Professor John Dwyer. ''Our little daughter, Ashleigh, contracted pneumococcal meningitis at age six months back in 1989. PM is now a vaccine preventable disease. It wasn't then.'' Langoulant is the full-time carer of his now-24-year-old daughter who has never walked or talked, suffers from cerebral palsy, epilepsy, is profoundly deaf, and has the intellectual capacity of a two-year-old, at best. He has spent a full career spreading awareness of the disease that changed the life of his child within 24 hours. ''I witnessed the introduction of the Hib vaccine for Hib meningitis in '93 when it was causing 40 per cent of meningitis cases in Australia,'' he says. ''I subsequently saw it drop to zero or one. We're talking about in Western Australia, we had about one to 1½ cases a week - now you'd be lucky to see one a year.''

Professor Mark Ferson. Credit:Adam McLean For all of Bruce Langoulant's efforts to advocate for the now widely available vaccine, there is a community, just as vocal, undermining and condemning the vaccination campaign. Google the word ''vaccination'' and the first entry that comes up after Wikipedia is The Australian Vaccination Network (AVN), a staunchly anti-vaccination website. Photo: Getty Images ''Because every issue has two sides,'' says the AVN website's banner.

This is a worry for pro-vaccination campaigners such as Professor Peter McIntyre, paediatric specialist and Director of the National Centre for Immunisation Research and Surveillance (NCIRS), who analysed the website for the NSW Fair Trading inquiry into whether the AVN's name was misleading. ''If you're coming to it as someone who doesn't have an extensive background in it [vaccination] and just looking for information, then you are being driven down the super highway of garbage information,'' he says. McIntyre is concerned about the way the website presents itself as providing unbiased, objective information. ''It presents itself as presenting both sides of the story but in reality the way it's presented sets out to de-emphasise the severity of the diseases and the effectiveness of the vaccines and seeks to greatly over emphasise and selectively quote, and, in some cases, deliberately misleadingly quote information about adverse effects of vaccines; and relies on anecdote and relies on very ill-founded comments they pick up from particular individuals without giving a sense of what the body of opinion out there is.'' Greg Beattie, president of the AVN, claims his organisation exists to help people in their search for information.

''The AVN is concerned that the information that matters to parents isn't all available for them,'' he says. Beattie is confident that his organisation's information is reliable and accurate. ''All in all, in the AVN resources, you'll see a gigantic amount of resources,'' he says. ''Everyone needs to acknowledge that we need to get rid of that silly story, that vaccinations came along like a white knight and slew the dragon. Vaccination did nothing of the sort.'' Expert immunologist John Dwyer, Emeritus Professor of Medicine at the University of NSW, begs to differ.

''I would say, without hesitation, that the single most useful technique developed by modern medicine, that has done more good for more people, is immunisation or vaccination,'' he says. ''We know the immune system is made up of soldiers that are sitting there waiting to respond to anything that comes in via our body.'' Dwyer explains these soldiers will stand to attention when a small amount of a controlled, harmless virus is introduced - the vaccine - and multiply their forces so that if that virus ever enters the body a second time, the person will be protected or have a less severe infection. ''Now that technology and that approach has been unbelievably successful in saving millions of lives,'' he says. AVN's insistence that vaccines are hazardous and the negative effects outweigh the benefits is dismissed by Dwyer as naive and dangerous.

''There's always been a very small undercurrent of people who've said it's better to let nature take its course, let the kid get infected and become immune, these aren't serious diseases, etc, etc. Those people have never seen a baby dying in terrible distress from whooping cough.'' Dwyer says that, while some children are legitimately unable to be vaccinated for medical reasons, and others will be between doses, they can still be protected in a community with high immunisation rates. This is called ''herd immunity''. ''If everybody was immunised, there's no hope, no place to hide for the virus and it is possible, like we've done with smallpox, to completely eradicate the virus because it had no room left,'' he says. Medical experts believe the AVN's campaign to influence parents' decisions to become vaccine refusers could damage that shield of herd immunity. This could also mean the resurgence of eradicated diseases. ''They're [the AVN] dangerous because, to start with, the adherence to the rubbish they put out,'' Dwyer says.

''Parents are not going to immunise their children, and that's going to put their children at risk. And if enough of them do that, then they will put all children at risk. ''The UK have had a recent experience where the incidence of measles skyrocketed and reminded us of just how dangerous this can be. There were deaths, children died … immunisation rates really fell … because of the scare tactics of anti-vaccination groups,'' said Dr Dwyer. Stephanie Messenger, the author of the children's book Melanie's Marvelous Measles, promoted on the AVN website, is concerned that the public are being misled by medical professionals. ''They are trying to say that vaccination is safe and effective and it is neither one of those things.'' Professor Mark Ferson, director and Public Health Officer of South Eastern Sydney Local Health District, sympathises with the way some parents may have been deterred by the paternalistic approach of the past.

''Perhaps in the past we weren't so good at making things transparent to people that vaccines aren't perfect … We're in the process of being clearer about that - these are the side effects that can happen - and making them publicly available.'' Messenger's book pushes a view that children can be protected from infectious diseases through a healthy lifestyle, and that if they do catch an infectious disease such as measles, they can treat it through natural eating. She emphasises eating foods high in beta carotene to aid the body in production of vitamin A, which she says can fight measles. ''Other things you can do for measles are stay out of sunlight for a certain amount of time, rest up and drink plenty of water. Things like that,'' she says. Messenger is quick to defend her book from the criticisms of people in the mainstream medical world such as Steve Hambleton, President of the Australian Medical Association, who recommended it be withdrawn from sale. McIntyre warns against the approach promoted by Messenger as being inadequate and dangerous.

''It's perfectly possible for people, who as far as we can tell, [are] perfectly healthy, to get severe measles and particularly develop brain inflammation, which is often fatal, and if it's not fatal, may leave you with long-term damage. Sure the chances of that happening are low, but they can be reduced to pretty much zero by being vaccinated.'' One of the main arguments of the AVN and its advocates is that vaccination did not lead to the decline and eradication of infectious diseases like polio or measles in Australia, and smallpox worldwide. ''There is no scientific evidence that is true, it is a belief, it is a myth,'' says Messenger. They say that the decline in deaths occurred before the introduction of vaccines. Greg Beattie further explains the AVN position: ''The reason for these declines is generally improvement in living conditions, sanitation, nutrition, clean water, improved education and improved wealth in general. There's one thing that everyone knows for sure, without doubt, because it's not debatable, and that is, that vaccination was not the magic bullet that came along and did that.''

McIntyre agrees on one thing: that the effects of vaccines are not debatable. He explains that it's certainly true that deaths from measles started to decline before the introduction of the vaccine, due to improved sanitation, healthcare and the available antibiotics. But this is because deaths were occurring due to secondary infections and complications from measles, such as pneumonia, which can be treated with improved sanitation and modern healthcare. But what these treatments and living conditions cannot treat or prevent is the more serious complications: ''In the case of measles, a hard-core complication such as encephalitis, which is inflammation of the brain; and a very scary thing called SSPE, which stands for Subacute Sclerosing Panencephalitis.'' McIntyre describes SSPE as a dormant virus infection that lives in the brain. ''The measles virus sort of sits latent in your brain, and then maybe 10 or 20 years later, reactivates and basically you become a vegetable and die within 12 months,'' he says. ''There's no treatment that will make any sort of difference to that. The only way to prevent those causes of death through measles, is to be vaccinated.''

One of the main concerns the AVN voices is the hypothesised link between the measles, mumps and rubella (MMR) vaccine and autism. This is based on a paper by Andrew Wakefield in 1998, now discredited as fraudulent. Wakefield's medical licence was revoked in 2010 for showing ''callous disregard'' for children's welfare. Both Messenger and Beattie reject the findings of a worldwide accredited 2002 study that researched half a million children and found no link between the MMR vaccine and autism. For Bruce Langoulant, who is also a member of the Disabilities Service Commission in Perth, the matter is cut and dried. He worries that if more parents pay attention to the likes of AVN and don't vaccinate their children and the government doesn't step in, there could be unprecedented consequences. ''If you left it up to the people, the health system could be in a chaotic position; there could be a lot of people on the disability system in a far worse situation,'' Langoulant says. He says recent government moves to prevent entry to preschools for unvaccinated children, and the cut to the family tax benefit for parents who fail to immunise their children, could help combat falling immunisation rates but would need to be implemented hand-in-hand with an education program.

''So you basically give people a heads-up. 'We'll be introducing this, and this is why.' Because it needs to be balanced,'' he says. ''You don't have time to muck around with this disease and your kids deserve the protection you got as a child … I think it's been forgotten and [people think it's] all about lifestyle now. ''Well how about I trade you my lifestyle?'' he asks. ''Since we've introduced these vaccines for meningitis particularly, there's a whole heap of Australian families who don't know how lucky they are.''