Hannah McGowan once believed that vaccination was to blame for her chronic health issues, and refused to vaccinate her two young sons. Then, slowly, she started to change her mind.

In 1999 I was 19 and utterly convinced that vaccines had given me Crohn’s disease. Crohn’s is a living nightmare, the kind of hell you wouldn’t wish on your worst enemy. Already hostile and distrustful of the medical profession after many unpleasant experiences, I stumbled across a small study that connected Crohn’s to exposure to the MMR vaccine.

I was hooked. It made sense to me that a medication designed to stimulate your immune system could in turn cause Crohn’s disease, an autoimmune disorder. Medicines I had been assured would help me had already hurt me. I didn’t trust pharmaceuticals. Why should I trust vaccines?

Unable to find a GP willing or able to talk with me in length about my concerns, I went online. I came across terms like ‘big pharma’ and ‘vaccine injury’, terrifying reports from devastated parents convinced vaccines had harmed their children. Studies, blogs and articles published in medical journals reinforced my suspicions. They all seemed legitimate, convincing. I soon became wary of evidence that opposed my newly formed beliefs. I leapt at the chance to share new evidence that supported ‘the cause’, regardless of the authenticity or source, and only if it confirmed my viewpoint.

I became active on anti-vaxx Facebook groups. I met others who had experienced trauma, incompetence, disability, even death after interactions with our health system. We couldn’t rely on conventional medicine but we could rely on each other. We were all hurt, in pain, and angry in the same way. Our pain bonded us. We clung to our truth, to our feelings, to what we knew. We lost the ability to separate facts from falsehoods. We were scared – and when you’re scared it’s much easier for lies to gain traction.

Once a belief has taken hold in your mind, it’s hard to budge it. New information that conflicts with an existing belief causes psychological discomfort, and our brains tend to try to protect us from this by shutting down. It’s called cognitive dissonance – the frustratingly counter-intuitive thing our brains do to ‘protect’ us. It’s this mental phenomenon which gets us caught up in a belief while becoming intolerant to anything that might contradict it.

Cognitive dissonance makes life less challenging. It makes it easy to stay set in your ways. But it’s a lazy way to live: instead of looking objectively at opposing studies you can write them off as the work of ‘big pharma shills’ and remain comfortably certain of your beliefs. I wasn’t able to accept the cost of my decision to not vaccinate. When the danger I was putting my children and others in was pointed out to me, I always found a way to rebuff the evidence and justify myself. My psyche couldn’t handle confronting the reality of my actions.

The love we have for our children and the desire to protect them is a powerful force. A belief that vaccines are dangerous can be so strong that it can blind us with emotion, overriding the ability to be objective or rational. We even find ways to justify the unassailable fact that dangerous, disabling diseases are resurfacing because of our fear.

When British doctor Andrew Wakefield’s autism study claiming a link between the MMR vaccine, autism and bowel disease started to garner serious criticism my brain refused to accept the fact. I was experiencing cognitive dissonance. I began to debate vaccination supporters on open forums, and did some fact checking to defend my side of the argument. It was then that it began to dawn on me that the evidence against Wakefield’s claim was painfully solid. The idea of having to both re-examine my beliefs and very likely alienate people I cared about was a bitter pill to swallow. I didn’t do anything, but my confidence in the dangers of vaccines was crumbling. Were vaccines really the enemy we thought they were? Was any of this fear rational?

About three years ago I had a conversation with someone I respect a great deal. I brought up the fact I hadn’t vaccinated my children and told her I was concerned about the connection between vaccines, Crohn’s disease and immune disorders. I mentioned reports of neurological damage due to severe reactions to vaccines and the possible under-reporting of vaccine related injuries.

We had a discussion about her perspective on vaccination as a member of the DHB and discussed the findings of her colleague, an immunisation specialist. She had a lot of faith in the system and I had a lot of faith in her, but I also had a lot of questions. Her answers were fact-based, scientific and validated by decades of study and testing. I realised that a great deal of the information I had accumulated was outdated, exaggerated, or incorrect.

Finally, I was able to accept that I might want to reevaluate my anti-vaxx views. I began visiting sites I had previously dismissed as biased contributors to the vaccine conspiracy. I soon unearthed the study claiming a connection between the MMR vaccine and Crohn’s disease, and found that it had been discredited the same year I decided to believe it was true.

It became evident that vaccines are constantly under scrutiny, monitored and improved even as a precautionary measure. Deaths related to vaccinations are almost non-existent. So few deaths can be plausibly attributed to vaccines that it is hard to statistically access the risk.

The public demand for absolute transparency has made vaccines one of the safest medical products in use today. Contrary to widespread belief, the vaccine industry isn’t highly profitable. It continues to exist because it is a cost-effective way of reducing death and disablement from preventable diseases, saving $295 billion in direct costs and $1.38 trillion in total societal costs between 1994 and 2013 in the US.

One of the hardest things for me to accept was that the majority of reported ‘vaccine injury’ cases are not supported by evidence. I do not dispute that genuine vaccine injury cases occur. These terrible, life-changing events inflicted on the unlucky few are heartbreaking and justify sincere concern and investigation regarding the safety of vaccines. But amplifying the pain of these events scares others into making choices that will guarantee other parents will know the horror of death or disablement by preventable disease. Vaccine injury cases are statistically unlikely but they are treated as though they are commonplace, and that just isn’t true.

It is incredibly difficult for anyone to cope with an illness or disability that comes on suddenly, especially if there is no clear cause. If a vaccination appears to precede a health crisis or sudden death, it is understandable that people will blame the one known factor. But those who blame vaccinations tend to ignore other, far greater factors like human error or pre-existing conditions.

My research revealed a conclusion I long considered impossible: vaccinations are overwhelmingly safe. It seems counter-intuitive to give healthy people an injection, but herd immunity only works when every healthy, able-bodied individual and child gets on board.

Vaccinating as many people as possible is the only way we can protect our most vulnerable including children too young to be immunised, chemotherapy patients and the elderly.

My response to a more complete understanding of vaccines? I began the belated process of fully vaccinating my children. They didn’t develop Crohn’s disease and they are protected from many dangerous preventable diseases including the ongoing measles outbreak. They are also protected from spreading these diseases and infecting others.

Admitting that I had been wrong was rough. I’d been incredibly lucky – herd immunity had protected my sons – but I had been so afraid of my children suffering that I had willingly put their health and the health of others at risk by cherry picking my way through ‘scientific’ studies and anecdotal reports. Not a fun thing to admit to yourself, let alone others.

I can understand why parents and caregivers are reluctant to begin the long and possibly thankless process of re-educating ourselves. But there is simply not enough real, substantive evidence to justify the war on vaccinations.

Vaccines prevented at least 10 million deaths between 2010 and 2015. Sadly, there are still more than 3 million vaccine-preventable deaths each year in the world, approximately half of which are children under five years old.

Sharing misinformation and clickbait articles leads to more people being afraid to vaccinate, which results in deadly outbreaks of preventable diseases like whooping cough, measles and influenza – all far more dangerous than any vaccine. If you choose not to vaccinate your child and encourage others to do the same, you are at the very least putting the vulnerable in harm’s way.

If you’re an anti-vaxxer, you might have become one because you have an open mind. You can consider different perspectives, possibly more so than most. Please continue to use that open mind to consider new evidence. All of us need to examine a different perspective every now and again. When I began to change my point of view it improved the life of my children, myself, and this tribe we call humanity. It wasn’t easy, but I highly recommend it.

Read more:

Should you vaccinate your child? A guide for parents

Sāmoa is deep in a measles crisis. The last thing it needs is misinformation

Vaccination: A brief and sadly necessary history of its life-saving powers