Study backs Kenya's plan to vaccinate boys against HPV

Kenya’s plan to vaccinate school boys against HPV has received more backing from a World Health Organization-backed study that shows one in three men over 15 years are infected with the virus.

These estimates, published in The Lancet Global Health, emphasise the importance of incorporating men in efforts to control HPV infection, WHO said in a statement.

“Human Papillomavirus (HPV) is the leading cause of cervical cancer in women and each year more than 340,000 women die of cervical cancer related to HPV.  In men… HPV related cancers in men include penile, anal, oral and throat cancers,” WHO said.

A systematic review of studies from 1995 to 2022 in 35 countries was conducted to assess the prevalence of genital HPV infection in the general male population.

The findings revealed almost one in three men above 15 years are infected with at least one HPV type and one in five are infected with one or more of the high-risk, cancer-causing HPV types.

“These estimates emphasise the importance of incorporating men in comprehensive HPV prevention strategies to reduce HPV-related morbidity and mortality in men and ultimately achieve elimination of cervical cancer and other HPV-related diseases,” said authors of the study, titled “Global and regional estimates of genital human papillomavirus prevalence among men: a systematic review and meta-analysis.”

Each year about 3,200 Kenyan women die of cervical cancer related to HPV.  In men, WHO estimated that in 2018 there were more than 69,400 of cases of cancer caused by HPV, globally. 

HPV-related cancers in men include penile, anal, oral and throat cancers. Complete figures for Kenya are not available.

Kenya’s Ministry of Health announced in February that boys in primary school would soon be eligible to receive the free HPV vaccine.

The HPV vaccine is currently only given to girls, aged nine to 14 years.

Dr Mary Nyangasi, head of the National Cancer Control Programme in Kenya, said because HPV is sexually transmitted, reducing the number of males carrying the virus will help prevent its transmission to women.

“Initially we targeted only nine-year-old girls because the doses we received were very few, so you have to give it to the people who will most need it and those were girls who were nine years,” she said in Nairobi.

“We managed to negotiate, now we are able to get doses that can reach nine to 14-year-olds.”

She said once the ministry has enough stock of the vaccine, this year, it will begin enrolling boys.

“We are still negotiating for more doses, the world is moving towards vaccinating all boys and girls between nine to 14 years,” she said.

Dr Nyangasi said Kenya’s goal is to vaccinate all boys and girls aged nine to 14 years.

Currently, 60 per cent of all eligible girls have received the first of the recommended two doses.

The vaccination provides protection against HPV types 16 and 18 which are responsible for approximately 70 per cent of cervical cancer cases.

The vaccine also prevents boys from getting infected with the HPV types that can cause cancers of the mouth or throat, penis and anus as well as genital warts.

The optimal age of vaccination is in the early adolescent period, before sexual debut with possible HPV infection.

However, last year, the World Health Organization released new guidelines showing one dose is actually enough and children do not need a second one.

Prof Nelly Mugo, head of the Sexual Reproductive Adolescent Child Health Research Programme at the Kenya Medical Research Institute (Kemri), said Kenyan scientists also conducted a trial that proved one dose is enough to protect from HPV infection.

“In the trial, we vaccinated girls who were aged 15 to 20, sexually active, with one dose. We have data on follow-up for the first 18 months and for five years, for girls who were vaccinated and did not initially have HPV. None of them got any HPV,” she said.

Only the Gardasil HPV vaccine, which is licensed in Kenya, is recommended for boys.

The vaccine can be given as early as age nine and is also approved for adults up to age 45.

The National Cancer Institute says in Kenya the most common cancers among men are the prostate followed by the oesophagus and colorectal (23.7 per cent, 15.9 per cent and 8.8 per cent respectively).

The most common for women are breast followed by cervix and oesophagus (26.5 per cent, 23.2 per cent and 8.8 per cent respectively).

Most cases of oesophagus cancer are caused by HPV.