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Yale Emerging Infections Program Selected to Monitor Impact of HPV Vaccine

Linda Niccolai, Ph.D., assistant professor in the Division of Epidemiology of Microbial Diseases, is project director of the HPV vaccine monitoring project, funded by the Centers for Disease Control and Prevention

The Yale Office of the Connecticut Emerging Infections Program has been selected by the Centers for Disease Control and Prevention (CDC) as one of 4 sites in 4 states to conduct population-based monitoring to identify early impact of vaccination against the human papillomavirus (HPV).  The project is expected to last for at least five years.

Linda M. Niccolai, Ph.D., is project director of the monitoring project. “Demonstrating the vaccine’s effectiveness in reducing negative health consequences can be used as support for expanding its use, and for making structural and financial policy changes that will increase accessibility for those who want it,” said Niccolai, an assistant professor at Yale School of Public Health.

HPV, a known cause of genital warts and cervical cancer, is the most common sexually transmitted infection in the United States.  Over 20 million people are currently infected by the virus and an estimated 6.2 million new infections are diagnosed each year.  While most HPV infections are cleared by the immune system, 16 of the more than 30 known sexually transmitted strains of HPV are considered high-risk types that are linked to cervical cancer.  According to the CDC, each year 9,710 new cases of cervical cancer will be diagnosed and approximately 3,700 women will die from cervical cancer.

In 2006, an HPV vaccine, GARDASILTM, manufactured by Merck and Co., Inc., was licensed for use among females ages 9-26 for the prevention of HPV-related cervical cancer, cervical cancer precursors, vaginal and vulvar cancer precursors, and anogenital warts.  The vaccine was developed to fight four strains of HPV, types 6, 11, 16 and 18.  The CDC has identified types 16 and 18 as being responsible for 70% of all cervical cancer while types 6 and 11 are responsible for 90% of genital warts cases.

“Though we currently expect to see the greatest impact among young women age 9-26 for whom the vaccine is indicated, over time we also expect to see effects for women over 26 years of age, as those who were vaccinated between ages 9-26 move into older age groups.”  As more women are protected by the vaccine, transmission to male sex partners will decrease reducing the overall burden in the population, potentially producing even greater effects for all women, noted Niccolai.

“The goal of the project is to monitor for changes in the rates of occurrence of the pre-cancerous lesions (CIN2/3) that precede the appearance of cancer as the use of HPV vaccine becomes more widespread,” said James Meek, Associate Director of the Emerging Infections Program (EIP).  Another goal of the project is to monitor changes in infecting HPV serotypes.  As the frequency of the serotypes in the vaccine decreases, it will be important to know if other types that are now less common but also oncogenic increase in frequency.

The primary responsibility for conducting the CIN2/3 monitoring project in Connecticut resides at the Yale EIP office.  The Yale EIP will be working with pathology laboratories and care providers to establish an active surveillance system to identify all cases of CIN2/3 diagnosed in women who are residents of New Haven County. Additional data will be collected through chart reviews and patient interviews to gather demographic and epidemiologic information and to determine if the patients had received the HPV vaccine. 

 “Randomized controlled trials have shown its efficacy in study subjects,” said Niccolai. “Now that the vaccine is being used outside of a clinical trial, we need to show its effectiveness in improving the health of broader populations.”

The Emerging Infections Programs are unique collaborations between CDC, state health departments and academic research institutions in 9 states.  In Connecticut, the EIP is a joint effort between the CT Department of Public Health (DPH) and Yale School of Public Health (YSPH), with principal investigators including Dr. James Hadler at CT DPH and Dr. Robert Heimer at YSPH. Collaborating institutions involved in the CIN2/3 monitoring project include state health departments in California, New York and Tennessee and the University of Rochester and Vanderbilt University.