- Category: HPV Vaccines
- Published on Tuesday, 08 November 2016 00:00
- Written by Liz Highleyman
Adolescents age 11-14 years can receive 2 doses of the human papillomavirus (HPV) vaccine to prevent cancers caused by HPV, rather than the 3 doses previously recommended, according to the U.S. Centers for Disease Control and Prevention (CDC). This change is supported by a systematic review presented at the recent IDWeek meeting in New Orleans, which found that 2 vaccine doses were non-inferior to 3 doses for this age group.
"Safe, effective, and long-lasting protection against HPV cancers with two visits instead of three means more Americans will be protected from cancer," CDC director Tom Frieden, MD, MPH, said in a media statement. "This recommendation will make it simpler for parents to get their children protected in time."
Human papillomavirusis a sexually transmitted virus that can cause genital warts and cervical, anal, and other genital cancers. A majority of people become infected with some of the many strains of HPV soon after they become sexually active, so vaccination is recommended before this point.
The CDC's Advisory Committee on Immunization Practices(ACIP) recommends routine HPV vaccination for girls and boys at age 11-12, but the vaccine can be given as early as age 9, or as late as age 21 for most men or age 26 for women and for gay and bisexual men or immunocompromised men, including those living with HIV.
The newest HPV vaccine, Merck's Gardasil 9, protects against 9 different HPV strains that cause genital-anal warts (6 and 11) or cancers (16, 18, 31, 33, 45, 52, and 58). An older version of Gardasil that was effective against 4 HPV types (6, 11, 16, and 18) has been phased out, along with GlaxoSmithKline's Cervarix, which protected against only 2 types (6 and 18).
On October 7 the U.S. Food and Drug Administration (FDA) approved adding the 2-dose schedule for the 9-valent Gardasil HPV vaccine for adolescents age 9-14.
The ACIPvoted unanimously on October 19 to recommend the 2-dose schedule based on a review of data from clinical trials showing that 2 doses of the vaccine for adolescents age 9-14 produced immune responses similar to or higher than 3 doses for young adults age 16-26.
Based on these findings, teens and young adults who start the HPV vaccine series after age 14 should still get 3 doses.
Elissa Meitesand Lauri Markowitz from the CDC's National Center for Immunization and Respiratory Diseases conducted a systematic review of evidence evaluating a 2-dose HPV vaccine schedule. Reducing the number of doses would lower cost and increase convenience for patients, parents, and providers.
The researchers searched PubMed and clinicaltrials.gov for studies published between January 2006 and June 2016 in which 2 HPV vaccine doses were administered over at least 6 months to girls or boys age 9-14. They identified 131 studies of interest and selected 7 relevant studies for inclusion in evidence tables.
They found that studies of each of the 3 licensed HPV vaccines demonstrated that 2 doses administered 6 to 12 months apart to people age 9-14 produced non-inferior immunogenicity -- or ability to induce an immune response -- when compared to 3-dose schedules administered at 0, 1-2, and 6 months to women in the age group for whom efficacy was demonstrated in clinical trials.
The researchers concluded that there is "moderate evidence" supporting 2-dose schedules for HPV vaccination.
E Meites and L Markowitz. Systematic review of evidence for 2-dose HPV vaccination schedules. IDWeek. New Orleans, October 26-30, 2016. Abstract 719.
Centers for Disease Control and Prevention. CDC recommends only two HPV shots for younger adolescents. Press release. October 19, 2016.