An expert is urging Kiwis to be more sceptical of trusting health claims they see in memes on social media after a man overdosed on livestock dewormer.
A Sydney man ended up in hospital earlier this week after self-administering ivermectin in a futile attempt to treat his COVID-19, Australian media reported.
Ivermectin is an anti-parasitic listed as an essential medicine by the World Health Organization, but there's no evidence it works against COVID-19, which is a virus - not a parasite like scabies or roundworm.
It's been promoted as both a prevention and a cure by anti-vaccination activists, supporters of alternative medicine and - in the US at least - right-wing activists and media. People who can't get it from their doctor are turning to ivermectin paste sold by vets for use in animals like horses.
The Sydney man ordered ivermectin online, and took so much he was hospitalised suffering vomiting and diarrhoea. The hospital's toxicologist told local media he'd recover, but "it didn't help their COVID either".
Nikki Turner, a professor of primary care at the University of Auckland and director of the Immunisation Advisory Centre says the Australian man had fallen victim to misinformation, which has been rife during the pandemic.
"There's mixed data on whether it might have a small amount of effectiveness or not as a medication. It's absolutely not clear," she said in an online discussion with journalists this week.
"The data to date and the most recent meta-analysis suggests it's not. That poor chap unfortunately has just been caught by social media and some of the memes running around."
One of the most-cited studies behind the claims ivermectin works on COVID-19 was allegedly carried out last year in South America - allegedly, because there is growing evidence the research never actually took place, or was heavily falsified. Another major study backing ivermectin was withdrawn after irregularities in its data were found - such as some of the alleged participants having died months before the trial even began.
Dr Turner said the enthusiasm for ivermectin, despite no evidence it works, could be traced back to former US President Donald Trump's promotion of the equally ineffective hydroxychloroquine.
"[It's] a really unfortunate effect of people using social media and a little bit of mixed-up science that hasn't been put together."
The US Federal Drug Administration recently warned people not to self-administer ivermectin intended for animals.
"You are not a horse. You are not a cow," it tweeted. "Seriously y'all. Stop it."
Investigations into ivermectin's efficacy - and that of numerous other drugs - are ongoing. In the meantime, there is a proven way to significantly reduce your chance of contracting COVID-19 - getting vaccinated.
There has reportedly been growing concern on social media about the efficacy of vaccines, with vaccinated people accounting for growing percentages of those diagnosed with the disease.
Dr Turner said that's to be expected - and isn't proof they don't work.
"If you had 100 people and you gave them all COVID, 100 people would get sick," she said (COVID-19 is the disease, not the virus - not everyone exposed to the virus develops COVID-19).
"If out of those 100, 90 of them were vaccinated then the 10 unvaccinated would get sick and around about five of the vaccinated would get sick. So then you have an absolute number of 15 sick as opposed to 100, but within those 15 sick one-third of them are vaccinated.
" Somebody who doesn't understand the simple arithmetic would go 'the vaccine's not working', but if you [compare] the absolute numbers in the first scenario it's 100, whereas in the vaccinated scenario it's 15, so the absolute numbers are way less."
Those worried about long-term side effects of the Pfizer vaccine, which uses a new kind of technology based on mRNA to prompt an immune response, shouldn't be, Dr Turner said. Billions of doses have been given, and New Zealand was late to start, meaning we had the advantage of seeing how well it worked overseas, as well as its safety record.
"This is a vaccine that's actually got scrutinised background data on way bigger doses than I've ever seen on any other vaccine I've worked with historically," she said. "I think of the medications, cosmetics, all of the other stuff I consume - none of these have anything like the safety scrutiny."