Cervical Cancer Vaccines May Cut Need for Screening

Two new studies found the Cervarix human papillomavirus vaccine is very effective against cervical intraepithelial neoplasia grade 3+ and adenocarcinoma in situ, and it also cross-protected against cancer-causing HPV types not specifically targeted by the vaccine.

The vaccine was designed to protect against HPV types 16 and 18, which are responsible for about 70 percent of cervical cancer cases. Partial efficacy against other types would extend protection against the HPV strains causing about 85 percent of cervical cancer cases worldwide.

The first study involved almost 20,000 healthy women ages 15-25 from 14 countries. It showed Cervarix gave high rates of protection against high-grade cervical precancers, early development of adenocarcinoma, and 12 other oncogenic HPV types.

“Provided that organized vaccination programs achieve high coverage in early adolescents before sexual debut, HPV vaccination has the potential to substantially reduce the incidence of cervical cancer, probably allowing the modification of screening programs,” said Matti Lehtinen, University of Tampere in Finland, who worked on both studies. “This would certainly mean lots of savings in terms of costs of screening.”

The second Cervarix study showed cross-protective efficacy against cancer-causing HPV types not directly targeted by the vaccine - 31, 33, 45 and 51 - in different groups of women.

“Our results show that cross-protective efficacy might provide substantial protection against cervical cancer,” said Cosette Wheeler, of the University of New Mexico, who co-led the second study.

Increasing vaccine coverage before sexual debut “is now the most important public health issue in HPV vaccination efforts,” Mark Schiffman and Sholom Wachholder, of the US National Cancer Institute, wrote in an accompanying editorial.

The studies, “Overall Efficacy of HPV-16/18 AS04-Adjuvanted Vaccine Against Grade 3 or Greater Cervical Intraepithelial Neoplasia: 4-Year End-of-Study Analysis of the Randomised, Double-Blind PATRICIA Trial” and “Cross-Protective Efficacy of HPV-16/18 AS04-Adjuvanted Vaccine Against Cervical Infection and Precancer Caused by Non-Vaccine Oncogenic HPV Types: 4-Year End-of-Study Analysis of the Randomised, Double-Blind PATRICIA Trial,” and the editorial, “Success of HPV Vaccination Is Now a Matter of Coverage,” were published ahead of the print edition of Lancet Oncology (2011; doi:10.1016/S1470-2045(11)70286-8, doi:10.1016/S1470-2045(11)70287-X and doi:10.1016/S1470-2045(11)70324-2).

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