The first doses of a COVID-19 vaccine have been given, and hope for the eventual end of the pandemic is in sight. There’s a long road ahead before everyone is vaccinated—around the world, not just in the United States—but the good news for those who get COVID-19 between now and then is that we know more about treating this disease now than we did in the early months of the pandemic.
Some of the most promising COVID-19 treatments have relied on giving the patient’s own immune system a boost using antibodies from other people.
Once someone is exposed to a pathogen, their immune systems tries to develop antibodies against it, but the process of developing one’s own antibodies can take some time. Adding antibodies from another source to the bloodstream can buy that time. Doctors have been using plasma, the liquid part of blood, that contains antibody proteins against COVID-19 for this purpose. This so-called convalescent plasma is drawn from people who have already had the disease (hence the name).
Convalescent plasma contains more than just COVID-19 antibodies, which means it’s not the strongest treatment. The jury is still out on whether or not convalescent plasma offers a substantial benefit.
In the meantime, researchers have been working to supercharge the immune system using lab-made COVID-19 antibodies, called monoclonal antibodies, that can shore up a patient’s immune system ahead of its own antibodies. Two companies, Eli Lilly and Regeneron, have been granted an Emergency Use Authorization (EUA) by the Food and Drug Administration for their monoclonal antibodies.
But monoclonal antibodies aren’t a cure. Their use is only recommended for people who are newly infected with SARS-CoV-2 to help keep the disease from taking root. In a Nature Biotechnology commentary from October, a panel of experts note these treatments are hard to develop and are generally used mostly for diseases that we don’t have vaccines for, like HIV. In the case of COVID-19, they note, monoclonal antibodies may prove most useful to help people who don’t respond to a vaccine—for example, older adults with weakened immune systems—since they may still be susceptible after the rest of the population is immunized.
Antivirals work by targeting virus’ ability to create energy and replicate themselves. In early December, the World Health Organization released results from a large-scale trial of three antivirals: remdesivir, hydroxychloroquine, and lopinavir. Its results led the international organization to conclude that the drugs had “little or no effect on hospitalized patients with COVID-19.”
Remdesivir, the most widely used drug of this class in treating COVID-19, works by blocking an enzyme that SARS-CoV-2 uses to replicate itself. Remdesivir was initially designed to combat Ebola, and although it didn’t prove effective for that disease, the Ebola studies demonstrated that the drug was at least not harmful to humans. That can be a tricky thing about antivirals: they often have serious side effects, since the mechanism of action they’re blocking isn’t always unique to a virus. It might be something your cells need to do as well.
Take, for example, hydroxychloroquine and chloroquine, potent antimalarials that have been shown to be ineffective against COVID-19. These drugs work by impairing a part of the cell called the lysosome, which basically breaks down and gets rid of cellular garbage. In the single-celled parasite that causes malaria, messing up its lysosome kills it. But these drugs also screw with the lysosomes inside your cells too, which accounts for the serious side-effects they have. They’re only recommended for use in cases where the benefits of the treatment outweigh the harmful side-effects.
Another antiviral, favipiravir, is still being investigated for use against COVID-19. It’s been approved for use by some countries, including India. But we’re still learning more about its effectiveness and the FDA has not yet approved it.
Steroids like dexamethasone have been used to treat the worst effects of COVID-19 by reducing the body’s own immune response. They’re effective in reducing the potentially life-threatening inflammation that results from severe infection and can cause Acute Respiratory Distress Syndrome (ARDS), which is the main cause of COVID-19 fatalities.
But just like antivirals, sometimes the side effects from steroids can actually make things worse. Since steroids suppress the immune system, they can also make it harder for your body to fight off a COVID-19 infection. The trick is in knowing when they can be more helpful than harmful, and which dose is best. Here again, research is ongoing, but trials earlier in the year demonstrated that steroids definitely can help in treating the most severely affected COVID-19 patients.
A whole host of other treatments have been tried for COVID-19, but none of them have been shown to be effective. Even as our methods have advanced, the best route is still to try and avoid getting sick if at all possible. Wear a mask, maintain social distance, wash your hands, and stay at home as much as possible. A vaccine is coming—we just need to keep each other safe until then.