On Sunday, it was announced that the world's longest-reigning current monarch, Queen Elizabeth II, had tested positive for COVID-19.
The news of the 95-year-old sovereign's diagnosis sparked media attention worldwide, including in Australia, where she has been the head of state since her coronation in 1953.
But the story also sparked a conspiracy theory, after an editing mistake by an Australian news programme appeared to suggest the Queen was being given ivermectin, an antiparasitic drug that has become popular among anti-vaxxers and COVID-19 sceptics.
The Nine Network's A Current Affair programme quickly apologised for the mistake and re-edited the segment on the Queen's COVID-19 diagnosis, saying "we do not suggest the Queen is using ivermectin".
Buckingham Palace has not commented on the specific details of the Queen's treatment, but the drug is not approved for use as a COVID-19 treatment in the United Kingdom, where she lives.
She received her first COVID-19 vaccine in January last year, and is believed to have had her second and third jabs since then.
The error occurred on Monday evening, when A Current Affair broadcast a report on the Queen's positive COVID-19 test.
The segment featured an interview with Melbourne-based doctor Mukesh Haikerwal, who explained potential treatment options for elderly COVID-19 patients.
As Haikerwal spoke, the programme showed stock images of drugs, first two vials of the monoclonal antibody Sotrovimab - which has been authorised as a COVID-19 treatment - and then a packet of ivermectin tablets, shown under the brand name Stromectol.
"Ivermectin never even came into the conversation," Haikerwal told Guardian Australia. "I said there are medications available for people who are vulnerable… I didn’t even name them, but it was obviously Sotrovimab.
"It certainly wouldn’t be ivermectin. I wouldn’t recommend it," he added.
On Tuesday, the programme apologised for the mistake, blaming "human error" for the "accidental" inclusion of a shot of ivermectin.
"As a programme, we've done numerous stories highlighting the concerns around taking ivermectin as a treatment for COVID-19," it said in a statement.
But while the mistake was taken down from Nine Network's official channels, clips featuring the packet of ivermectin spread rapidly on social media.
One clip from the report posted to Twitter by a right-wing account with a history of misinformation about the pandemic had been watched 1.7 million times at the time of writing.
A number of Australia's COVID-19-sceptic politicians also shared the footage, with multiple elected representatives of the conservative Liberal-National governing coalition posting it on social media.
"What does Channel 9 know that we don’t," one said.
"We do not suggest the Queen is using ivermectin," the network said on Tuesday.
What is ivermectin?
Ivermectin is a drug typically used to treat parasites in animals like cows, horses and dogs.
It is not authorised for use against COVID-19 in the European Union and is not effective against the virus in its current form, the European Medicines Agency (EMA) has said.
While the drug is used in humans, it is only approved by medical regulators as a treatment for ailments including onchocerciasis (river blindness), intestinal strongyloidiasis (an illness caused by roundworms), head lice and rosacea.
The EMA and Centres for Disease Control and Prevention (CDC) in the United States have both warned against using ivermectin to treat COVID-19.
In September last year, Australia's medical regulator updated its guidance on ivermectin to specifically prohibit the drug's use as a COVID-19 treatment, saying "there are a number of significant public health risks associated with taking ivermectin in an attempt to prevent COVID-19 infection rather than getting vaccinated".
Ivermectin is not an approved COVID-19 treatment in Australia, the regulator stated.