March 2021

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Understanding COVID-19

How To Protect Yourself During the Pandemic

COVID-19 has claimed millions of lives around the world. But we learn more about this disease every day. Scientists are developing tools that promise to slow and eventu­ally help us overcome the pandemic.

COVID-19 is caused by a new coronavirus called SARS-CoV-2. There are many types of coronaviruses. Some cause the common cold. Others have led to fatal disease outbreaks. These include severe acute respiratory syndrome (SARS) in 2003, Middle East respiratory syndrome (MERS) in 2012, and now COVID-19.

Coronaviruses are named for the crown-like spikes on their surface. (Corona means crown.) The viruses use the spikes to help get inside your body’s cells. Once inside, they replicate, or make copies of themselves.

Scientists have learned how to turn these spikes against the virus through vaccines and treatments. They’ve also learned what you can do to protect yourself from the virus.

Protecting Yourself

You’re most likely to get COVID-19 through close contact with someone who’s infected. Coughing, sneezing, talking, and breathing produce small droplets of liquid. These are called respiratory droplets. They travel through the air and can be inhaled by someone else.

“COVID-19 is spread mainly through exposure to respiratory droplets that tend to drop within six feet,” says Dr. Anthony Fauci, director of NIH’s National Institute of Allergy and Infectious Diseases. That’s why it’s important to stay at least six feet (about two arm lengths) away from people who don’t live with you.

“Surfaces can be contaminated. But it is likely that this is a less common cause of infection rather than person-to-person directly,” Fauci says.

You can protect yourself and others by wearing a mask. Choose one that has at least two layers of fabric. Make sure that the mask covers your mouth and nose and doesn’t leak air around the edges.

“There’s very little transmission in places where masks are worn,” says Dr. Ben Cowling at the University of Hong Kong who studies how viruses spread. Cowling found that infections were most often spread in settings where masks aren’t worn.

“Masks work. But even with mandatory masking, you still need social distancing as well,” he says. You can lower your risk by avoiding crowds. Crowds increase the risk of coming in contact with someone who has COVID-19.

What to Look For

Common symptoms of COVID-19 include fever, cough, headaches, fatigue, and muscle or body aches. People with COVID-19 may also lose their sense of smell or taste. Symptoms usually appear two to 14 days after being exposed to the virus.

But even people who don’t seem sick can still infect others. The CDC estimates that 50% of infections are spread by people with no symptoms. While some with this virus develop life-threatening illness, others have mild symptoms, and some never develop any.

Catching the virus is more dangerous for some groups of people. This includes older adults and people with certain medical conditions. These medical conditions include obesity, diabetes, heart and lung disease, and asthma. About 40% of Americans have at least one of these risk factors.

Getting Treatment

Better COVID-19 treatments mean that fewer people now get severely sick if they catch the virus. Scientists have been working to test available drugs against the virus. They’ve found at least two that can help people who are hospitalized with the virus.

A drug called remdesivir can reduce the time a patient spends in the hospital. A steroid called dexamethasone helps stop the immune systemThe system that protects your body from invading viruses, bacteria, and other microscopic threats. from reacting too strongly to the virus. That can damage body tissues and organs.

Antibody treatments are also available. Antibodies are proteins that your body makes to fight germs. Scientists have learned how to make them in the lab. Antibody treatments can block SARS-CoV-2 to prevent the illness from getting worse. They seem to have the most benefit when given early in the disease.

“Antibody treatments really do have the potential to help people, especially for treating individuals who are not yet hospitalized,” says Dr. Mark Heise, who studies the genetics of viruses at the University of North Carolina at Chapel Hill. Heise is working to develop mouse models to test treatments and vaccines.

Studies are now testing combinations of treatments. “Combining drugs that target both the virus and the person’s immune response may help treat COVID-19,” says Heise. Scientists are also looking for new drugs that better target the virus.

A Shot of Hope: Vaccines

It used to take a decade or more to develop a new vaccine. In this pandemic, scientists created COVID-19 vaccines in less than a year.

The first two vaccines approved for emergency use are from Moderna and Pfizer/BioNTech. Moderna’s vaccine was co-developed with NIH scientists. Both are a new type of vaccine called mRNA vaccines. mRNA carries the genetic information for your body to make proteins.

The vaccines direct the body’s cells to make a piece of the virus called the spike protein. These proteins can’t cause illness by themselves. But they teach your immune system to make antibodies against the protein. If you encounter the virus later, the antibodies provide protection against it.

The mRNA vaccines now available were shown to be more than 90% effective in large clinical trials. They can cause side effects—such as fatigue, muscle aches, joint pain, and headache. But both vaccines were found to be safe in the clinical trials.

“Get vaccinated. The vaccines are safe. They’re incredibly effective,” says Dr. Jason McLellan, an expert on coronaviruses at the University of Texas at Austin. McLellan’s research was critical in developing these vaccines. His team, along with NIH scientists, figured out how to lock the shape of the spike protein to make the most effective antibodies.

As the pandemic has gone on, new versions of the virus, or variants, have appeared. “We’re all very confident that vaccines will continue to work well against these variants,” McLellan says. “Vaccination also helps stop the development of new variants, because it provides fewer opportunities for the virus to change as it replicates.”

Many people will need to be vaccinated for the pandemic to end. Fauci estimates that 70% to 85% of the U.S. population will need to be vaccinated to get “herd immunity.” That’s the point where enough people are immune to the virus to prevent its spread. That’s important because it protects vulnerable people who can’t get vaccinated.

“It is my hope that all Americans will protect themselves by getting vaccinated when the vaccine becomes available to them,” Fauci says. “That is how our country will begin to heal and move forward.”