HPV Vaccination Offers Long Term Protection Against The Most Virulent Strains of the Virus

Researchers have reported in the Pediatrics journal that boys and girls who received the HPV vaccine enjoy its long term protection against the most virulent strains of the virus. Their conclusions are based on decade of data. These findings have led them to recommend more widespread and early administration of the HPV vaccine even before the exposure of adolescents and preadolescences to the virus.

Fifty percent of all STDs occur in the age group of 15-24; and one in four sexually adolescent females have a STD such as HPV or chlamydia, says the CDC.

HPV is the most common sexually transmitted infection in the US. It is the most common causative factor of cervical cancer. The Centers for Disease Control and Prevention says that 79 million people in the US, most of those in their early 20s and late teens, suffer from human papillomavirus infection. And nearly fifty percent of them are infected with the virus’ most virulent strain. It is these strains that were targeted in the study participants via the quadrivalent vaccine.

Dr. Daron G. Ferris, the first author of the research work, who is a professor, Department of Obstetrics and Gynecology at the Georgia Cancer Center at Augusta University and the Medical College of Georgia, says “The vaccine was virtually 100 percent effective in preventing disease in these young individuals.”

The quadrivalent vaccine offers protection against 4 types of HPV strains including 18, 16, 11 and 6. The first two strains are for all cervical cancers and most other types of cancers caused by HPV such as anal and penile cancers, says the National Cancer Institute. The next two types are for non-cancerous tumor formations in the respiratory tract and some 90% of genital warts.

The 1,661 study participants got a three-dose schedule of the HPV vaccine when they were sexually inactive, and were aged between 9 and15. The researchers found that none of them were affected by the diseases caused by these four strains of HPV virus. The earlier short term analyzation of the patients in 2002 indicated clearly that the vaccine was effective.

Since they wanted to find if it is efficient, provided immunity and is safe in the long term, so that they would know if vaccinating early in life would provide lasting protection. Their research findings concluded a positive answer to their search. They found that the vaccine’s cancer prevention effect was working very much well ten years later. So, these participants will not need a booster vaccine.
Till today, this is the longest follow up study on the vaccine. The participants were tracked at 34 places in 9 countries, including the Georgia Cancer Center in Augusta and MCG. At first, nearly one third of the participants got placebo. The placebo group, however, also were given the vaccine after the study had operated for 30 months. The researchers note that those participants were tracked for a shorter period of time.

The researchers carried out effectiveness evaluation of their patients at 3.5 years after the vaccination, and regularly carried it thereafter twice yearly during the ten year tenure. The evaluation included looking for cancerous and pre-cancerous growths on genitals and cervix, genital warts, and constant HPV infections.

The researchers measured the antibody response in the blood of the participants. They found that though all the participants enjoyed protection from those diseases, those who were vaccinated earlier harbored robust amount of these infection-fighters, both initially and long-term.

Participants of the study reported similar sexual activity like that of other studies. The males were found to have more numbers of new sexual partners than the females. Other STDs like chlamydia and gonorrhea were detected in a small percent of the participants during the tracking period.

Nearly two-thirds of HPV infected individuals can gradually get healed by nature. However, the virus remains and causes many health problems in the individual. Therefore, taking the vaccination is a better way to arm the immune system to remove the virus.

In June 2006, the first quadrivalent vaccine, Gardasil, was approved by the Food and Drug Administration. Currently, it has been approved for people in the 9 to 26 age group. The three-dose quadrivalent vaccine is being rapidly replaced by two-dose vaccines covering 9 strains of HPV. Youth in the US need to be encouraged to get vaccinated, says Ferris.

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