A single dose of the HPV vaccine could be enough to protect against cervical cancer rather than the three now recommended, a new analysis suggests.
Cervical cancer is the fourth-most common cause of cancer death of women worldwide, killing an estimated 260,000 women every year. In the U.S., each dose of the vaccine costs roughly $100, and young girls typically begin getting vaccinated around age 11 to 12.
Researchers form the U.S. National Cancer Institute examined data from the trials of 24,000 young women to measure how much protection they received from one, two or three doses of Cervarix, the HPV vaccine made by Glaxo. They estimated that after about four years, vaccine effectiveness is between 77 percent and 86 percent for all the young women, regardless of how many shots they received. The study was published Wednesday in the journal Lancet Oncology.
Julia Brotheron, medical director of the National HPV Vaccination Program Register in Australia, says that it is not clear why one dose appeared to be so effective, but suggested that the “virus-like” particle used to make the vaccine might have provoked a particularly strong response from the girls’ immune systems.
A similar vaccine, Gardasil, is sold by Merck & Co. Experts say that it is possible that Gardasil would work with fewer doses since Gardasil is also made with virus-like particles.
Authors of the study acknowledge that it is not convincing enough to immediately change vaccine strategies, but if results are confirmed, requiring one dose could have a large impact on how many girls around the world get immunized.
Study co-lead author Dr. Aimée Kreimer of the U.S. National Cancer Institute said,
Our findings question the number of HPV vaccine doses truly needed to protect the majority of women against cervical cancer, and suggest that a one-dose schedule should be further evaluated. If one does is sufficient, it could reduce vaccination and administration costs as well as improve uptake.”
Read more here- “Study: Vaccine against cervical cancer might work after just 1 shot instead of 3” (Maria Cheng, Associated Press)
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