Global/India Burden of Oropharyngeal Cancers (OPC)
Globally, head and neck cancers are the sixth most common cancer and one of the most common cancers in India. The annual crude incidence rate per 100,000 in India has been reported as 2.4 in males and 0.52 in females. In India, in 2020, there were an estimated 17,175 new cases of OPC in males and 3,442 in females, with 10,367 deaths in males and 2,066 in females. The contribution of HPV to squamous cell carcinoma of head and neck has been rising and presently stands at 47.7% overall and up to 72.2% in oropharyngeal cancers. As compared to HPV-negative head and neck cancers, HPV positive head and neck cancers tend to affect patients who are younger, consume less or no alcohol, and do not smoke. They are generally diagnosed at a higher stage and may have distant metastasis at diagnosis. They have a reasonably good response to the treatment.
A systematic review from India showed the prevalence of HPV in head and neck cancers ranging from 0-86.6% in India. The broad range resulted from the heterogeneity of the data. Data from 3,847 patients of head and neck cancer patients showed that 1,110 patients were HPV positive, implying a cumulative prevalence of HPV positive head and neck cancers in India around 28.85%. There was no difference in treatment outcome among HPV positive and HPV negative cancer patients.
Global/India Burden of Anal Cancers
HPV related cancers also include anal cancers with approximately 90% of anal cancers being related to HPV. In the meta-analysis study carried out by De Sanjose et al in 2019, HPV16 was present in 80.7% of anal cancers. Worldwide, in 2020, there were an estimated 29,159 cases of anal cancer in women with an age-standardized rate (ASR) of 0.58/100,000 and 21,706 cases of anal cancer in men with an ASR of 0.49/100,000. There were an estimated 9,877 deaths in women and 9,416 deaths in men. Estimated figures for India were, 3,111 cases in males and 2,341 in females, with an estimated 1,560 deaths in males and 1,216 deaths in females. In a study done from two major cities in India, the prevalence of anal HPV was 95% (95% CI 91%-97%) in men who have sex with men (MSM). Among the women living with HIV from India, the anal HPV prevalence was 14.3% and high-risk HPV prevalence was 9.2%.
Global/India Burden of Penile Cancers
Worldwide, in 2020, there were an estimated 36,068 cases of penile cancers (PeCa), with 13,211 deaths. The estimated burden in India was 10,677 cases and 4,760 deaths, with an estimated age-standardized incidence of 0.84 cases per 100,000 person-years. In a single center analysis of 40 cases from India, the overall prevalence of HPV in PeCa was 42.5% as compared to 20% in controls. Among the subtypes, the most common subtype was HPV 16 noted in 33.3% of cases followed by HPV 18 in 29.2% of cases.
HPV immunization in Male Population
- Above mentioned data support the use of HPV vaccines in males. To date, 125 countries have introduced HPV vaccine in their national immunization program for girls, and 47 countries also recommend HPV vaccination for boys
IAP-ACVIP Recommendation
- Due to the significant burden of HPV related cancers and other conditions, the IAP-ACVIP recommends the use of HPV vaccines in boys.
- All currently licensed HPV vaccines, including 9vHPV vaccines have excellent safety profiles and are highly efficacious, or have met immune bridging standards in both male and female. 9v HPV Vaccine is recommended in a 2-dose schedule with an interval of six months, for boys and girls between 9 to 14 y. This schedule also has cost-saving and programmatic advantages that may facilitate high coverage. The 3-dose schedule of the 9vHPV vaccine is recommended for females, when the schedule is initiated after 15 years of age.
Injectable Polio Vaccine
Guidance on Changeover from NIP to IAP Schedule
The IAP-ACVIP recommends five doses of full-dose (0.5 mL) intramuscular (IM) inactivated polio vaccine (IPV), including three primary doses at 6wk, 10wk and 14wk and two booster doses at 16-18 mo and 4-6 y. The National Immunization Programme (NIP) recommends 3 doses of fractional-dose (0.1 mL) inactivated polio vaccine (fIPV) at 6 wk-14wk-9mo given intradermally (ID), along with bivalent oral polio vaccine (bOPV), 2 drops, at 6w-10w14w and 16-18 mo. It is not uncommon for a changeover from the NIP to the IAP schedule after 6 months of age as the NIP does not provide for many of the vaccines recommended by IAP for infants beyond 6 months of age. For this reason, guidance is being issued regarding use of IPV in children shifting from the NIP to the IAP schedule. Following 2 doses of fIPV at 6wk-14wk, the IAPACVIP recommended an additional dose of full dose IMIPV at least 8 wk after the last dose of fIPV. This recommendation was made as 2 doses of fIPV at 6wk14wk resulted in seroconversion of 82-85% against type 2.
It was expected that an additional dose of IM-IPV will increase the seroconversion rates to a much higher level. The NIP now recommends 3 doses of fIPV at 6wk-14wk9mo, with the 9 mo dose being a booster dose. There is no substantial difference in seroconversion rates between 2 and 3 doses of ID fIPV, and 2 and 3 doses of full-dose IM-IPV, although the full dose gives higher titres of antibodies for poliovirus type 1, 2, and 3. A 2-dose schedule of IPV at 14w and 36w resulted in seroconversion rates of 96%, 98% and 85%, for serotypes 1, 2 and 3 respectively, by the intradermal route and 99%, 99% and 97% by the IM route. Hence, any additional benefit from an additional dose of IM-IPV, will be of marginal benefit only. Two doses of fIPV administered at 14wk and 36wk resulted in higher seroconversion rates compared to an earlier schedule of 6wk and 14wk, for all serotypes: fIPV 96%, 98%, 85% (14 wk and 36 wk); 83%, 84%, 83% (6 wk and 14 wk).
IAP-ACVIP Recommendations for IPV
- For infants who have received the 3-dose fIPV as per the NIP, an additional dose of IM-IPV is not necessary at 16-18 mo.
- A booster of IM-IPV is recommended at 4-6 y. The rationale for a booster at 4-6 y has been published earlier.
