This is Riley Hughes. The little boy changing minds about vaccination, even two years after his death.

Catherine Hughes tends to keep memories of her son, Riley, locked away, to protect herself from the grief.

“He was a good little breast feeder, I remember that. And he had beautiful, soft, blonde hair. And his eyes would gaze up at you as you fed him, or cuddled with him,” Catherine told Mamamia.

“And I remember sometimes we’d make the bed in the middle of the afternoon, and we’d have him in there with our daughter, and we’d just have a family snuggle. That was really, really lovely.”

Riley died on March 17, 2015, just one and a half days after being admitted to intensive care with whooping cough.

The Western Australian boy had only entered the world 32 days earlier, but he did so into a family that would turn his short life and their immense pain into a mission to spare others.

The Light for Riley Project and the Immunisation Foundation of Australia now consume the time Catherine and Greg Hughes would have been spending with their son. Whatever spare moments they can find between work and raising their daughters, aged five and one, are spent researching immunisation, tracking statistics and innovations around Australia and the world.

“Obviously we’d do anything we could to have Riley back in our arms,” Catherine said. “But this is the silver lining, this is finding something good in something that was so tragic for our family.”

At just four weeks old, Riley was too young to be vaccinated. A month shy of his early vaccinations due under the National Immunisation Program Schedule, he was vulnerable. When his nose began to run and a little cough started, Catherine and Greg took him to Princess Margaret Hospital in Perth, just in case.

He never left.

"In moments of extreme tragedy or grief, your mind snapshots some of the most inane things," Greg said. "I think back to that time and I can remember the sounds that the machines made, and I can remember the smell of the room, and the layout of the room and everything that was in there. There are elements of it that I try not to think about too much, because if I do I'll go off the deep end. But the intensive care process, I can pretty much recall minute by minute what went down there."

Within days, Riley's condition deteriorated rapidly. Later the couple would share to Facebook a viral video of their son's little chest heaving, struggling to draw air between each racking cough.

"There was an enormous feeling of helplessness, but also a sense of failure," Greg said. "I'm his parent; I'm meant to protect him and look after him, but there was literally nothing I could do. I just had to sit back and watch this insidious disease take its course."

Whooping cough, or pertussis, is a highly contagious respiratory infection spread by coughing or sneezing, or from close contact with an infected person. In a household where someone has whooping cough, an estimated 80-90 percent of the unimmunised household contacts of that person will get the disease.

Pertussis vaccination is  available for free under the National Immunisation Program Schedule at two, four and six months with boosters at 18 months, four years and 10-15 years. While vaccination has dramatically reduced the incidence of whooping cough in Australia, it's still highly dangerous to newborns. About one in 125 infants under the age of six months who contract whooping cough will die as a result.

Catherine and Greg are helping to curb that statistic by campaigning to increase the uptake of the pertussis vaccine, which is available to pregnant women during their third trimester, and protects mum and passes antibodies to the baby via the placenta, which is the most effective way to protect a young baby against pertussis. A free pertussis vaccine during pregnancy is funded in each Australian state and territory, available through GPs and antenatal clinics and in some states other providers.

"I think it's quite natural for mums to worry about what they do during pregnancy, to be scared of something going wrong. Often I speak to women who are a little unsure about whether pregnancy vaccination is the right thing to do," Catherine said.

"The science is clear, vaccines are safe, they are effective. People need to make sure they get their information from a really good, reputable source."

To those parents hesitating or questioning vaccinating their children, Greg Hughes stresses that immunisation is a simple, safe and effective way of protecting individuals against harmful, life-threatening diseases and, in the process, also dramatically reduces transmission among the population.

"You have a responsibility not just to your family, but to the whole community," he said. "We live in a country where no child should be dying from a vaccine-preventable disease and if we could get those rates up to where they need to be, then we'd be helping save the lives of people who can't necessarily be vaccinated."

Knowing they're spreading this message makes dealing with the loss of Riley that little bit easier for the couple.

When it first happened, Catherine said she was left feeling as though her heart had "been ripped into halves, then quarters", like she couldn't breathe, as her brain struggled to comprehend a family and a future without him.

"It's still really raw and it runs really, really deep. But the time in between those patches of grieving gets a little bit longer each time," she said.

Through it all they've had to support their eldest, Olivia, Riley's big sister, his protector.

"One of the hardest things we've ever had to do was explain to her that her brother wasn't coming back from hospital. And to see her little face all crestfallen, and trying to understand the finality of death," said Catherine.

"She handles her grief pretty well," Greg added, "but even now from time to time and we'll catch her a little bit upset or a little bit quiet and she'll say, 'I'm missing my brother'. It's tough."

Catherine and Greg will ensure that Olivia and her little sister, Lucy, talk about their brother, about how they love and miss him, and about how he changed minds and saved lives.

"I've had people coming up to me crying and saying, 'You don't know what your son means to me' and 'Your son has changed my outlook on vaccination' or 'I did everything I did because of your son', and that makes be really proud because, yes, he only lived on this earth for 32 days, but he achieved more than I ever will in my life," Greg said.

"It's an incredible legacy he leaves behind."

Get the facts about immunisation from the Australian Government's Immunisation Facts website.

This content was created with thanks to our brand partner the Australian Government Department of Health.