Some outlandish rumors about COVID-19, the disease caused by the new virus SARS-CoV-2, still persist, and continue to percolate on the internet: To some, it’s a dastardly bioweapon designed to wreak economic armageddon on the West; a left-wing conspiracy to damage the reelection prospects of President Trump; a virus that leaked from a Wuhan laboratory.

Such paranoid speculation is at the very least unhelpful, health professionals say, and only serves to politicize a global public-health emergency and distract from potentially life-saving measures to contain and/or slow the spread of coronavirus. After reportedly jumping from animals to humans at a food market in Wuhan, China in early December or before.

“ Conspiracy theories politicize a public-health emergency and distract from potentially life-saving measures. ”

As the world struggles to come to terms with the prospect of COVID-19 changing the way we socialize and work, people are left wondering whether the financial markets have had a massive overreaction to yet another virus that will eventually fizzle out, or whether it’s time to buckle down and heed warnings of the disease’s seriousness issued by governments and health authorities. Here, MarketWatch breaks down the facts and fiction of the global pandemic.

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Is coronavirus airborne like measles?

Airborne transmission is “plausible,” according to a study published in the print edition in the peer-reviewed The New England Journal of Medicine last month from scientists at Princeton University, UCLA and the National Institutes of Health. The researchers concluded that the virus could remain airborne for “up to 3 hours post aerosolization.”

The scientists found that SARS-CoV-2, the virus that causes the new disease COVID-19, was detectable in the air for up to three hours, up to four hours on copper, up to 24 hours on cardboard, and up to two to three days on plastic and stainless steel. For those reasons, officials recommend washing hands, cleaning surfaces and “social distancing” in public spaces.

It’s recommended that you remain at least six feet apart from other people, especially indoors, experts say. “Studies have looked at how far spit and little droplets fly, and that’s the magic number,” said Luis Ostrosky, vice chairman of internal medicine at McGovern Medical School in Houston.

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Will you be OK if you are young and healthy?

“The COVID-19 virus is capable of causing infection and severe disease in all people of all ages,” said Dr. Maria Van Kerkhove, head of WHO’s emerging diseases and zoonosis unit. “The data that we’ve seen from a number of countries is that the majority of children that are infected are experiencing mild disease,” she said, adding that there has been a handful of childhood fatalities.

While there’s no question that the elderly and those with underlying conditions have been affected much more than other age group, younger people are not immune: 20% of deaths in Korea were people under the age of 60, and 15% of people in intensive care units in Italy were under 50 years of age, said Dr. Michael Ryan, WHO’s top emergencies expert.

In New York state, where 50% of the U.S. cases are located, Gov. Andrew Cuomo, a Democrat, said last week that roughly half of hospitalized coronavirus patients were between 18 and 49. Among the latest fatalities: A 36-year-old public school principal from New York City — where there were more than 3,048 deaths from coronavirus as of Monday morning.

How long can it live in your bathroom?

“It’s not certain how long the virus that causes Coronavirus survives on surfaces, but it seems to behave like other coronaviruses,” the World Health Organization said. “Studies suggest that coronaviruses — including preliminary information on the COVID-19 virus — may persist on surfaces for a few hours or up to several days.”

Higher temperatures, based on earlier coronaviruses, are likely to degrade it. But experts caution that — as spring arrives in the Northern Hemisphere, which usually marks the end of the traditional flu season — this novel coronavirus may not necessarily go away in warmer weather. It is from a different family of viruses than the flu, and it is highly contagious.

Its life span will also vary, depending on the type of surface, temperature and/or humidity. Bathrooms are a welcoming environment for coronaviruses. “Previous coronaviruses can remain viable in cold, moist surfaces up to nine days,” Ostrosky said. So if you are sharing a home with someone who has coronavirus, he strongly advises against sharing the same bathroom.

President Trump speaks in an address to the nation from the Oval Office at the White House on Wednesday. He announced a suspension in travel from Europe to the U.S. Associated Press

Will recirculated air on a plane make me sick?

In-flight oxygen is probably of higher quality than the air in your home. “If you have an infected person in the front of the plane, and you’re in the back of the plane, your risk is close to zero simply because the area of exposure is thought to be roughly six feet from the infected person,” according to Charles Chiu, professor of laboratory medicine at University of California, San Francisco.

“Ventilation rates provide a total change of air 20 to 30 times per hour,” the WHO says. “Most modern aircraft have recirculation systems, which recycle up to 50% of cabin air. The recirculated air is usually passed through HEPA (high-efficiency particulate air) filters, of the type used in hospital operating theatres and intensive care units, which trap dust particles, bacteria, fungi and viruses.”

President Trump last month said he was “marshaling the full power of the federal government” by suspending travel for non-U.S. citizens from Europe to the U.S. for 30 days, later extending it to the U.K. and Ireland, a measure aimed at stopping sick people spreading COVID-19. “We made a lifesaving move with early action on China. Now we must take the same action with Europe,” he said.

How COVID-19 is transmitted

Are men more affected by this than women?

“Men do tend to be more affected than women and their symptoms are often more severe,” Ostrosky said. “Estrogen has a protective effect. When scientists block estrogen production in animals, they become more susceptible to coronaviruses and they get worse symptoms.” He added, “But please don’t take estrogen injections or pills. If you are a man, they will not help you.”

In Italy, the average age of those who have died from COVID-19 in Italy is 80.3 years old, and only 25.8% are women, according to Silvio Brusaferro, legal representative at the Istituto Superiore di Sanità. Italy also has the oldest population in Europe. But U.S. health professionals also warn that people in their 20s, 30s and 40s, and up have been hospitalized with COVID-19.

Is there a gender difference when it comes to influenza? “No, with the flu it’s pretty even,” Ostrosky said. The two illnesses have similar symptoms, including a sore throat and coughing. Coronavirus is a type of virus common in humans and animals, and causes mild-to-moderate respiratory illnesses. But in very severe cases it can travel through your body and damage other organs.

‘Most face masks do not effectively filter small particles from the air and don’t prevent leakage around the edge of the mask when the user inhales,’ the CDC says. MarketWatch photo illustration/iStockphoto

Do face masks guard against coronavirus?

Face masks help prevent patients from spreading the virus, but they are not as effective as protecting the healthy, the Centers for Disease Control and Prevention says. On April 3, it recommended the use of cloth face masks, saying they were useful for preventing the wearer from passing on the virus if he/she was asymptomatic. It reversed that stance, citing “new evidence.”

Some previous studies have concluded that face masks have helped reduce contagion by reducing droplets being sprayed into the air during flu season; another Japanese-based study says this works when paired with vaccination, not an option in this case. it may be that they work in a small amount of cases and/or just wearing them helps to promote healthy behaviors.

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This study says N95 medical-grade masks do help filter viruses that are larger than 0.1 micrometers (One micrometer, um, is one millionth of a meter.) The coronavirus is 0.125 um. “These products can help block large droplets expelled by the wearer, but also have been shown to have efficacy at filtering smaller particles and are designed to fit tightly to the face,” it said.

Face masks are needed for health-care professionals. N95 masks are tighter-fitting than surgical masks and protect against small particles and large droplets, according to the CDC. Health and Human Services Secretary Alex Azar said that there are only 30 million N95 masks in the national stockpile, and “as many as 300 million masks are needed in the U.S. for health-care workers.”

New York Gov. Andrew Cuomo on Wednesday ordered all New Yorkers to cover their faces in public when they can’t maintain a proper social distance. “You’re walking down the street alone? Great!You’re now at an intersection and there are people at the intersection and you’re going to be in proximity to other people? Put the mask on. You don’t have the right to infect me.”

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Should I visit my grandmother?

No. Seniors have a higher risk of getting severely sick and/or dying from COVID-19. Italy has the oldest populations in Europe, and that’s one reason some observers say it’s had such a high fatality rate. Health professionals say people should remain at least six feet apart from other people because that’s roughly as far as the virus can travel in a cough, sneeze or when someone is talking.

Whether you’re on a plane or a train, you are at risk of contracting coronavirus, especially if you are seated near an infected person and/or you touch a contaminated surface and then your face without properly washing your hands. However, WHO says there’s no difference between sitting in a restaurant, office or movie theater: If you’re near an infected person, you’re at risk.

While you can’t do much about being seated next to an infected passenger on a plane at 30,000 feet, you can exercise responsible “social distancing,” Ostrosky said. “The more people who are in that enclosed space with you, the higher the risk you have of being exposed to someone who is sick,” he added. “If we had to rank them, there is an increased risk in larger groups.”

Does washing clothes protect against the disease?

“The average person should not worry about their clothing,” Sarah Fortune, a professor and chair of the department of immunology and infectious diseases at the Harvard T. H. Chan School of Public Health, told MarketWatch in an email. “If you are a health-care provider and potentially subject to a high density of virus, the answer is different. But for most of us, it is all about our hands and face.”

“Coronaviruses in general last a lot longer on a solid, nonporous surface compared to porous fabrics,” Juan Dumois, a pediatric infectious-diseases physician at Johns Hopkins All Children’s Hospital in St. Petersburg, Fla., said. He suggested they would survive better on “artificial fibers” such as polyester than on cotton.

Health professionals suggest washing your hands after you take off your face mask and gloves, if you’ve touched any surfaces, door handles and/or products in a store. Some health professionals say washing gloves or putting them in a high tumble dryer may also help guard against the virus. Heat at 56°C can help kill the SARS coronavirus and/or alcohol spray.

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Coronavirus update: As of Wednesday, nearly 200,000 of the 614,482 confirmed cases in the U.S. were in New York State. At least 51,056 people in the U.S. have recovered. The U.S has the most confirmed cases of any country in the world and, at 27,760, the most deaths, according to Johns Hopkins Whiting School of Engineering’s Centers for Systems Science and Engineering.

More than one-third of the U.S. confirmed fatalities were in New York City, and they rose by 752 over the last 24 hours. That figure does not include more than 3,000 people who died in New York City and were not tested for coronavirus, but whose death certificates suggested they likely died from an illness related to COVID-19, health authorities in the state said.

Worldwide, there were 2,023,663 million confirmed cases and at least 132,276 fatalities.

(Meera Jagannathan and Elisabeth Buchwald contributed to this article.)

(This story was updated on April 15, 2020.)