Infectious diseases expert Diana Florescu, MD, has been involved in several COVID-19 clinical trials: the vaccine candidate from Novavax, the monoclonal antibody cocktail from Regeneron and the antiviral pill molnupiravir.
"It's extremely exciting to do these clinical trials, in the hope that this will impact the pandemic," says Dr. Florescu. "It's almost like having a baby – you get to see it go through all the phases. And it's incredible to see something go from being tested in trials to being a successful treatment."
"We're also very grateful to all the participants."
Here Dr. Florescu explains why SARS-CoV-2 vaccines and COVID-19 treatments are not mutually exclusive.
Then she gives updates on three COVID-19 treatments: antiviral molnupiravir, antiviral remdesivir and an antibody cocktail created by AstraZeneca.
How treatments work differently than vaccines
"Antivirals, like remdesivir or molnupiravir, and monoclonal antibodies should not be used to replace vaccines," says Dr. Florescu.
"Vaccines provide a baseline immunity that lasts for several months," explains Dr. Florescu. "The antivirals are active for a few days, and 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," explains 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."
The bottom line: The vaccine is the best way to protect yourself against COVID-19. Get vaccinated.
Merck's antiviral molnupiravir
Dr. Florescu led a phase 3 clinical trial at University of Nebraska Medical Center (UNMC) to evaluate if molnupiravir was safe and effective to reduce hospitalization and death in non-hospitalized COVID-19 patients. The study included people with mild to moderate COVID-19. Molnupiravir is taken orally, not intravenously – meaning it's a pill, not an infusion.
Results. According to a company press release, molnupiravir reduced the risk of hospitalization or death by approximately 50% compared to placebo. Merck says that adverse events found in the treatment and placebo groups were similar. The clinical trial results are still under review by experts in the field, after which the results are expected to be published..
How it works. Antiviral drugs like molnupiravir attack the SARS-CoV-2 virus. Molnupiravir causes the virus to make mistakes every time it tries to copy itself. If the virus can't replicate, it can't spread – and the immune system can easily fight it off.
"The earlier you start treatment, the better," says Dr. Florescu. That's why the clinical trial tested giving molnupiravir early in participants' illness – just five days or fewer of COVID-19 symptoms.
What's next? Merck plans to seek emergency use authorization from the FDA soon. If authorized, the antiviral pills will be the first COVID-19 treatment available in pill form.
Gilead Sciences' antiviral remdesivir
Remdesivir (also called Veklury) is the only COVID-19 antiviral drug available, so far. It's reserved for hospitalized COVID-19 patients and must be given through a vein.
Results. "For COVID-19 inpatients, remdesivir has been shown to reduce hospital stays and reduce the number of deaths," says Dr. Florescu.
Researchers are also trying to see if timing matters. Might remdesivir be more effective if given earlier in the infection? It's too soon to say, but this is an ongoing research question. The drug may be more beneficial if taken before COVID-19 gets serious.
How it works. Remdesivir works slightly differently than molnupiravir. Both drugs are antivirals that stop the replication of SARS-CoV-2. Remdesivir blocks the machinery that the virus needs to make copies of itself.
What's next? Gilead Sciences is developing a pill version of remdesivir. A pill version will have to go through all three phases in a new clinical trial to test its safety and effectiveness.
AstraZeneca's antibody cocktail AZD7442
AstraZeneca has created a potential COVID-19 treatment, called AZD7442. This is an intramuscular injection of an antibody cocktail that combines two antibodies.
Results. According to a company press release, the drug reduces the risk of severe COVID-19 or death by 50% in non-hospitalized patients. The drug appeared to be more effective for patients who started therapy within five days of their first symptoms. The clinical trial results are still under review by experts in the field, after which results are expected to be published.
AstraZeneca also says that the drug can prevent symptomatic COVID-19, if given as a preventive treatment.
How it works. This is an intramuscular injection of man-made antibodies. Many other antibody cocktails require an infusion at a treatment center.
What's next? AstraZeneca has sent these results to the FDA, which will review the data. The company states that its results will also be published in a peer-reviewed medical journal.
Currently authorized antibody treatment infusions
Sotrovimab and casirivimab with imdevimab, are COVID-19 neutralizing antibody treatment intravenous infusions with emergency use authorization for mild to moderate disease.
Nebraska Medicine offers these two antibody treatment infusions to certain eligible individuals. These treatments are not available at our emergency departments or clinics. Rather, doctors can prescribe this treatment based on a variety of risk factors.