COVID-19 therapies, including antivirals and monoclonal antibodies, are making headlines. However, many COVID-19 treatments are currently in short supply, while others aren't effective against omicron.
"At this point, we have far more eligible patients than we have supply,” says infectious diseases expert Mark Rupp, MD. Nebraska Medicine is prioritizing available COVID-19 therapies to people at the highest risk. These treatments are not available at our emergency departments or clinics.
COVID-19 vaccines, on the other hand, are widely available and free. If you are not vaccinated and boosted against COVID-19, please do so as soon as possible. In a world where treatments may not be readily available to the extent we need, vaccination is the best way to protect yourself, your loved ones and your community.
How monoclonal antibodies work differently than vaccines
"Vaccines provide a baseline immunity that lasts for a minimum of four to six months," explains infectious diseases expert Diana Florescu, MD. "The antivirals are active for a few days, and most of the monoclonal antibodies protect you for a month or two. Monoclonal antibodies may help you, but only for a short time."
It works like the saying: "Give a man a fish, and you feed him for a day. Teach him how to catch fish, and you feed him for a lifetime."
Monoclonal antibodies and antivirals are short-term treatments because they don't teach your body anything. When the treatment fades away, so does your protection. Much like teaching someone how to fish, vaccines teach your body how to fight COVID-19.
It's a long-lasting lesson, too.
"Vaccines trigger your body to create its own antibodies," says Dr. Florescu. "So you can self-defend in case of infection. Monoclonal antibodies – antibodies created in a laboratory– provide passive immunity for a short period of time."
Treatment: monoclonal antibodies like sotrovimab
Monoclonal antibodies are man-made antibodies. These man-made antibodies can act as the "front line” fighters. They can begin tackling the virus right away, giving your body extra time to make its own antibodies.
"Some of the monoclonal antibodies that were developed over the last year are not effective against omicron,” says Dr. Rupp. "The virus has shifted, and those specific antibody treatments don't interact with the virus any longer.”
This includes bamlanivimab with estesevimab and casirivimab with imdevimab. Unfortunately, these monoclonal antibodies are not effective against the omicron COVID-19 variant.
"One monoclonal antibody, called sotrovimab, is effective against omicron,” says Dr. Rupp. "But we have very few doses – about four to five treatments of the infusion are available to us per day. We have dozens of folks who qualify for it. So we can only give it to people at highest risk.”
Treatments: oral antivirals like paxlovid and molnupiravir
The Food and Drug Administration (FDA) has authorized two antiviral treatments: paxlovid (Pfizer) and molnupiravir (Merck). These are oral, not intravenous, treatments – meaning they're pills, not infusions.
Antiviral drugs like paxlovid and molnupiravir attack the SARS-CoV-2 virus. They both target the virus' replication process:
- Paxlovid slows down viral replication. It inhibits (prevents) an enzyme that the virus needs to build copies of itself. If the virus can't replicate, it can't spread – and the immune system can fight it off more easily. In studies, paxlovid was nearly 90% effective in preventing progression of illness
- Molnupiravir, on the other hand, causes the virus to make mistakes every time it tries to replicate. Unfortunately, molnupiravir appears to be substantially less effective than paxlovid
The supply of both of these oral antivirals is limited. At this time, paxlovid is not being distributed to Nebraska Medicine.
Treatment: IV antiviral remdesivir (Veklury)
Remdesivir (also called Veklury) is an antiviral drug that must be given through a vein. Remdesivir has received FDA approval for certain patients.
Remdesivir blocks the machinery that the coronavirus (SARS-CoV-2) needs to make copies of itself. This stops the virus from replicating.
"Remdesivir is effective in preventing the progression of the disease,” says Dr. Rupp. "But it has to be given intravenously over three days. So logistically, it's difficult to get somebody into an infusion center for three days in a row to try to prevent the progression of the disease. We are reserving this treatment for the highest risk people.”
Prevention: monoclonal antibodies like evusheld
Another option to fight COVID-19 is a combination of monoclonal antibodies called evusheld. Evusheld is authorized by the FDA for pre-exposure prophylaxis. That means evusheld is used for prevention, not treatment, of COVID-19. Evusheld combines the monoclonal antibodies tixagevimab plus cilgavimab.
The National Institutes of Health COVID-19 Treatment Guidelines Panel recommends evusheld for people who are:
- Moderately to severely immunocompromised and may have an inadequate immune response to COVID-19 vaccination, or
- Unable to be fully vaccinated with any available COVID-19 vaccines due to a documented history of severe reactions to a COVID-19 vaccine or any of its components
"We have between 9,000 to 10,000 patients who would qualify for evusheld,” says Dr. Rupp. "Unfortunately, we only receive doses for about 50 to 100 people per week for this treatment to prevent illness. We've had to prioritize doses for those at greatest risk.”
All monoclonal antibody therapies are currently under emergency use authorization (EUA) through the FDA. They are not yet fully FDA-approved and supply and shipping is under direction of federal and state government.