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HPV Vaccine Trial in Costa Rica

The HPV Vaccine Trial in Costa Rica is a collaboration between investigators in Costa Rica and the National Cancer Institute. The trial was designed as a blinded, randomized, phase III clinical trial to evaluate the efficacy of a bivalent HPV-16/18 virus-like particle (VLP) vaccine. The vaccine used in the trial was developed by investigators at NCI and other research institutions and is manufactured by GlaxoSmithKline Biologicals. The trial was initiated on June 28, 2004 and enrollment was completed on December 22, 2005; there were 7,466 women enrolled. 

Trial staff followed all enrolled women for a period of four years. Women who were eligible, consented, and were randomized into the trial received three doses of the HPV-16/18 VLP or Havrix (Hepatitis A) vaccine over a period of six months. At entry and throughout follow-up, women were carefully monitored and received state-of-the-art screening for cervical neoplasia. 

This study was designed to evaluate vaccine efficacy, immunological correlates of long-term vaccine success and failure, and other factors of immunological and etiological interest. Extension of follow-up for up to ten years is now underway to assess the duration of protection and long-term effects of vaccination. Data from the trial demonstrated that three doses of the HPV vaccine may not be necessary, as similar vaccine efficacy against cervical HPV-16/18 infection was observed among women who received two, and even a single dose, of the HPV vaccine after four years of follow-up.

For more information, contact Allan Hildesheim.

Infections and Immunoepidemiology Branch - Research Areas