The outbreak of measles has reached a dangerous tipping point. What does ‘herd immunity’ mean, and why does that matter?

Welcome to New Zealand, 2019, where 850 cases of measles have been reported since January and experts are warning of mass contaminations at sports tournaments and public gatherings. 

I’m writing this from Auckland, where at least 731 cases have been confirmed, approximately one in three requiring hospitalisation. The Ministry of Health has issued warnings for anyone intending on travelling to Auckland, recommending visitors receive their vaccinations two weeks in advance.

The city is also under what is beginning to sound like a soft quarantine, with the ministry recommending anyone feeling sick should “reconsider travel arrangements, stay away from work, school and public places”.

That’s real ebola hours, fam. And it was wholly preventable had people simply vaccinated their kids. 

But some people can’t get vaccinations!

That’s right, some of our most vulnerable are unable to receive the MMR vaccination. Children undergoing chemotherapy, people with severe allergies, and those with compromised immune systems cannot be immunised. Babies under the age of 6 months, and often as late as 12 months, are also not immunised. Fortunately, they can still be protected by the rest of us through what is known as herd immunity.

What’s ‘herd immunity’, please?

When levels of vaccination in a community are high enough, contagious diseases like measles are unable to gain a foothold and those without immunity are protected. In an unvaccinated population, someone with measles will infect between 14 and 18 other people, but just two doses of the MMR vaccines protects 99 out of 100 vaccinated people. And provided 95 out of every 100 people are successfully vaccinated, there is a very high probability that those without immunity will be safe.

Great, so what’s the problem? 

Consider this very cool exchange from Susie Ferguson’s interview with the director of public health Dr Caroline McElnay on today’s Morning Report:

“So how close are we to losing herd immunity?”

*sharp intake of breath* 

• Twenty new measles cases per day as Auckland's outbreak worsens
• Anti-vaccination messages continue to spread amid New Zealand measles outbreak
• Anti-vaxxers target new parents, while others nurse their critically ill kids
• Auckland measles outbreak: Dr Lance O'Sullivan calls for 'no jab, no pay' concept

“……………….ahhh, herd immunity may be gone already.”

That’s right: in our supposedly first-world country, with free, first-world healthcare, people still aren’t vaccinating their kids, and it’s putting lives at risk. Measles is highly contagious and pretty bloody nasty when it strikes, leading in some cases to permanent brain damage and death, but apparently that doesn’t matter because some people just don’t want to vaccinate. 

Once more for the people in the back: the most vulnerable members of our community are being put at risk because parents refuse to vaccinate their kids. 

And it’s not just here. Last week, The Spinoff reported Californian health authorities had issued warnings after an infectious New Zealander spent five days in the state.  The Los Angeles Department of Public Health issued its own alert, listing the dates and times that the tourist was at locations including LAX airport, Universal Studios, TCL Chinese Theatres, Madame Tussauds and Santa Monica Beach. 

We’re exporting our diseases to the world like they’re milk powder.

Why aren’t people vaccinating? 

While you’d hope it’s mostly out of innocent ignorance, or the very real difficulties some families face in accessing a vaccine, that’s not always the case. You see, there are rabid, frothing, totally delusional communities of the intentionally misinformed campaigning tirelessly to bring back the horrific diseases of the past through fear-mongering and debunked junk science.

Anti-vaxxers, like diseases, thrive in grotty, dark crevasses like Facebook and the weirder parts of Reddit. They’re in parenting groups and on noticeboards. Sometimes they’re even hosting discussions in your local community hall. They spout baseless propaganda, preying on the fears of new parents and the uninformed. 

But there are people fighting back, some of them to the extreme. Shortly after storming the stage to protest a screening of the fraudulent and pseudoscientific hoax film Vaxxed, Dr Lance O’Sullivan told The Spinoff he believed vaccines should even be tied to benefits. It’s a bold suggestion, and one he was flayed for, but it would be a moot point if people would just get their shit together. 

So vaccinate your kids. Go today. Little Xander, Moon and sweet baby Blayne are just going to have to suck it up. Even if you think you might have had it, do it anyway – the vaccine is completely safe to receive more than once. But don’t just take my word for it, here’s our two-part series on vaccinationswritten by a real scientist from 2017. If a few more people had read it, we wouldn’t be in this predicament. 

We’ve got six months to turn this around before we lose our elimination status altogether.

If you’re aged 18 or over, you can still get free immunisation against measles, mumps and rubella. The vaccine is free for everyone born from 1 January 1969 onwards who hasn’t already had two recorded doses.