HPV Reduced Dose Schedule Just as Effective as Standard Dose

According to a press release, a new study supported by GlaxoSmithKline Biologicals, SA, a global healthcare company, girls between 9 and 14 years of age who were given human papillomavirus (HPV)-16/18 ASO4-adjuvanted vaccine in a two-dose regimen during either a 6-month or 12-month interval, appear to have acquired the same level of protection as girls between 15 and 25 years of age who had received a three-dose regimen of the vaccine during a 6-month interval.

The Centers for Disease Control and Prevention (CDC) state that HPV is not only a very common virus, but it also has a high morbidity in that about one in four individuals, around 80 million people, are currently infected within the United States alone. This makes vaccination all the more important.

Between June 2011 and January 2013, 1,447 girls between the ages of 9 and 25 years of age from 33 clinical sites located in Canada, Germany, Taiwan, Italy, and Thailand, were enrolled in the study. Out of the 1,447 girls who were enrolled in the study, 1,428 girls were placed randomly into one of three cohorts. One of the cohorts received a two-dose, 6-month regimen of the HPV vaccine, one cohort received a two-dose, 12-month regimen, and the last group received a three-dose, 6-month regimen. The first two cohorts aforementioned, consisted of girls between the ages of 9 and 14 years. The first cohort received their doses at intervals of 0 months and 6 months, and the second cohort received their doses at 0 months and 12 months. Girls between the ages of 15 and 25 years of age were placed in the third cohort which received a three-dose regimen over the course of 6 months. The girls in the third cohort received their doses of the vaccine at 0, 1, and 6 months. The researchers followed up on the study one month after the girls received their final dose in all three cohorts.

Overall, 534 girls who received the two-dose, 6-month regimen; 394 girls who received two-dose, 12-month regimen; and 427 girls who received the three-dose, 6-month regimen completed the study all the way through to the 1 month follow up. Through serological testing, blood tests that look for antibodies within the blood, the researchers found that the girls in both of the two-dose cohorts were just as protected against HPV as the girls in the three-dose cohort. In addition, when comparing HPV-16 and HPV-18 antibodies between any two of the three regimens, the seroconversion differed by 0.00.

According to the press release, the “geometric mean antibody titer ratios for HPV-16 and HPV-18 were 1.09 (95% confidence interval, 0.97-1.22) and 0.85 (95% CI, 0.76-0.95) for the 6-month two-dose regimen vs. three-dose, and 0.89 (95% CI, 0.79-1.01) and 0.75 (95% CI, 0.67-0.85) for 12-month two-dose regimen vs. three-dose, indicating little statistically significant difference.”

These findings suggest that those infected with HPV will find that the implementation of vaccines are easier and more affordable by being able to reduce their dose schedules. On a larger scale, this creates the potential for more vaccination coverage, and serves to improve protection when it comes to the development of cervical cancer, according to Puthanakit.