How Do COVID-19 Antiviral Drugs Work?

Alexis Bryan
Alexis Bryan23 Aug 2022

COVID-19 antiviral drugs work by preventing the coronavirus from replicating inside our cells. Currently, Remdesivir and Paxlovoid (Nirmatrelvir) are the only Food and Drug Administration-approved antiviral drugs for the treatment of COVID-19.

For now, frequent COVID-19 testing is the best way to reduce the spread of infection. If you are looking for a COVID test appointment, or any other lab tests, join Mira today. A membership with Mira provides you access to low-cost lab testing, affordable urgent care visits, and excellent customer service to get you the care you need for only $25 per month.

How COVID-19 Antiviral Drugs Work

COVID-19 antiviral drugs work by slowing or halting the virus’s replication process. This stops the spread of the virus throughout your body, reduces disease severity, and allows your body to focus on recovering. Although antiviral drugs may not completely cure the infection, less virus in your body means you will have a less severe case and reduced risk of serious complications from COVID-19.

Antiviral drugs are an effective treatment for COVID-19 but do not replace the role of vaccines. There are two types of antiviral drugs: antiviral pills and antiviral therapy. Antiviral pills are taken by mouth and antiviral therapy is administered via an intravenous (IV) infusion by a healthcare provider. 

Each antiviral drug works a little bit differently in the body and poses different risks to patients. The three general ways antiviral drugs work are:

  • Block receptors so viruses can’t bind to and enter healthy cells
  • Boost the immune system, helping it fight off a viral infection
  • Lower the viral load (amount of active virus) in the body

For this reason, it is necessary to understand the role of antiviral medications in treating

mild, moderate, severe, and critical illness in order to optimize treatment for people with COVID-19.

How to Access COVID-19 Antiviral Drugs

There are two antiviral drugs currently approved for COVID-19 treatment: Remdesivir and Paxlovoid. Remdesivir is administered in the hospital, while Paxlovoid is intended for at home use.


To use Remdesivir for COVID-19 treatment, you must have a prescription. It is only administered to patients in a hospital setting. There has been a lot of misinformation surrounding COVID-19 treatment, and it is important to discuss with a healthcare professional before taking an antiviral drug. Many drugs have serious side effects.


Pfizer recently received approval for Paxlovid (ritonavir). Paxlovoid has proven to reduce the risk of hospitalization and death from COVID-19 by up to 90%, including against the omicron variant. Patients will need a positive COVID-19 test to get a prescription for the antiviral drug.

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Approved Antiviral COVID-19 Drugs

New drugs must go through extensive research before getting FDA approval. The process starts with pre-clinical trials, then safety testing in animals, safety testing in humans, and finally testing for effectiveness in humans.

There have been multiple antiviral drugs studied for the treatment of COVID-19, but most have proven ineffective. Currently, there is only two antiviral drugs to treat COVID-19.

Drug NameWho Can Take
  • Hospitalized adult and pediatric patients (aged ≥12 years and weighing ≥40 kg)


An EUA* is available for:

  • Hospitalized pediatric patients weighing 3.5 kg to <40 kg
  • Or aged <12 years and weighing ≥3.5 kg
  • Patients aged ≥12 years and weighing ≥40 kg with a positive COVID-19 test

*EUA = emergency use authorization; FDA may authorize unapproved medical products or unapproved uses of approved medical products to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases.

COVID-19 Treatment Guidelines Panel Recommendations

The COVID-19 Treatment Guidelines Panel (the Panel) also provides recommendations against the use of drugs that are found to be not effective in clinical trials or have insufficient evidence in support of their use. The following drugs are not recommended for the use in the treatment of COVID-19:

  • Ivermectin (insufficient evidence)
  • Nitazoxanide
  • Hydroxychloroquine or Chloroquine and/or Azithromycin
  • Lopinavir/Ritonavir and Other HIV Protease Inhibitors

COVID-19 Antiviral Pills

As seen in recent news, Merck is also developing an antiviral pill to treat COVID-19, and mass production of Paxlovoid will soon make antiviral treatment more accessible. The approval for wide use of antiviral pills for COVID-19 is a promising step towards ending the Covid-19 pandemic.

COVID-19 Antiviral Drugs Frequently Asked Questions (FAQs)

COVID-19 antiviral drugs are currently being studied by scientists to see if they can effectively cure COVID-19 infection. There will likely be more information available in the near future, but we answer a few preliminary questions below.

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Can antivirals cure viral infections?

Antiviral drugs can ease symptoms, shorten the length of infection, and cure viral infections unless the infection is chronic. Viral infections like HIV, hepatitis, and herpes are chronic, and therefore antivirals can not cure them. However, antiviral medicines can make the virus latent (inactive) which reduces, or completely eliminates, symptoms. 

Who will be able to access the new COVID-19 antiviral drugs?

Due to the novelty of COVID-19 antiviral drugs for the treatment of COVID-19, there will be limitations in place on who can access them when they become available for people who are not hospitalized. There are safety concerns associated with all drugs, but especially so with new drugs on the market.

The first “tier” of patients to prioritize for treatment are immunocompromised individuals and those who are unvaccinated and older than 75 years or 65 years with additional risk factors. People who are immunocompromised will need to be monitored closely as COVID-19 antivirals become more accessible. Since COVID-19 infection typically lasts longer in these populations, there is more opportunity for resistance to develop and adverse reactions.

Pregnant patients and children are often excluded from clinical trials at first, so they will also likely not be recommended to take COVID-19 antiviral drugs until more research is conducted. 

What is an Emergency Use Authorization?

The Emergency Use Authorization (EUA) authority allows FDA to respond to public health threats, including infectious diseases, by facilitating the availability and use of medical products to diagnose, treat, or prevent disease. When there are no adequate, approved, and available alternatives, the EUA expedites the time for people to access essential medical products.

In terms of COVID-19, there have been EUAs administered for vaccines, drugs, and the following:

  • Blood Purification Devices
  • Continuous Renal Replacement Therapy and Hemodialysis Devices
  • In Vitro Diagnostics
  • Decontamination Systems for Personal Protective Equipment
  • Infusion Pumps
  • Personal Protective Equipment
  • Remote or Wearable Patient Monitoring Devices
  • Respiratory Assist Devices
  • Ventilators and Ventilator Accessories
  • And more

Bottom Line

The COVID-19 pandemic has prompted great medical advancement and lightspeed innovation in the healthcare sector. Antiviral drugs are one of the many treatments being developed for the treatment of COVID-19 and will soon enter the market for at-home treatment. 

If you are experiencing flu-like symptoms and want to get a COVID-test, Mira can help you find an appointment near you. In addition, a membership with Mira can help you access affordable urgent care visits, lab testing, and up to 80% off prescription drug prices.

Alexis Bryan

Alexis Bryan MPH, is a recent graduate of Columbia’s Mailman School of Public Health. She is passionate about increasing access to care to improve health outcomes. Outside of work, she loves to travel, read, and pay too much attention to her plants.