The Union government is set to roll out a nationwide single-dose human papillomavirus (HPV) vaccination campaign for 14-year-old girls to reduce India’s high burden of cervical cancer.Almost 90% of all cervical cancers are caused by persistent HPV infection, making it one of the two types of vaccine-preventable cancers (the other is liver cancer). HPV infection is also linked to anal, penile, vaginal, vulvar and throat cancers — the incidence of which is also likely to come down with vaccination. Here’s a look at why the HPV vaccination matters, especially in India.Who can get the shot, and how? HPV is a common, sexually-transmitted infection. Only certain forms of the virus progress to cancer. HPV immunisation in the teenage years — when girls are going through puberty but are not sexually active — results in better and longer immunity. The 90-day vaccination campaign, likely to be rolled out in a matter of days, will be open to all 14-year-old girls in the country. Also read | HPV vaccination protects even unvaccinated women, says Swedish study: AIIMS doctor on why this holds a big lesson for IndiaEligible girls will need to book a slot at government health centres using the vaccine management platform U-win — just like people used Co-Win during the Covid-19 pandemic.Story continues below this adVaccinations will not end after the 90-day period. The programme will continue at health and wellness centres alongside the country’s routine immunisation framework. Girls who keep turning 14 each year will be able to access the shot this way. An estimated 1.15 crore girls turn 14 every year in India.What vaccine is being used?There are at least 14 types of HPV that can potentially cause cancer. Among these, HPV types 16 and 18 are considered to be the most likely to lead to tumour development, causing about 70% of all cervical cancer cases globally. The vaccines work by preventing the entry of two, four or nine of the most common types of HPV. Though India has an indigenously developed HPV vaccine, which will likely be cheaper, the government will use the proven Gardasil by MSD Pharmaceuticals during this phase of immunisation.This is because the Serum Institute of India’s Cervavac is yet to receive WHO approval and the ICMR is still studying its single-dose effectiveness. Story continues below this adOfficials, however, say that the government may switch to Cerevac — which protects against HPV types 16, 18, 6 and 11 — after around two years when approvals will likely be in place. For the current campaign, the GAVI Vaccine Alliance (a global public-private partnership) will provide India 2.6 crore doses that should be sufficient for two years. Of these, one crore doses are already in India, with the rest being delivered through this year and the next.Is a single dose enough?Yes. The WHO Strategic Advisory Group of Experts on Immunization in 2022 recommended a single dose for women up to 20 years and two doses at a six-month interval among women over the age of 21.The advisory group found “strikingly high efficacy” with one dose among children between the ages of nine and 14. “Immunocompromised individuals, including those with HIV, should receive three doses if feasible, and if not at least two doses,” the experts said.Story continues below this adIndia accounts for a fifth of global cervical cancer cases. Within the country, it continues to be the second most common cancer among women, affecting 1.25 lakh and killing 75,000 each year.While earlier evidence has shown that the vaccine is effective at reducing HPV infection and pre-cancerous lesions, studies have since demonstrated that it also reduces the incidence of cancer. A major study evaluating the real-world consequences of the vaccine in Sweden, published in 2020, found that the risk of cervical cancer was 88% lower in women who received their vaccine before the age of 17.Importantly, universal immunisation of girls also reduces the transmission of the infection to boys and protects them from other cancers.Story continues below this adTake the case of Australia that was the first country to introduce HPV vaccination programme in 2007 and later included boys in 2013. Studies have shown that the vaccination campaign reduced the specific HPV types from 22.7% to 1.5% in ten years among young women. It also reduced the incidence of these HPV types from 11.8% to 1.1% during the same period among women over the age of 25 who were not the focus of the vaccination programme.Also read | HPV vaccination and regular screening can prevent cervical cancer: ExpertWhile the incidence of cervical cancer in India has been declining over the years, a drastic drop in numbers will not only bring down the mortality but also free up overburdened doctors and hospitals for the treatment of other cancers.The world’s first HPV vaccine was approved in 2006, with nearly 158 countries introducing an immunisation programme.Is this India’s first HPV immunisation programme?No. States such as Sikkim, Punjab, and Delhi have previously attempted to introduce the vaccine. Story continues below this adSikkim was the first to roll out a state-wide campaign in 2018, achieving more than 95% coverage for two doses.In 2016, Punjab rolled out a vaccination campaign in Mansa and Bhatinda districts that was later expanded to some other high-burden districts. The coverage was over 97% during the initial phase. Delhi also rolled out an HPV vaccination campaign in 2016 from its standalone cancer hospital, Delhi State Cancer Institute. The programme, however, did not pick up pace as it required girls to come to the hospital and seek vaccination.