CORONAVIRUS UPDATE: As experts learn more about the novel coronavirus, news and information changes. For the latest on the COVID-19 pandemic, please visit the Centers for Disease Control and Prevention.

The SARS-CoV-2 virus began spreading around the world in late 2019, and likely reached U.S. shores by January 2020. By Mar. 11, 2020, the World Health Organization (WHO) declared the novel coronavirus disease (COVID-19) a pandemic. Two days later, the United States declared a national emergency because of the outbreak, according to the Centers for Disease Control and Prevention (CDC).

Suddenly, life as we know it changed. As COVID-19 spread across the country, hospitalizing hundreds of thousands of Americans, much of the U.S. went into lockdown to slow the spread of the virus. Testing facilities were established, and guidelines to stay home and practice social distancing were established.

As of Nov. 8, 2020, there have been more than 10 million confirmed positive coronavirus cases in the U.S. Scientists and researchers worldwide have been working furiously to unfold the mystery of this new infection and the illness it causes. Every day new information becomes available as they learn more. And now—months later—what we know and understand looks different than it did in March. Here are the key coronavirus updates.

Coronavirus update: Key takeaways

“Initially most of our understanding about SARS-CoV-2 was based on past information from similar coronaviruses like SARS, which caused a pandemic in 2002-2003, and MERS, which has been present since 2012,” says Jenny Nelson, DO, a specialist in infectious diseases and internal medicine at the University of Missouri. “Over the last eight months, much research has been done on the novel coronavirus.”

Since March, understanding has grown about:

Transmission: Initially, it was thought that COVID-19 spread through respiratory droplets, living on surfaces for up to 17 days. Now, some research suggests it is airborne, surviving for only 72 hours on surfaces, but with the potential for “super-spreaders” who infect many and asymptomatic spreaders, who never feel sick.
High-risk groups: Initially older adults, the immunocompromised, and those with certain respiratory conditions were seen as most at risk. The list now extends to pregnant women, people with diabetes, and even those who are overweight.
Symptoms: The three original symptoms of coronavirus were shortness of breath, dry cough, and fever. Now symptoms include loss of taste and smell, headache, gastrointestinal issues, eye problems, and skin lesions.
Testing: The U.S. did not have adequate testing available at the start of the pandemic. Now, at-home test kits and antibody testing are widely accessible, though there are some delays in test results nationwide.
Treatment: Many drugs have been tested and found inadequate or even harmful, such as hydroxychloroquine. Two have shown benefits. Veklury (remdesivir) was approved by the FDA to reduce recovery time for hospitalized patients. Dexamethasone may reduce mortality.
Prevention: Initially, public health officials recommended against wearing masks. Now, they are seen as a primary way to protect yourself and others, along with social distancing. Vaccines are underway, but scientists don’t fully understand immunity and how long it lasts.

While understanding of COVID-19 has come a long way. as Dr. Nelson puts it, “We still have a lot to research and a lot to learn about this virus.”

Transmission

When the COVID-19 pandemic was first announced, there were many unknowns about transmission. It was suspected that COVID-19 was spread through respiratory droplets from an infected person—either directly, or from touching a surface then touching your face (also known as fomite transmission). Headlines and early studies showed that the coronavirus could live on surfaces for up to 17 days.

“In the beginning, people were concerned and asking, ‘Where is it?’” says Jan K. Carney, MD, MPH, the associate dean for public health and health policy at the Larner College of Medicine at the University of Vermont. There was widespread fear the virus lurked on every door knob or faucet.

A more recent study by the National Institutes of Health found that the coronavirus can survive on a variety of different surfaces for only up to 72 hours depending on the material:

In aerosols, for up to three hours
On copper, for up to four hours
On cardboard, for up to 24 hours
On stainless steel and plastic, for up to three days

Though, some research shows that it can last longer at certain temperatures. While possible, the risk of fomite transmission is fairly low. Of bigger concern? Emerging research shows that airborne transmission of COVID-19 may be the primary way the virus spreads. Meaning, in addition to large droplets expelled when you talk, laugh, cough, or sneeze, smaller aerosols that can travel farther and stay in the air longer may be responsible for most infections. This type of transmission allows for super spreader events, when one infected person can transmit the virus to many other people after spending several hours in an enclosed space.

Additionally, people without symptoms can be carrying the virus and spread it to others without ever feeling sick. “The discovery of asymptomatic transmission is a fundamental rationale behind wearing face coverings,” Dr. Carney says. “Universal masking doesn’t [just] protect you; it protects everyone who might be in six feet of you.”

High-risk groups

The groups considered to be most at-risk have changed. Initially older adults, the immunocompromised, and those with certain respiratory conditions were seen as high risk. The CDC revised guidelines on Nov. 2, 2020, to include adults of any age with the following medical conditions:

Cancer
Chronic kidney disease
COPD (chronic obstructive pulmonary disease)
Heart conditions such as heart failure, coronary artery disease, or cardiomyopathies
Immunocompromised state (weakened immune system)
Obesity (body mass index [BMI] of 30 or higher)
Severe obesity (BMI of 40 or higher)
Pregnancy
Sickle cell disease
Smoking
Type 2 diabetes mellitus

The following conditions might increase risk:

Asthma (moderate-to-severe)
Cerebrovascular disease (affects blood vessels and blood supply to the brain)
Cystic fibrosis
Hypertension or high blood pressure
Liver disease
Neurologic conditions, such as dementia
Overweight (BMI of 25 or higher)
Pulmonary fibrosis (having damaged or scarred lung tissues)
Thalassemia (a type of blood disorder)
Type 1 diabetes mellitus

Early on, it was believed that children were not at risk, but that has changed. Children who have obesity, medical complexity, severe genetic disorders, severe neurologic disorders, inherited metabolic disorders, congenital (since birth) heart disease, diabetes, asthma and other chronic lung disease, and immunosuppression due to malignancy or immune-weakening medications are now believed to be at increased risk for severe illness from COVID-19 compared to other children.

“We’ve learned a lot about children—they are not getting as sick, but that isn’t 100% foolproof, as medical conditions play a huge role in the severity of infection,” Dr. Carney says. “It’s important to know who is at risk and who will require hospitalization or die with infection so that we can better protect ourselves and them.”

Symptoms and incubation period

Early in the coronavirus pandemic, symptoms of COVID-19 were believed to look a lot like a cold or the flu. “Fever, cough, and respiratory symptoms were expected—but then we learned that there are some unusual symptoms,” Dr. Carney says. Diarrhea and a sudden loss of taste and smell were recognized as COVID-19 symptoms by the CDC. Currently, the full list of symptoms includes:

Fever or chills
Cough
Shortness of breath or difficulty breathing
Fatigue
Muscle or body aches
Headache
New loss of taste or smell
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea

Rare symptoms may also include skin lesions (sometimes called COVID toes), and eye problems that resemble pink eye. The CDC recognizes that symptoms may appear two to 14 days after exposure to the virus. Or they may not appear at all. It was discovered during a COVID-19 outbreak at a nursing home in Washington that a high proportion of those within the home tested positive without ever experiencing symptoms—and were transmitting the virus. Several other studies have confirmed asymptomatic transmission of COVID-19.

Testing and diagnosis

Initially, the U.S. did not have enough tests to track early transmission and understand how the virus was spreading. There were scams for at-home testing and treatments (which you should still be wary of!). Testing has become more available—but there are still challenges depending on your location. “Our testing capacity, while remaining relatively high, has been hindered by prolonged wait times to receive results in many areas,” Dr. Nelson says.

There has been a huge collaboration to make more COVID-19 testing available faster, but the availability of testing for communities varies since decisions about testing are made by state and local health departments and healthcare providers.

Diagnostic tests

According to the CDC, the only test you can receive to determine whether you are currently infected is a viral test. Viral tests check samples from your respiratory system, such as a swab from the inside of your nose, to check for active SARS-CoV-2, the virus that causes COVID-19. Results from point-of-care tests may be available at the testing site in less than an hour. Other tests must be sent to a laboratory for analysis, a process that takes one to two days once received by the lab—though many labs cannot handle the volume of tests, which may delay results for up to two weeks.

Antibody tests

One other test—an antibody test—is also available to test your blood and determine whether or not you have been previously infected with the virus. However, experts don’t currently know if those who have been infected (and developed antibodies) could be infected again.

Treatments and vaccine status

There is currently one FDA-approved treatment for COVID-19—and another drug that is showing promise.

Remdesivir

Remdesivir is a broad-spectrum antiviral medication that was originally developed to treat Ebola. It was approved by the FDA on Oct. 22, 2020, to treat hospitalized patients with COVID-19. Remdesiver has shown to decrease recovery time.

Dexamethasone

“Also, medical professionals are using dexamethasone—a steroid that may improve mortality from COVID-19,” Dr. Nelson explains. “Thus far we have not had issues with dexamethasone availability, but this may become a problem in the future depending upon how frequently it is used.”

Convalescent plasma

Many hospitals use convalescent plasma, blood donated by those who have recovered from infection, to treat critically ill patients. The data regarding this treatment option is favorable.

There are other drugs being studied as potential treatments, including EIDD-2801, Recombinant ACE-2, monoclonal antibodies, interferons stem cells, anticoagulants, and Favilavir. Hydroxychloroquine—the controversial drug that made headlines as a potential treatment—is no longer viewed as a potential treatment and the FDA stopped its emergency use authorization of it.

Vaccine status

The Department of Health and Human Services and the Department of Defense announced on Jul. 22, 2020, a $1.95 billion deal with Pfizer to acquire 100 million doses of its vaccine candidate as part of Operation Warp Speed—the Trump administration’s push to have a coronavirus vaccine widely available by January. On Aug. 14, 2020, the administration executed a contract for distribution.

The CDC estimates a limited amount of vaccines may be available before the end of 2020, but it’s unknown when the vaccine will be available for widespread use. “One of the areas we don’t understand well enough is how long immunity to an infection can last,” Dr. Carney says. There is some evidence that antibodies fade within months of infection with COVID-19, but researchers are hopeful that T cell responses may provide lasting protection against the virus.

RELATED: Coronavirus vaccine update

Prevention

One thing that hasn’t changed since day one of the pandemic is this: Practicing good basic hygiene (like washing your hands frequently) is critical to prevent infection. The CDC initially recommended against wearing masks. The organization has since reversed course and now recommends wearing a mask along with social distancing more than six feet of everyone in close contact are critical to slow transmission and prevent infection. That includes social get togethers and travel. Staying home is the best way to avoid the spread of COVID-19. If you do socialize, the safest way is in small groups, outside.

What should you expect during subsequent waves of COVID-19?

In July 2020, the United States topped its own daily COVID-19 cases recorded multiple times—with more than 63,000 new cases being reported in a single day. Now in November, cases have reached new record levels in the country — exceeding 120,000 new cases reported in a single day..

You can track total case counts and latest updates on cdc.gov and the total deaths here.

And although there is so much more that we know compared to March 2020, there are still many unknowns and there is no cure or vaccine for COVID-19. That’s why Dr. Carney emphasizes to lean on what we do know: “We know enough to protect ourselves and our communities and we need to continue to stay vigilant in wearing facial coverings and maintaining social distance. We need to emphasize prevention.”