A common viral infection of the reproductive tract, Human Papillomavirus (HPV), is transmitted through sexual contact. Most people are infected with HPV after sexual activity. While there are 100 variations of HPV, of which nearly 15 variations can cause cancer, others are a low-risk variety that generally causes warts on or around the genitals and anus of both men and women.
When it comes to variations of HPV, HPV 16 is most associated and present in more than 80 per cent of high-grade cervical, vaginal, vulvar, perianal, and penile preinvasive lesions. It has been detected in more than 25 per cent of low-grade cervical lesions, 40 per cent of subclinical vulvar HPV infections, and ten per cent of genital condylomata acuminate.
The second most common HPV type is HPV 18 (25 per cent) and is seen in invasive cervical cancer but is uncommon (five per cent) in pre-invasive cervical lesions.
The association of HPV 18, particularly in younger women, and the underrepresentation of this viral type in preinvasive lesions have raised concerns in the medical community that HPV18 may be associated with ‘rapid-transit’ cancers that escape reliable cytologic detection.
Since HPV is linked to cervical cancer, raising awareness about its vaccine is essential, especially among young girls and parents. According to the National Cancer Registry of India, cervical cancer is the second most common cancer in females, with a cumulative risk of 1 in 75 females. To reduce this risk and raise awareness for cervical cancer, HPV vaccination and screening of the virus among the vulnerable population plays a vital role.
Early detection and treatment of cervical cancer can prevent up to 80 per cent of causalities caused by the disease. Also, the high mortality rate from cervical cancer worldwide can be effectively reduced by primary prevention methods like HPV vaccination and secondary prevention tactics like effective screening and treatment programmes.
According to the World Health Organization (WHO), vaccination against HPV in girls must be done between 9-13 years, although it is commonly given to women at the age of eleven. The optimal vaccination schedule is two doses at zero and six months. After a girl turns 15, the recommended vaccination schedule is three doses at zero, two and six months. If the dosing schedule is interrupted, the previous vaccine does not need to be repeated and the next dose should be given at the earliest possible time.
There are three different types of HPV vaccines globally, although only two are available in India. They both protect against HPV 16 and 18, which is responsible for almost 70 per cent of cervical cancer cases. The three vaccines against HPV are listed below.
Quadrivalent vaccine (Gardasil) - against types 16 and 18 (high risk) and types 6 and 11 (low risk)
Bivalent vaccine (Cervarix) - against types 16 and 18 (high risk)
Polyvalent vaccine (Gardasil -9) – against types 6,11,16,18,31,33,45,52 & 58. (Not available in India)
Clinical trials of the vaccines have shown that they are safe and relatively effective in preventing HPV and cervical cancer. These vaccines work best if they are administered before exposure to the virus, so they should be issued before sexual activity. Further, the three doses of the Quadrivalent vaccine may also be administered to males, starting from the age of nine. These vaccines will go a long way in reducing the cases of genital warts and anorectal cancer while preventing cervical cancer in their partner. Also, the vaccine can be administered till the age of 26 in males to reduce their likelihood of acquiring genital warts.
In conclusion, cervical cancer is preventable, and the HPV vaccine is an effective tool to help make this possible. Therefore, it is the responsibility of the parents, caregivers and healthcare staff to promote awareness of this vaccine and its importance among the general public.
(Dr. Harshit Shah is Surgical oncologist, Associate Consultant, Fortis Hospitals, Mulund & Kalyan)
