New research looking into the long-term effects of the human papillomavirus (HPV) vaccine has found it to be both safe and effective in protecting against the most virulent strains of the virus.
Led by Dr. Daron G. Ferris, professor in the Department of Obstetrics and Gynecology at the Medical College of Georgia and at the Georgia Cancer Center at Augusta University, the study is the longest followup to date on the vaccine, looking at data from 1,661 male and female participants who were followed for just under ten years.
Of these participants, around two thirds received a three-dose regimen of the vaccine when they were ages 9-15 and sexually inactive.
Initially about one third received a placebo not a vaccine, however the placebo group also received the vaccine 30 months into the study, meaning that these individuals were followed a shorter period of time.
Dr Ferris found that the vaccine was virtually 100 percent effective in preventing the disease, although vaccinating earlier produced the most robust initial and long-term antibody response, the proteins found in the blood which help fight infection.
"We needed to answer questions like if we vaccinate earlier in life, will it last," explained Dr Ferris, "The answer is yes, this cancer prevention vaccine is working incredibly well 10 years later. A booster vaccine likely will not be needed by these young people. I think now we have come full circle."
The new finding also supports previous research which suggests that a more widespread and earlier administration of the HPV vaccine, before teens and preteens are exposed to the infection, is the preferred option.
Although the disease can be cleared in around two-thirds of infected individuals, the virus can persist in the remaining one-third, potentially causing causing a wide range of further health problems.
The quadrivalent vaccine, which protects against HPV types 6, 11, 16 and 18, is designed to better arm the immune system to eliminate the virus.
According to the National Cancer Institute, HPV types 16 and 18 account for essentially all cervical cancer and for most other HPV-related cancers such as penile and anal cancers. Types 6 and 11 account for about 90 percent of genital warts as well as non-cancerous tumor growths in the respiratory tract.
HPV is the most sexually transmitted infection in the USA. Around 79 million Americans, most in their late teens and early 20s, are infected according to the Centers for Disease Control and Prevention. HPV is also the most common cause of cervical cancer.
The Food and Drug Administration approved the first quadrivalent vaccine, Gardasil, in June 2006, with the vaccine currently approved for patients ages 9-26.
Although the CDC reports that around 43 percent of US teens are up to date on recommended doses of the HPV vaccine, Dr. Ferris added that, "Now we need to push for more young people to get vaccinated. We are doing miserably in the United States."
The HPV researchers added that the vaccine can be given along with the meningococcal and tetanus, diphtheria and pertussis vaccines, to 11- and 12-year-olds.
The results can be found published online in the journal Pediatrics.