There are so many stories swirling about the coronavirus, it’s hard to tell what’s fact or fiction. People have been holed up for weeks obsessively staring at computer screens — sifting through conflicting and confusing advice about how to stay safe and treat the virus.

Time for a reality check. Here’s what the most credible authorities — the World Health World Health Organization, the Centers for Disease Control and Prevention and the National Institute of Allergy and Infectious Diseases — know and are still learning about the virus.

How did coronavirus start?

A person probably got it from an animal, but health officials aren’t sure.

“The first human cases of COVID-19 were identified in Wuhan City, China in December 2019. At this stage, it is not possible to determine precisely how humans in China were initially infected,” according to the World Health World Health Organization.

“It is thought that [it] jumped the species barrier and initially infected humans…this could be a domestic animal, a wild animal, or a domesticated wild animal and, as of yet, has not been identified,” the organization said.

How long does coronavirus last on surfaces?

Somewhere between a few hours and multiple days, according to the WHO.

“It is not certain how long the virus that causes COVID-19 survives on surfaces, but it seems to behave like other coronaviruses. Studies suggest that coronaviruses may persist on surfaces for a few hours or up to several days,” the organization said.

To clean the surface, wash it “with a simple disinfectant to kill the virus and protect yourself and others,” the WHO advises.

Can you catch coronavirus from packages?

It’s unlikely that a package sent to your home — including grocery deliveries or other supplies — would be carrying the virus, according to the WHO.

“The likelihood of an infected person contaminating commercial goods is low and the risk of catching the virus that causes COVID-19 from a package that has been moved, traveled, and exposed to different conditions and temperature is also low,” it states.

Do face masks work against coronavirus?

Authorities still don’t know if masks help a healthy person outside of a medical setting avoid catching the virus. The CDC is investigating.

“The idea of getting a much more broad, community-wide use of masks outside of the health care setting is under very active discussion at the task force. The CDC group is looking at that very carefully,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, said earlier this week.

Other health officials recommend wearing one only if you’re already sick.

“Only wear a mask if you are ill with COVID-19 symptoms (especially coughing) or looking after someone who may have COVID-19. Disposable face masks can only be used once,” the WHO advises.

Can dogs get coronavirus?

Yes, but there haven’t been many confirmed cases, and canines are not likely to spread it.

“While there has been one instance of a dog being infected in Hong Kong, to date, there is no evidence that a dog, cat or any pet can transmit COVID-19,” according to the WHO.

The CDC reports that two dogs have been infected, and recommends “avoiding contact with your pet including, petting, snuggling, being kissed or licked” if you are sick and “washing your hands after handling” animals.

Does coronavirus harm mostly old and sick people?

Yes, it appears to hit those demographics hardest.

A CDC study showed that around 80 percent of coronavirus deaths were among adults 65 years and older. People with “severe chronic medical conditions — like heart disease, lung disease and diabetes, for example — seem to be at higher risk of developing serious COVID-19 illness,” the CDC said.

Still, many young people have been seriously ill. The CDC also reported that about 20% of hospitalized patients were between the ages of 20 and 44.

What are coronavirus symptoms?

It usually starts with a cough or a fever.

“The most common symptoms of COVID-19 are fever, tiredness, and dry cough,” according to the WHO. “Some patients may have aches and pains, nasal congestion, runny nose, sore throat or diarrhea. These symptoms are usually mild and begin gradually. Some people become infected but don’t develop any symptoms and don’t feel unwell.”

Is there a treatment for coronavirus ?

Doctors are testing out several different drugs — including antiviral and antimalarial medicines — but nothing has been scientifically proven to work.

“There is no evidence that current medicine can prevent or cure the disease,” according to the WHO.

How far can coronavirus travel in the air ?

It can travel three to six feet, most officials agree.

“The disease can spread from person to person through small droplets from the nose or mouth which are spread when a person with COVID-19 coughs or exhales. These droplets land on objects and surfaces around the person,” according to the WHO. “People can catch COVID-19 if they breathe in droplets from a person with COVID-19 who coughs out or exhales droplets. This is why it is important to stay more than three feet away from a person who is sick.”

What’s the real death rate?

Health officials are still searching for answers because some infected people are asymptomatic and others were not tested before dying. Last week, the CDC released a report noting that of the 170,000 coronavirus cases reported globally between Feb. 12 and March 16, roughly 7,000 — about 4.1 percent — resulted in death.

Of the 213,144 people infected in the US, 4,513 people have died, or about 2 percent, the CDC said Thursday.