According to a Cochrane review that was released recently, the HPV vaccine, that can protect girls and young women from Human Papilloma virus (HPV) can help protect them against cancer of the cervix later in life. The report appears in the latest issue of the Cochrane Database of Systematic Reviews.
The review by Dr. Marc Arbyn of the Unit of Cancer Epidemiology at the Belgian Cancer Centre in Brussels, and colleagues looked at 26 studies to see the effects of HPV vaccination on cervical pre-cancerous lesions. The results revealed that women who were initially negative for hrHPV or HPV 16/18 DNA had a lesser chance of getting these precancerous lesions. Further the vaccine administered to young women and adolescent girls did not cause any serious side effects, miscarriages, stillbirths or abnormalities in the baby.
Dr. Arbyn said that cervical cancer is the fourth most common cancer among women and nearly a million cases are diagnosed each year. Half a million women succumb to this cancer annually, he said.
This review is unique because despite several phase 1 and phase 2 clinical trial reports with HPV, this is the first time that results from all the important studies conducted with HPV vaccine have been combined to come to a systematic conclusion. While each of these studies looked at overlapping end points, this study looked at a comprehensive list of endpoints wrote the researchers. Authors hope that this review would provide “a template for reporting future results of prophylactic vaccination trials according to the different outcomes ... for different exposure groups.”
The authors state that they were specifically looking at protection of the bivalent vaccine targeting HPV 16/18. This strain is responsible for 70 percent of all cervical cancer cases. Another vaccine under their scanner was the quadrivalent vaccine that also protects against HPV infections leading to genital warts.
All in all the review looked at over 73,000 participants. Among the 26 studies, 10 trials looked at the patients for an average of 1.3 to 8 years after vaccination. These checked the patients for cervical intraepithelial neoplasm and adenocarcinoma in-situ (CIN/AIS) – both early cancer stages. These studies were small and conducted for a shorter period of time wrote the researchers.
They noted that when the girls and young women were hrHPV-negative at the start of the study, the vaccine lowered CIN2+ and CIN3+ and reduced risk of AIS with moderate certainty. CIN2+ associated with HPV 16/18 was also reduced with the vaccines. This was however more prominent among women aged 24 years or less. If the vaccines were administered between ages 25 and 45, they noted, the risks of CIN2+ associated with HPV 16/18 and any CIN2+ were similar between vaccinated and non-vaccinated women. They recommend vaccinating girls and women between ages 15 and 26 years for best protection.
The World Health Organization recommends vaccination against HPV for girls as well as boys between ages 9 and 14. These guidelines are similar in most countries. This review looked at effects on young girls and did not explore the protective effects of the vaccine on boys.