In an era of online shopping and global shipping, some NPR listeners have written to us with this question: Am I at risk of catching the new coronavirus from a package I receive from China?
Almost certainly no, according to the Centers for Disease Control and Prevention.
"Because of poor survivability of these coronaviruses on surfaces, there is likely very low risk of spread from products or packaging that are shipped over a period of days or weeks at ambient temperatures," the CDC concludes in its Q&A.
Infectious disease specialists we spoke with were even more definitive.
"It's not going to be transported on a box," says Dr. Michael Ison of Northwestern University, who studies viral infections among transplant patients, who have weakened immune systems.
Coronaviruses are thought to mainly spread from person to person via respiratory droplets, researchers say. And, so far, the novel coronavirus seems to have spread only among people who were in close personal contact.
While there's still a lot unknown about this particular coronavirus, experts have a sense of what to expect, based on experience with previous strains that have led to outbreaks of serious illness, such as SARS and MERS.
"There is no evidence from any previous outbreak that anyone has ever gotten infected from a package," Elizabeth McGraw, director of the Center for Infectious Disease Dynamics at Pennsylvania State University, tells NPR.
McGraw says it is highly unlikely that the virus could survive for multiple days outside or inside a cardboard box, for example, that contains something an infected person had sneezed on or handled.
"What we know about these viruses is that they don't last very long on surfaces, and that's particularly the case for a very porous surface" such as cardboard, McGraw explains.
Some viruses do survive longer than others — and conditions such as temperature, humidity and surface material can influence how long a virus lives, explains Dr. Amesh Adalja, a senior scholar with the Johns Hopkins University Center for Health Security, whose work focuses on emerging infectious diseases. But many viruses outside the host fall apart within hours in the natural environment.
"Shipping conditions of most products are going to be not conducive to the virus remaining viable," Adalja told NPR's Goats and Soda team earlier this week.
In other words, Adalja concludes: "I don't think it's a real risk."
DAVID GREENE, HOST:
As of this morning, there are 11 confirmed cases of coronavirus infections in the United States. The most recent are in California, including the second instance of person-to-person transmission in this country. The Department of Homeland Security is expanding precautionary measures at U.S. airports. Flights carrying people who have been in China in the last two weeks are being diverted to one of 11 airports where they will be screened carefully.
RACHEL MARTIN, HOST:
A mandatory quarantine for travelers returning from the hardest hit areas of China also went into effect Sunday night. So far, there have been no deaths here, but in China, more than 17,000 people have been diagnosed and more than 360 people have died from the coronavirus.
GREENE: With a story that's moving so quickly, we've been getting a lot of questions from you about the virus, and our co-host Noel King spoke with NPR's Health correspondent Allison Aubrey to try and get you some answers.
NOEL KING, BYLINE: OK. So here's the first question that we got from a listener that may have a little frustration in it.
ALLISON AUBREY, BYLINE: Sure.
KING: This person writes, on the one hand, we hear reports that the flu has killed more people, and then on the other hand, we hear the U.S. needs to prepare for the spread of this new coronavirus. They sometimes seem like conflicting reports about how much we should worry - and I'll add, what we should worry about.
AUBREY: Well, right now, without a doubt, I'd say the most immediate health threat to almost everyone listening right now is the flu. I mean, every year, millions of people get the flu. It leads to thousands of deaths a year - somewhere between 12,000 and 60,000 deaths on average just here in the U.S.
So by contrast, in the U.S. so far, there have been no deaths from the new coronavirus. It has not spread widely in the U.S. That could change. But it's important to note that both the flu and the new coronavirus are respiratory illnesses, which tend to spread in similar ways. So when an infected person sneezes or coughs on another person or surface, the virus spreads.
KING: So how do you stop it from spreading?
AUBREY: Well, one very effective thing you can do - it sounds so obvious - wash your hands.
KING: (Laughter) Yeah.
AUBREY: Right? Infectious disease expert William Schaffner of Vanderbilt University told us you just cannot underestimate this step.
WILLIAM SCHAFFNER: The hand-washing for sure - constantly, frequently, all the time.
AUBREY: And that's because touching your hand to a contaminated surface then touching your eyes, your nose, your mouth, it's a very common route of transmission. It's how the virus infects you. Other ways to prevent the spread - you know, cover your cough, sneeze into an elbow, things we teach our kids, if only we adults could remember to do them.
KING: Let me go back to the flu for a second...
KING: ...Because the flu death statistics are really surprising.
KING: The Center for Disease Control estimates that at least 8,000 people have died from the flu this flu season in the United States alone...
AUBREY: That's right. Mmm hmm.
KING: ...Which led to another listener question - how deadly is the new coronavirus?
AUBREY: At this time, the virus appears to be much less lethal than other coronaviruses that have led to outbreaks. Back in the early 2000s, there was the SARS outbreak, which had about a 10% mortality rate. More recent years, there was the MERS, the Middle East respiratory syndrome, outbreak. The death rate there was a little over 30%. Now, so far, the estimate mortality rate for this novel coronavirus is between 2% and 4%.
KING: That's a much lower death rate.
AUBREY: That's right. And several infectious disease experts I've spoken to say the death rate may be even lower, given that officials have not identified everybody who has been infected. I mean, early on in an epidemic like this, you test the people who are really sick. So of course, you're missing all those people who may have mild cases or people who have the virus but aren't symptomatic.
KING: Some of our listeners had questions about prevention beyond just wash your hands and try not to cough on people.
KING: One listener wrote in and said, I recently received a package in the mail that I ordered from China. Could I catch the virus from it?
AUBREY: Well, in this era, when we order so much online, our listener is not the only person asking this question. It came up during a CDC press conference. And Nancy Messonnier, the CDC point person on coronavirus had this response.
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NANCY MESSONNIER: In general, because of the poor survivability of these coronaviruses on surfaces that's sort of in the range of hours, there is likely a very, very, very low - if any - risk of spread from products or packaging that is shipped over a period of days or weeks at ambient temperatures.
AUBREY: So you hear her there saying, never say never, but practically speaking, the virus is likely only able to survive several hours. So there is no evidence that the package from China that you've just got in the mail could infect you with the coronavirus.
KING: Another thing a lot of people asked about is masks. We've been hearing on air...
KING: ...There's a shortage of masks in China. People want to know - should I go out and buy a mask in the event that the virus spreads here?
AUBREY: Sure. Generally speaking, masks are not terribly effective. We spoke to infectious disease expert William Schaffner about them.
KING: The evidence is really rather scanty that the general population will benefit by the use of masks.
AUBREY: Hey says, basically, they just can't completely stop germs from spreading.
KING: People who wear surgical masks, even those who put them on appropriately, still breathe a substantial amount around the edges of the mask; hence, you could still transmit this virus.
AUBREY: And that's why he emphasizes the importance of good hygiene habits, like hand-washing, as we just discussed.
KING: All right, so there's a question here about vaccines. We know there's no coronavirus vaccine yet.
AUBREY: That's right.
KING: But one listener asked if the pneumonia vaccine could help protect against the coronavirus.
AUBREY: Yes. Indirectly, the pneumonia vaccine could possibly be beneficial. So let me explain this - people who get respiratory infections are extra vulnerable to secondary bacterial infections. So the immune system is so busy or distracted fighting off the virus it can't defend as well against bacteria. In fact, for a little historical perspective, it was actually bacterial pneumonia that caused most of the deaths during the 1918 flu pandemic.
So the pneumonia vaccine is recommended for people 65 and older, for smokers and for people with certain medical conditions. And by fending off the pneumococcal bacteria, the vaccine can help prevent these sometimes deadly infections that accompany respiratory illnesses.
KING: NPR Health correspondent Allison Aubrey. Thanks so much, Allison.
AUBREY: Thanks for having me.
(SOUNDBITE OF LYMBYC SYSTYM'S "KUBRICK") Transcript provided by NPR, Copyright NPR.