One of the common symptoms of COVID-19 is fever, and a drug called ibuprofen, found in the leading brands Advil and Motrin, is one of the most-trusted fever reducers available without a prescription.
Early in the novel coronavirus epidemic, people were told to stock up on over-the-counter medications including ibuprofen to help reduce mild fevers if asked to ride out a viral illness at home.
But recently, French Minister Olivier Veran, a physician, tweeted that anti-inflammatory medications like ibuprofen "could be a factor in aggravating the infection," encouraging patients to take acetaminophen, which is found in Tylenol, for a fever instead.
His comments sparked a wave of controversy about the safety of ibuprofen for fevers associated with COVID-19, with experts weighing in on both sides. Although its safety is still being studied, for now, the world's leading scientists at the World Health Organization have said people shouldn't shy away from using ibuprofen to help mild fevers.
Drug companies that make over-the-counter painkillers told ABC News that they're monitoring the rapidly evolving situation and that patients should consult with healthcare providers about any concerns.
A spokesperson for Johnson & Johnson, which makes both Motrin and Tylenol, said the company "is taking all possible measures to maximize product availability across our OTC medicine portfolio to ensure broad access in all markets around the world.”
A spokesperson for GlaxoSmithKline, which produces Advil, said: "This is an emerging and rapidly evolving situation, and because consumer safety is our number one priority, we are closely monitoring statements from the public health authorities and medical experts."
Concerns about ibuprofen and other fever reducers may have been kick-started by fake WhatsApp messages circulating online. While normally such claims would be ignored by medical professionals, the online conspiracy fell on the heels of a hypothesis published in a prestigious scientific journal, the Lancet, which said there may be a scientific rationale for COVID-19 patients to avoid ibuprofen.
MORE: Government response updates: Trump calls himself a 'wartime president,' promises 'total victory'That theory draws on molecular biology. Because the virus that causes COVID-19 is known to bind to a specific protein in the body called ACE2, any medication that can increase ACE2, like ibuprofen, could theoretically increase the risk for a more severe COVID-19 infection.
In addition to ibuprofen, other medications like ACE inhibitors and angiotensin receptor blockers, a widely used group of blood pressure-lowering medications, have been thought to potentially increase ACE2.
But these are just theories.
Because of the thin evidence, numerous professional societies have come out against the French official's claim. One of these groups was the Infectious Diseases Society of Ireland, stating that the circulating message was "a fake message" and that patients can still take ibuprofen and other nonsteroidal anti-inflammatories for COVID-19 infections.
Ireland's Health Service Executive also said, "Regular medication, including anti-inflammatory medication, may be continued by people with COVID-19, unless advised otherwise by their healthcare professional." The Spanish Ministry of Health also said that there is no evidence that ibuprofen or other NSAIDs make the novel coronavirus worse.
MORE: How the US military is being utilized in responding to coronavirusInitially, a representative for the World Health Organization reportedly said at a press conference on Tuesday that patients should use paracetamol or acetaminophen in favor of ibuprofen.
Since then, the WHO has effectively retracted that warning statement. A representative from the organization said WHO "is gathering further evidence on this issue before making a formal recommendation, but after a rapid review of the literature, is not aware of published clinical or population-based data on this topic."
However, the WHO clearly announced on Wednesday evening that it does "not recommend against the use of ibuprofen" because it is "not aware of reports of any negative effects, beyond the usual ones that limit its use in certain populations."
Meanwhile, prior scientific studies seem to suggest other anti-inflammatory medications might actually be beneficial. One study found that indomethacin, a drug similar to ibuprofen, may help fight SARS-CoV, a closely related virus that caused SARS. However, this study was not performed in humans.
With these conflicting reports, the public is left wondering whether medicines perhaps stockpiled stockpiled at home are the correct ones.
Physicians, too, are now contemplating how to best counsel their patients. Many, like Dr. Daniel DeSimone, an infectious disease physician at Mayo Clinic, acknowledged that the data is too limited to be certain.
MORE: Small business owners tapping into personal savings, 401(k)s and more amid coronavirus crisis"From my review, there is no solid evidence that ibuprofen can make coronavirus symptoms and/or outcomes worse. At this time, there is no reason to avoid ibuprofen for pain or fever in COVID-19 patients," he said. "While Tylenol is typically used as a first-line agent, ibuprofen and other NSAIDS can be considered assuming they don't have an underlying contraindication such as renal disease. We will keep monitoring as more data comes in, so we will get a better grasp on the situation and deliver the best care possible to all our patients."
Dr. Simone Wildes, an infectious disease specialist at South Shore Hospital, echoed the need for additional studies.
"The use of ibuprofen in COVID-19 infection is a common question being posed by clinicians and patients," Wildes told ABC News. "More research is needed to study the effects of ibuprofen in patients with COVID-19 infection. We simply don't know the answer at this time. We need more data."
Other physicians, like Dr. Lalita Abhyankar, a family medicine physician at the Institute for Family Health, are taking a more cautious approach.
"I've been advising people that given the international concerns, it's best to treat any fever with acetaminophen instead of ibuprofen at this time. Taking it for headache or other joint pain might still be OK, we're just not sure yet because of the minimal data."
Irrespective of its questionable impact on COVID-19, doctors have said patients with kidney disease and stomach ulcers should try to minimize their use of ibuprofen. It's also not recommended in infants young than 6 months. Patients who are concerned should consult with their physicians on whether ibuprofen use is right for them in the context of their non-COVID19-related medical issues.
DeSimone encouraged the public to brace for ongoing change as experts learn more about this new virus.
"We have to realize that new information is coming in every day, and some things that we do today may be different tomorrow," DeSimone said.
Chloë E. Nunneley, M.D., a pediatric resident physician at Boston Children's Hospital and Boston Medical Center, and Vinayak Kumar, M.D., MBA, an internal medicine resident at Mayo Clinic, are contributors to the ABC News Medical Unit. Sony Salzman is the unit's coordinating producer.