The federal Food and Drug Administration (FDA) issued a simple message ahead of its formal authorisation of the Pfizer-BioNTech COVID-19 vaccine on Monday (local time), as reluctant Americans continue to search for alternative treatments.
The US FDA is responsible for protecting public health by ensuring the safety, efficacy and security of drugs and other biological products. It regulates foods such as additives and supplements, prescription and non-prescription drugs, biologics, veterinary products and cosmetics, among others.
On Monday (local time), the regulator granted full approval to the Pfizer vaccine - the first to secure full FDA approval. Currently, New Zealand has opted to exclusively use the Pfizer formula in its vaccination campaign, as opposed to alternatives such as AstraZeneca or Johnson & Johnson.
In a tweet over the weekend, the FDA shared an official article explaining why people should not be using the drug ivermectin - a medicine used to deworm livestock - to treat or prevent COVID-19 as an alternative to the vaccine.
"You are not a horse," it said. "You are not a cow. Seriously, y'all. Stop it."
The accompanying article warns using ivermectin as a treatment or preventative measure - despite not being approved for that purpose by the FDA - can be dangerous, or even lethal.
"While there are approved uses for ivermectin in people and animals, it is not approved for the prevention or treatment of COVID-19," it reads.
"You should not take any medication to treat or prevent COVID-19 unless it has been prescribed to you by your healthcare provider and acquired from a legitimate source."
In Mississippi last week, the state's health department said at least one person was hospitalised after ingesting ivermectin.
Speaking to CNN on Sunday (local time), US surgeon general, Dr Vivek Murthy, reiterated that ivermectin should not be used to treat or prevent COVID-19.
"The best protection we have against COVID-19 is the vaccine, and if you get COVID-19, we actually do have treatments that work. Ivermectin is not one of them."
Misinformation has spread like wildfire on social media and through right-wing facets of US politics regarding purported treatments for COVID-19. In comments shared widely across social media, Dr Pierre Kory, a pulmonary and critical care specialist at Aurora St Luke's medical center in Milwaukee, called ivermectin a "wonder drug".
In July, evolutionary biologist Bret Weinstein told Fox News host Tucker Carlson that the vaccine debate "would be over by definition" if ivermectin "is what those of us who have looked at the evidence think it is".
In a Senate hearing last December, a number of doctors touted ivermectin alongside hydroxychloroquine, an anti-malaria drug once championed by former US President Donald Trump as a cure for COVID-19, despite no scientific backing.
Following that hearing, experts concluded there was no evidence that ivermectin was a supposed 'miracle' drug against COVID-19. Test results suggesting ivermectin could inhibit replication of the SARS-CoV-2 virus did not amount to official authorisation for use, they said.
"Claim: The antiparasitic drug ivermectin 'has a miraculous effectiveness that obliterates', the transmission of COVID-19 and will prevent people from getting sick," the Associated Press reported. "False. There's no evidence ivermectin has been proven a safe or effective treatment against COVID-19."
A number of states are currently struggling to boost their vaccination rates as the highly transmissible Delta variant runs rampant. The vast majority of deaths and hospitalisations in the US are among unvaccinated people.
On Saturday night at a 'Save America' rally in Alabama, the state with the lowest vaccination rate, Trump urged his supporters to get the shot, citing his own "good" experience with the vaccine. The former President was vaccinated at the White House in January after being hospitalised with the virus three months earlier. However, the public were not made privy to this information until March.
The crowd quickly turned on Trump and began booing and jeering, forcing him to quickly backpedal. He told his supporters he understood the need to exercise their "freedoms", but made it clear he was pro-vaccination - despite downplaying the pandemic for months in the final year of his presidency.
"If it doesn't work, you'll be the first to know," he joked.
According to an FDA fact-sheet, the agency has approved ivermectin to treat "certain internal and external parasites in various animal species".
"People should never take animal drugs [as] using these products in humans could cause serious harm," it says. "Any use of ivermectin for the prevention or treatment of COVID-19 should be avoided."
Side-effects associated with ingesting ivermectin include "skin rash, nausea, vomiting, diarrhoea, stomach pain, facial or limb swelling, neurologic adverse events (dizziness, seizures, confusion), sudden drop in blood pressure, severe skin rash potentially requiring hospitalisation, and liver injury (hepatitis).
"Laboratory test abnormalities include decrease in white cell count and elevated liver tests."
Ivermectin tablets have been approved for use in humans, the FDA said, for "the treatment of some parasitic worms". Formulations can be used by prescription only for the treatment of "skin conditions such as rosacea" and "external parasites such as head lice".