COVID-19 basics

What is COVID-19 (formerly known as the novel coronavirus)?

COVID-19 refers to the human infection caused by the new coronavirus strain, SARS-CoV-2. There are several coronaviruses already known to infect humans and animals such as bats, camels, cats, and more. Human infections caused by coronaviruses usually result in a mild upper respiratory infection (such as the common cold). Prior to COVID-19, two other coronaviruses (SARS, MERS) were known to cause more serious lower respiratory infection (pneumonia). COVID-19 is a new virus strain that is believed to have originated around the city of Wuhan, China, and started spreading among people in late 2019.

When did the first case of COVID-19 occur in the United States?

The first U.S. case was announced Jan. 21, 2020, in Washington state.

What is the source of the outbreak?

We know that the closest coronavirus relatives of this current virus are all harbored in Asian bats and it is most likely that the virus was recently introduced into the human population from an animal source in China. Initial cases appear to be linked to a live food market in Wuhan, China. Investigations are ongoing to determine the virus' source and mode of transmission.

Why is this virus so dangerous? Why are people worried?

People are very worried as this is a new infection and there is a lot we do not know about it. It is dangerous because it is new, so no humans have had any prior infections with it, therefore no one is immune to it. Although most cases are mild, given our global population, even a small percentage of significantly ill people results in a much higher burden of patients requiring hospital care. 

Is COVID-19 a pandemic?

Yes, there is broad global spread of COVID-19, consistent with a pandemic. 

Can the pandemic be stopped?

The COVID-19 infection has spread globally at this time. The burden of infection suggests a large proportion of people will contract the infection before we have a capacity to slow, or stop, the current transmission. 

Will warmer weather kill the virus?

No one knows for sure. We do know that there's a cold and flu season, and approximately 15% of colds are caused by one of the coronaviruses. People tend to get fewer colds in the summer, so there's a chance that warmer weather and more sunlight might slow the spread of this new virus.

What do experts know so far about the severity of the illness caused by COVID-19?

Most reported cases have been mild (similar to a cold). However, some cases have resulted in severe pneumonia that requires patients to spend time in a hospital, and a small proportion of victims have died. We currently do not know enough about the illness to predict who will develop more severe disease, but current data indicate that older age and underlying disease (COPD, diabetes, immunosuppression, etc.) may be risk factors.

Why is there so much attention on COVID-19 when influenza kills thousands every year?

New diseases, because of some degree of ambiguity, always generate more concern. We don’t pay as much attention to illnesses such as influenza – even though it results in 25,000 to 50,000 deaths per year in the U.S – because we know what to expect and have become used to the yearly influenza epidemics.