HPV vaccine Cervarix is protective against subtypes

HPV vaccines have been developed from the capsid coat of the virus. It has high immunogenicity. Bivalent vaccine is against HPV 16 & 18. Quadrivalent vaccine is against 16, 18, 6 & 11. Effective in the prevention of 90% of cervical cancer. Both vaccines have some cross-protection against strains 31, 33 & 45. Vaccines are given at an age of 12-18years, safe and well tolerated. Three doses, IM over deltoid muscle. The impact is greatest when given before women are infected with HPV. Vaccine-induced neutralizing antibodies works locally on cervix by preventing attachment of the virus to the cervical epithelium. Immune defense is type specific & is effective only when given prophylactically. Vaccines are effective for at least 7.5years. Pap smear screening should be continued as vaccines are type specific and do not protect all types of HPV. Reference: Dutta's Textbook of Gynecology