasil 9 Approved for More Effective Prevention of Cancers
Last week, the Food and Drug Administration approved the new Gardasil 9 vaccine, for the prevention of various diseases caused by nine types of Human Papillomavirus (HPV). It is not yet available for clinical use but should be over the next several months.
The prior vaccine Gardasil, which was approved in 2006, covered four types of HPV: the two ‘low-risk’ types 6 and 11, which account for 90% of genital warts, and the two ‘high-risk’ types 16 and 18, which account for 70% of cervical and some additional cancers.
Gardasil 9 affords the same protection against those same four types, plus against five additional high-risk types: 31, 33, 45, 52 and 58. These additional types collectively account for 20% of cervical cancers.Thus, Gardasil 9 will protect against 90% of genital warts and 90% of cervical, vulvar, vaginal and anal cancers.
Though not discussed in the FDA approval, penile cancer and certain head and neck cancers have also been associated with HPV, especially types 16 and 18, and this vaccine may afford similar protection against those.
Also not yet addressed by the FDA: should people who have already received Gardasil now get Gardasil 9? My thoughtful impression is YES! Although types 16 and 18 are the most prevalent types responsible for cancers, types 31 and 45 are also relatively prevalent and are also responsible for many cancers, which can be prevented with Gardasil 9.
Gardasil 9 has initially been approved for use in females aged 9 through 26 and males aged 9 through 15. Once additional studies are performed, it will likely be approved for males aged 16 – 26 as well.
There are at least 170 types of HPV, approximately 40 of which can affect the genitals and are thus considered to be sexually transmitted diseases. In North America, the strains most common in women with invasive cervical cancer are 16, 18, 45, 31, 33, and 52, respectively.
Another vaccine, Cervarix, protects only against HPV types 16 and 18; it is uncommonly administered in the United States.
Gardasil 9 is administered as three separate shots, with the initial dose followed by additional shots given two and six months later. Gardasil 9’s full benefit is achieved by vaccinating prior to becoming infected with the HPV strains covered by the vaccine.
The safety of Gardasil 9 was evaluated in approximately 13,000 males and females. The most commonly reported adverse reactions were injection site pain, swelling, redness, and headaches.
Remember that vaccination does not eliminate the necessity for women to continue to undergo recommended cervical cancer screening.
These vaccines have not been demonstrated to provide protection against disease from vaccine and non-vaccine HPV types to which a person has previously been exposed through sexual activity.
These vaccines are not intended to be used for treatment of active external genital lesions; cervical, vulvar, vaginal, and anal cancers, or their precursors.
These vaccines have not been demonstrated to protect against diseases due to HPV types not contained in the vaccine.
Vaccination with Gardasil 9 may not result in protection in all vaccine recipients. 97% are expected to be covered.