HPV Vaccination Cuts Cervical Cancer Cases by Nearly 90%: Study

Almost all cervical cancers are caused by the human papillomavirus (HPV), but it is also one of the few cancers that can be prevented by a vaccine. Now real-world data from a UK HPV vaccine program has revealed that vaccination reduced the number of cervical cancer cases by nearly 90%. 

UK HPV Vaccine Program

The study began in 2008 and followed women who were offered the HPV vaccine at ages 12 to 13, when exposure to the virus was unlikely. 

Scientists from King’s College London, the UK Health Security Agency (UKHSA) and the National Cancer Registration Analysis Service (NCRAS) worked together to complete the study, the results of which were published in The Lancet on Wednesday. 

The researchers found that over an 11 year period, the UK HPV vaccine program reduced cervical cancer rates by 87%, and in combination with screening could almost completely prevent cervical cancer from developing. 

In particular, the vaccine lowered cervical cancer incidence by 34% if given at ages 16 to 18, by 62% if given at ages 14 to 16 and by 90% if given at ages 12 to 13. 

The team estimated that the program has prevented around 450 cancers and 17,200 precancerous conditions over its duration. 

“It’s a historic moment to see the first study showing that the HPV vaccine has and will continue to protect thousands of women from developing cervical cancer,” said Michelle Mitchell, Cancer Research UK’s chief executive.

Professor Peter Sasieni, lead author from King’s College London, says: “It’s been incredible to see the impact of HPV vaccination, and now we can prove it prevented hundreds of women from developing cancer in England. We’ve known for many years that HPV vaccination is very effective in preventing particular strains of the virus, but to see the real-life impact of the vaccine has been truly rewarding.

HPV, A Common STI

HPV is one of the most common sexually transmitted infections (STIs), and affects both women and men. In 2018, it was estimated that 570,000 women and 60,000 men were diagnosed with cancer attributed to HPV infection.  

There are over 100 strains of virus, of which two strains HPV 16 and 18 account for around 70% of cervical cancer cases. 

The virus is commonly spread via sexual contact, but non-sexual contact such as sharing bath towels with an infected person still carries the risk of infection. In most cases, symptoms do not surface and the body’s immune response clears the virus within two years.

Symptoms that do surface may include genital warts or cellular changes which lead to cervical cancer. 

HPV Vaccines 

A variety of multivalent HPV vaccines have been developed to counter infection, multivalent meaning it takes effect against multiple strains of virus. 

One of the first HPV vaccines to be approved is Cervarix, developed by GlaxoSmithKline. It was also the vaccine used in the UK HPV vaccine program. Cervarix protects the body against HPV 16 and 18 by using a viral protein found on the virus to stimulate the immune response. 

While proven effective in the program, the UK government has since replaced GSK’s shot with Merck’s Gardasil. The switch, which took place in September 2012, has been attributed to Gardasil’s efficacy against HPV 6 and 11 in addition to HPV 16 and 18. 

Gardasil’s lead over Cervarix became more pronounced after GSK pulled out of the US market in 2016, citing lack of demand. 

Merck soon developed a nine-valent vaccine called Gardasil 9. In addition to guarding against the same strains as its predecessor, Gardasil 9 guards against high-risk strains HPV 31, 33, 45, 52, 58. It is the main HPV vaccine given in the US. 

Meanwhile, another vaccine, Cecolin, has been developed by China’s Innovax and approved by the country’s drug regulatory body since 2019. The bivalent vaccine is effective against HPV 16 and 18, and is being positioned as a cheaper local alternative to Cervarix, Gardasil and Gardasil 9. 

Author

Joy Lin

Without knowledge, there is no imagination. Without imagination, knowledge is meaningless