"She hates them with a passion. We used to have to hold her down," Ms Wallace said, describing a scenario familiar to many parents come vaccination time.

But the purpose of that prick of pain became abundantly clear to 13-year-old Ruby when her mother was diagnosed with cervical cancer.

"She's a lot more willing to get past the needle phobia because she understood the importance of the vaccination," Ms Wallace said.

The PR professional and mother-of-three was diagnosed with stage four cancer in 2015 after a rigmarole of tests and surgeries.

The 44-year-old went through more surgery and four months of chemotherapy, undergoing treatment at Chris O'Brien Lifehouse comprehensive cancer centre.

"I always looked after my health. I was very active, I watched what I ate and always made sure I was getting the right checks. It just shows it's no guarantee you're going to be safe or okay," she said.

Her main concern was her three children, Jack, 17, Ruby and Charlie, 7.

"My focus was being here for my children and making sure they live a healthy, long life," Ms Wallace said.

Now nine months in remission, she's vehemently passionate about improving immunisation rates, in particular the Human Papillomavirus vaccine, which protects against two high-risk HPV types that cause 70 per cent of cervical cancers in women and 90 per cent of all HPV-related cancers in men.

"No one wants their child to go through this," she said.

"We are very fortunate to live where we live, and have access to the a great vaccination program ??? but people do slip through the cracks," she said.

"The preventative is better than the cure," she said.

A group of immunisation experts has warned the gaps in Australia's world-leading school immunisation programs must be plugged to protect all teenagers from vaccine-preventable diseases.

Too many teenagers miss out on crucial doses of life-saving vaccinations when they forget to give their parents the consent form, or don't hand it in, according to a discussion paper published Monday by the Immunisation Coalition.

Others miss out because they're off sick or miss school on vaccination days.

With the introduction of a new Meningococcal W vaccine to the NSW school-based program, and a national working-group set up to investigate how best to combat the rise of meningococcal W strain, it's the ideal time to take stock of the entire school immunisation program, argue the panel of immunisation experts, education group and youth representatives who compiled the report.

The school-based immunisation program is one of the most successful in the world at protecting adolescents from vaccine-preventable diseases, the coalition said.

It also has the highest HPV coverage of any country, and has boosted coverage rates over the last three years.

Full coverage rates among boys has risen from 29 per cent in 2013 to 66 per cent in 2015. Coverage among girls has increased from 71 per cent in 2012 to 77 per cent in 2015.

In NSW, 63.2 per cent of eligible boys received their third dose of the HPV vaccine in 2015, compared to 72.1 per cent in Victoria.

But head of clinical research at the National Centre for Immunisation research and Surveillance (NCIRS) Professor Robert Booy said coverage across for all school-based vaccination rates fell short of the national targets needed to ensure herd immunity.

"It's a real worry that we can achieve 90 per cent vaccination uptake in babies and high levels of individual and herd protection, but only 80 per cent in teens," said Professor Booy, a Board member of Immunisation Coalition.

"Vaccines on shelves are no good to anyone. But put it into someone's arm and it saves lives," Professor Booy said.

The discussion paper put forward six recommendations, including simplifying the consent form process - one of the biggest barriers to improving coverage - pointing to a pilot trial of online consent forms in Queensland.

They also recommended introducing automated reminders for parents (for instance text messages) and alert systems for GPs to follow up on missed doses, better connecting schools with general practices, and improving awareness among families with teenagers.

"Some parents believe that by doing nothing they are keeping their child safe, however the opposite is true," said Immunisation Coalition chairman Professor Paul Van Buynder.

"It is vital for parents to understand and recognise the benefits of teen vaccination," he said.

Matthew Roussis, NSW Youth Parliament Governor elect said knowledge was power when it came to combating the misconceptions about vaccinations.

"Parents and teens need to know about how vaccines work, what they do, and have the support available to them to help address any concerns that they may have," Mr Roussis said.

A spokesperson for the Department of Health said "Health is working closely with relevant partners to investigate and progress many of the initiatives proposed by the Immunisation Coalition".

"A number of recommendations are already in train, including the sharing of information between the Australian Immunisation Register and HPV Register, and provision of nationally consistent communications products. Other measures, such as online consent forms, are under investigation," the statement read.

"The Department continues to investigate options for national collation and reporting of schools based vaccination information that may include involve the whole of life Australian Immunisation Register," the spokesperson said.