health & science

HPV vaccine could reduce premature births

A virus vaccine has long-term benefits for recipients beyond reducing cancer, New Zealand research has unexpectedly shown.

The human papilloma virus (HPV) vaccine targets several variants of HPV, including those which have the highest risk of causing cancers, such as cervical cancer. 

Spread by skin contact, HPV affects around 80 percent of the population at some time in their lives, with most cases occurring after sexual activity. In New Zealand, around 50 women die from cervical cancer each year.

The vaccine has been used since around 2008 in many countries, with most vaccination programmes aimed at adolescent girls. At the time, some experts voiced concerns saying the cost-benefit of the vaccine was unknown because the long-term efficacy of was unproven.

Ten years on from the first vaccinations, long-term benefits are being reported. 

Interim results from a Finnish study published in a letter to the editor of the International Journal of Cancer indicate being vaccinated for HPV could remove the risk of HPV-related cancers for at least 10 years.

Another unexpected benefit was discovered by New Zealand researchers: The HPV vaccine could be responsible for lowering the rate of premature births.

A study co-led by Victoria University’s Professor Bev Lawton showed a 13 percent reduction in premature births in women who have been vaccinated, indicating an association with the vaccine and improved birth outcomes.

Lawton said the retrospective study was inspired by New Zealand researchers discovering placenta infected with HPV led to a premature delivery in 25 percent of cases. 

“I said, What would happen if we vaccinate?”

Using data in New Zealand’s national immunisation registry and national health index, Lawton’s team matched HPV vaccination rates with premature birth information.

An estimated 14.9 million infants are born prematurely worldwide and if half of all pregnant women were vaccinated against HPV prior to pregnancy, there could be a reduction of 10 percent in premature births.

The research found receiving more than one vaccine dose prior to pregnancy was associated with a 13 percent reduced likelihood of having a premature birth. 

Around seven percent of live births in New Zealand are premature. The rate for Māori and women over 40 is higher. 

“Even being born a little bit pre-term is associated with cognitive difficulties with the baby as it gets older. Some people do really well with being pre-term and some people don’t. Obviously the more pre-term they are, the difficulties are higher for the baby and the cost is higher for society.”

Lawton said an estimated 14.9 million infants are born prematurely worldwide and if half of all pregnant women were vaccinated against HPV prior to pregnancy, there could be a reduction of 10 percent in premature births.

The next step for Lawton is a new research study including Australian, Swedish and New Zealand databases to look at the questions in a more in-depth way and to duplicate and explain findings.

“We’ve done a big jump from finding HPV in the placenta to - ‘Does the vaccine work?’ If the vaccine works to reduce some of the harm, that is, we think to stop some of the infection in the placenta, then that’s really exciting.”

Barriers to vaccination uptake

Despite research showing long-term benefits of the HPV vaccine, countering misinformation spread by anti-vaccination campaigners can be difficult. 

Information spread on social media incorrectly claims the vaccine is untested, it causes a variety of health issues, and that ‘a lead developer’ the vaccine, Dr Diane Harper, has said the vaccine was ineffective and dangerous.

Harper, who was a researcher, not a developer, of the vaccine has since refuted the reporting of her comments, saying she was misquoted.

In New Zealand, Family First has taken a stance on the vaccine, focusing on the sexual transmission of the virus. They say infection “is not a communicable disease but a consequence of behaviour” and sexual activity of young people, and the need for an HPV vaccine is grossly overestimated. 

“This decade is a decade where we could potentially eliminate cervical cancer and perhaps the other cancers associated with HPV. When you see young people not using a tool that’s available to them, which is the vaccine, they’re missing out on that opportunity.”

- Professor Bev Lawton

The Ministry of Health estimate 24 percent of adolescents are sexually active by the age of 15. The vaccine is most effective if received before sexual activity begins. In an attempt to reach as many adolescents as possible the New Zealand vaccination programme has been administered through schools since 2008. 

The University of Auckland’s Director of Research at the Immunisation Advisory Centre, Dr Helen Petousis-Harris, said schools play a vital role in the immunisation programme as it has made getting the vaccine easy for everyone.

“When you deliver it in a school-based programme you can achieve higher coverage in your most vulnerable groups. Given the highest rates of cervical cancer are with Māori and Pacific women you’ve got the potential to eliminate inequity.”

Anti-vaccination campaigners have targeted schools in an attempt to dissuade them from allowing vaccinations to take place on their grounds.

Gardasil Awareness New Zealand emailed around 2500 schools saying they could face civil action for breaching health and safety obligations by allowing free HPV vaccinations to take place on their grounds. 

While many schools ignored the email, anti-vaccination campaigning did result in at least one school in Timaru removing itself from the vaccination programme.

The South Canterbury DHB where the school pulled out of the vaccination programme has low levels of vaccination uptake compared with other areas in New Zealand. In 2016 the rate of girls born in 2002 consenting to the vaccine was 37 percent, compared with 66 percent nationally. The Ministry of Health target is 75 percent.

Last year, in an attempt to counter misinformation, the DHB turned to social media. This year the efforts to improve vaccination rates are ongoing. Child and Youth Manager, Sarah Greensmith, said the DHB is continuing to try to improve immunisation understanding in its community. Public talks will be held and parents will be encouraged to discuss concerns with public health nurses or their family doctor. 

A national campaign to support the school-based immunisation programme commences this week. The campaign includes online, TV and print advertising as well as local radio. 

Missed opportunity

Lawton hopes the new research into the link between the HPV vaccine and a reduction in premature births could help reduce barriers to vaccine uptake. 

“Parents have some concerns sometimes about HPV being a sexually-transmitted disease, but they can also think about the baby, if we prove this then it will be about the whānau and the baby which to me is important to a lot of families, so it’s a protective thing.”

She is disappointed some young people are missing out on the potential benefits of the vaccine.

“This decade is a decade where we could potentially eliminate cervical cancer and perhaps the other cancers associated with HPV.

“When you see young people not using a tool that’s available to them, which is the vaccine, they’re missing out on that opportunity.”

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