NHK World’s Ebara Miki sat down with him on April 8.
Ebara: Yesterday [April 7], the Japanese government declared a state of emergency for areas heavily affected by the virus, including Tokyo and Osaka. How will this work?
(On April 16th, the government decided to expand the areas to nationwide.)
Kawaoka: Under current laws, the government cannot force people to stay home or penalize them for not doing so. But in a state of emergency, it can request businesses, including shops and restaurants, to close.
There were differing opinions within the advisory panel about the timing of the declaration. My opinion has always been that we need to warn people not to get close to each other in public spaces, whether or not we declare a state of emergency. I’ve already noticed there are fewer people on the streets so I think they’re getting the message for now.
Ebara: What have you learned so far about the new coronavirus?
Kawaoka: It’s a very interesting virus. There are many different kinds of coronaviruses. They infect and cause diseases in different species. Some cause respiratory infections, others cause peritonitis. This one infects people and causes respiratory infection. But we don’t know exactly why young people seem to be more resistant. People older than sixty are facing more severe symptoms. We also know this virus is highly transmissible. If you stand more than 6 to 7 feet away from an infected person, you can avoid infection. But if you stand close to an infected person and talk, you’re more likely to get infected. The virus is in the air when you talk, even if you can’t see any droplets.
You should also be careful of items that may have been contaminated by saliva or spit. There was a two-day concert at a club in Osaka in mid-February. On the first night, an infected person spread the virus to a few people. On the second night, the infected person wasn’t there but someone still got infected. Something had been contaminated by the person’s saliva or spit and the virus survived for 24 hours.
Ebara: Where did the virus originally come from? And how did it jump to humans?
Kawaoka: The virus originally came from bats. The exact same type of virus hasn’t been found, but there are many similar bat coronaviruses, so that’s where it must have come from. What we don’t know yet is whether there was an intermediate host between bats and humans, or if the virus jumped directly to humans.
Ebara: What stands out about this coronavirus when compared to SARS, MERS and other influenza viruses?
Kawaoka: Influenza viruses have been around us, as far as we know, for the last 150 years. People have some immunity to influenzas, even to new influenza viruses. When we say new influenza virus, we mean that the surface is new, but the internal portion is the same or very similar to viruses that have already circulated. So we’re immune to new influenza viruses, at least to some extent. But this isn’t the case with the new coronavirus.
Ebara: When the outbreak emerged in Wuhan, did you expect the virus to spread so quickly?
Kawaoka: Well, it didn’t register with me until mid-January when I read a paper that said a group of researchers went into Wuhan for surveillance on January 3rd. Surveillance is what researchers do to conduct epidemiological studies. You don’t do that unless a viral infection is spreading. It later became known that the infection was already widespread in Wuhan by late December. But I didn’t notice anything until mid-January. Japan didn’t stop flights to and from China at that point, and that was clearly something we could have done to stop the virus. Lots of people visited Japan from China during the Chinese Spring Festival.*
(*The Chinese holiday season started on January 24th).
Some of those travelers were infected and spread the virus. That’s how the outbreak started in Hokkaido. And the Snow Festival* amplified the infection. It could have been prevented. It was very unfortunate.
(*An annual festival in Hokkaido’s largest city of Sapporo. It attracts more than 2 million visitors over just one week. This year, it was held as scheduled starting on February 4.)
Ebara: The virus arrived in Europe and America at around the same time as Japan. But this country didn’t see an explosive spread of infection until late March. Why was this the case?
Kawaoka: Our infectious diseases experts were trying to identify and stamp out small clusters. Initially, they were identifying clusters and contacting everyone who was in touch with an infected person. By doing so, they were able to contain the virus and they found out that around 80% of infected people don’t actually transmit the virus. This was a very important piece of information. It meant you don’t need to trace every single person who’s been infected if you can trace the cluster. If you do nothing, the cluster will grow out of control. But as long as you identify a cluster small enough to contain, then the virus will die out. And that was Japan’s initial strategy. And the virus, as introduced from China, was contained.
But the number of cases started to increase as travelers started to return from Europe and the United States. After that, it became difficult to contain.
Ebara: Has the coronavirus mutated? Is the original virus that emerged in Wuhan different from the one seen, for example, in Europe?
Kawaoka: That’s a very important question. First of all, the virus that caused the Wuhan outbreak was already highly transmissible. Since then, it has spread and we know there have been slight mutations as it replicated. But we don’t know yet whether there are any differences in terms of transmissibility and pathogenicity caused by the mutations. As far as mutations are concerned, in comparison to various influenza viruses, this one is surprisingly stable.
Ebara: Over the course of the 21st century, people seem to have been focused only on the benefits of globalization and perhaps overlooking the risks of free and fast movement of people. I know experts like you have been warning about a potential pandemic for years but do you feel like most people overlooked the possibility, forgetting about what happened in the past, like with the Spanish flu?
Kawaoka: That’s human nature, we can’t prevent that. People forget, memories are short. That’s why we have wars. People place a priority on the economy and other things. This pandemic may also be forgotten soon after it’s over.
Ebara: Which aspects of the virus do you want to learn more about?
Kawaoka: A lot. I want to learn how we can more effectively grow the virus so we can make vaccines in large quantities. Also, we need to learn how we can attenuate, how we can cripple the virus, so we can make a vaccine that infects people but doesn’t cause disease and also mounts immunity. We need to know how to make the virus less pathogenic.
I also want to learn why and how this virus causes disease. If we know that, we can prevent the disease. There are lots of things we need to learn.
We should be able to have a good vaccine ready in several years. But I don’t believe what’s often said, which is that one can be produced in a year or so* because it’s very important to ensure that a vaccine is safe. There are always side effects, but you don’t want any severe ones. If a vaccine causes severe side effects, then that makes the vaccine worthless because people don’t trust it.
(*The WHO says a vaccine may be ready within 12-18 months.)
Ebara: How long does it take for us to get back to normal life?
Kawaoka: At least three years for the whole world. We’ll be doing this, repeating the restriction of movement and then easing it. Restrictions won’t be continuous, but this virus will remain in the population, somewhere in the world. It’s going to take a long time for a good size of people to obtain immunity. And until then, we’re not out of the woods.
What we’ll do for at least the next couple of years is what we’re doing right now—restrict movement and contain the virus to an extent that allows us to return to relatively normal life. And if the virus is reintroduced, we resume those restrictions. By this time, I hope we’ll at least have a good drug to treat the virus, so we can prevent severe cases.
Ebara: Tell me about the Spanish flu pandemic.
Kawaoka: Back then, some countries or cities did what we’re doing now—restricting the movement of people. There were two waves of infection in 1918: the spring wave and the winter wave. During the winter wave, some countries had movement restrictions, but others didn’t. There was massive death, but those who were infected and survived obtained immunity. The following year saw another outbreak, where more people got infected and at the same time, the virus became less pathogenic. We don’t know whether the same thing will happen with the coronavirus or not.
Ebara: What’s the most important thing you want to tell people around the world?
Kawaoka: Stay home. Stay safe. You can avoid infection by staying away from infected people. It’s a very simple way to protect yourself. If you don’t get close to an infected person, you will not get infected. The new coronavirus is more complicated than the Ebola virus, which is transmitted only through direct contact. The coronavirus can be transmitted through droplets. So, stay home. And if you go out, wash your hands. The virus is sensitive to soap and alcohol. Wash your hands with regular soap. It will kill the virus.