The US Food and Drug Administration (FDA) on Thursday authorized Merck’s Covid pill for high risk adults amid a winter surge of cases driven by the highly infectious Omicron variant.
The decision to grant an emergency use authorization came a day after the agency gave a green light to a similar but more effective pill developed by Pfizer.
“Today’s authorization provides an additional treatment option against the Covid-19 virus in the form of a pill that can be taken orally,” said FDA scientist Patrizia Cavazzoni.
The pill developed by Merck, which is known as MSD outside the US and Canada, is taken within five days of symptom onset and was shown in a trial of 1,400 participants to reduce Covid hospitalizations and deaths by 30 percent among at-risk people.
Pfizer’s pill reduced the same outcomes by almost 90 percent.
While vaccines and boosters remain the foremost tools in the fight against the virus, experts have welcomed the addition of new oral treatments, which should eventually be easy to access at pharmacies following a prescription.
Until now, the main treatments have been synthetic antibodies or Gilead’s antiviral remdesivir, which are administered by infusion.
Because neither Pfizer nor Merck’s treatments target the ever-mutating spike protein that dots the surface of the virus, they should be more able to withstand new variants, such as Omicron.
Both companies have said early lab testing has borne out this hypothesis.
While both treatments were found to be generally safe in clinical trials, more potential concerns have been raised about Merck’s pill, called molnupiravir.
Safety concerns
The FDA has not authorized Merck’s pill for people under 18 because it may affect bone and cartilage growth.
It is not recommended for use in pregnant women because of the potential fetal harm which was identified in animal testing, but doctors can still decide if the benefits outweigh the risks in individual cases.
Independent experts convened by the FDA narrowly voted in favor of authorizing molnupiravir in early December. Several who voted “no” highlighted the potential risks.
Preliminary data about its efficacy was more encouraging, suggesting a 50 percent reduction in severe Covid, but this was later downgraded to 30 percent after the final analysis included more cases.
The FDA did not convene a panel of experts to discuss Pfizer’s pill, instead opting to authorize it without seeking their advice.
Eight capsules of molnupiravir are taken orally for five days, for a total of 40 capsules.
The US has paid for 3.1 million courses of Merck’s treatment, for about $2.2 billion, and 10 million courses of Pfizer’s for $5.3 billion.
Molnupiravir works by incorporating itself into the genome of the virus, causing mutations that prevent viral replication.
The drug has previously been authorized in Britain and Denmark.

News
Repurposed drugs could calm the immune system’s response to nanomedicine
An international study led by researchers at the University of Colorado Anschutz Medical Campus has identified a promising strategy to enhance the safety of nanomedicines, advanced therapies often used in cancer and vaccine treatments, [...]
Nano-Enhanced Hydrogel Strategies for Cartilage Repair
A recent article in Engineering describes the development of a protein-based nanocomposite hydrogel designed to deliver two therapeutic agents—dexamethasone (Dex) and kartogenin (KGN)—to support cartilage repair. The hydrogel is engineered to modulate immune responses and promote [...]
New Cancer Drug Blocks Tumors Without Debilitating Side Effects
A new drug targets RAS-PI3Kα pathways without harmful side effects. It was developed using high-performance computing and AI. A new cancer drug candidate, developed through a collaboration between Lawrence Livermore National Laboratory (LLNL), BridgeBio Oncology [...]
Scientists Are Pretty Close to Replicating the First Thing That Ever Lived
For 400 million years, a leading hypothesis claims, Earth was an “RNA World,” meaning that life must’ve first replicated from RNA before the arrival of proteins and DNA. Unfortunately, scientists have failed to find [...]
Why ‘Peniaphobia’ Is Exploding Among Young People (And Why We Should Be Concerned)
An insidious illness is taking hold among a growing proportion of young people. Little known to the general public, peniaphobia—the fear of becoming poor—is gaining ground among teens and young adults. Discover the causes [...]
Team finds flawed data in recent study relevant to coronavirus antiviral development
The COVID pandemic illustrated how urgently we need antiviral medications capable of treating coronavirus infections. To aid this effort, researchers quickly homed in on part of SARS-CoV-2's molecular structure known as the NiRAN domain—an [...]
Drug-Coated Neural Implants Reduce Immune Rejection
Summary: A new study shows that coating neural prosthetic implants with the anti-inflammatory drug dexamethasone helps reduce the body’s immune response and scar tissue formation. This strategy enhances the long-term performance and stability of electrodes [...]
Scientists discover cancer-fighting bacteria that ‘soak up’ forever chemicals in the body
A family of healthy bacteria may help 'soak up' toxic forever chemicals in the body, warding off their cancerous effects. Forever chemicals, also known as PFAS (per- and polyfluoroalkyl substances), are toxic chemicals that [...]
Johns Hopkins Researchers Uncover a New Way To Kill Cancer Cells
A new study reveals that blocking ribosomal RNA production rewires cancer cell behavior and could help treat genetically unstable tumors. Researchers at the Johns Hopkins Kimmel Cancer Center and the Department of Radiation Oncology and Molecular [...]
AI matches doctors in mapping lung tumors for radiation therapy
In radiation therapy, precision can save lives. Oncologists must carefully map the size and location of a tumor before delivering high-dose radiation to destroy cancer cells while sparing healthy tissue. But this process, called [...]
Scientists Finally “See” Key Protein That Controls Inflammation
Researchers used advanced microscopy to uncover important protein structures. For the first time, two important protein structures in the human body are being visualized, thanks in part to cutting-edge technology at the University of [...]
AI tool detects 9 types of dementia from a single brain scan
Mayo Clinic researchers have developed a new artificial intelligence (AI) tool that helps clinicians identify brain activity patterns linked to nine types of dementia, including Alzheimer's disease, using a single, widely available scan—a transformative [...]
Is plastic packaging putting more than just food on your plate?
New research reveals that common food packaging and utensils can shed microscopic plastics into our food, prompting urgent calls for stricter testing and updated regulations to protect public health. Beyond microplastics: The analysis intentionally [...]
Aging Spreads Through the Bloodstream
Summary: New research reveals that aging isn’t just a local cellular process—it can spread throughout the body via the bloodstream. A redox-sensitive protein called ReHMGB1, secreted by senescent cells, was found to trigger aging features [...]
AI and nanomedicine find rare biomarkers for prostrate cancer and atherosclerosis
Imagine a stadium packed with 75,000 fans, all wearing green and white jerseys—except one person in a solid green shirt. Finding that person would be tough. That's how hard it is for scientists to [...]
Are Pesticides Breeding the Next Pandemic? Experts Warn of Fungal Superbugs
Fungicides used in agriculture have been linked to an increase in resistance to antifungal drugs in both humans and animals. Fungal infections are on the rise, and two UC Davis infectious disease experts, Dr. George Thompson [...]