State of COVID-19 infections like a 'bomb with a lit fuse': Japanese medical expert

TOKYO -- The surge in coronavirus infections in Japan has shown no signs of abating during the past few weeks, despite the national government's request that the public take thorough countermeasures to contain the virus's spread. Hidekazu Nishimura, head of the Virus Research Center at Sendai Medical Center in northeast Japan, who is an expert on infectious diseases, has warned strongly about airborne transmission of the virus, whose risk increases during the winter. The Mainichi Shimbun asked Nishimura about the current state of infections, the correct way to use masks, and how he evaluates the suspension of the government's "Go To Travel" subsidy program aimed at reviving the pandemic-hit tourism sector.

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Mainichi: COVID-19 infections have surged since late November, and the number of patients with severe symptoms has also increased. The so-called "win-or-lose three weeks" in battling the virus, as the government described it, ended on Dec. 16, but infection trends appear to remain unchanged. How do you view the current situation?

Hidekazu Nishimura: The winter spread of infections is as predicted. I think that Japan has been holding out against an explosive spread of the coronavirus, in comparison to countries in Europe and the United States, but we are by no means in a position to view the situation optimistically. To make an analogy, the current situation is like a bomb with a lit fuse hissing. The health care system has become strained, and will possibly rupture if no countermeasures are taken.

M: Why do infections spread more easily in the winter?

N: Particles that come out of people's mouths when they cough or breathe contain proteins, among other substances, as well as water droplets. Such particles that are suspended in the air, called "aerosol" particles, tend to get tinier in dry conditions. As temperatures and humidity levels are high in the summer, it takes longer for the particles to dry out, and they are dispersed in the atmosphere while they are still large. So in many cases, the particles rarely enter the body, or linger in upper airways, including the nose and throat. In such cases, there is the possibility that even if individuals are infected, they will have only mild symptoms such as a head cold or have no symptoms at all.

Meanwhile, the low humidity and quick drying of particles in the winter means the particles become smaller in a shorter period of time. Therefore, the aerosol is dispersed over a wider range, increasing infection risks, and the particles can easily enter into deep areas of the lungs as they are small. In such a scenario, the disease develops in the lungs, increasing the risk of severe symptoms.

Besides this, there are factors including increased opportunities to be in a confined and enclosed environment amid cold weather in the winter, as well as a decline in a function of the throat that removes foreign substances due to coldness and dryness. In summary, infections spread during the winter, and it's a scary season in which people are prone to developing severe symptoms.

M: For countermeasures against infection in the winter, what's something that we should especially be wary of?

N: That would be airborne transmission, where infections occur as aerosol containing pathogens suspended in the air are inhaled. Aerosol contains droplets dispersed when people cough, as well as droplet nuclei formed when the droplets dry. Because of this, when focusing on the state of pathogens, airborne transmission is also called aerosol transmission. As mentioned earlier, aerosol particles are smaller during the winter, and are dispersed across a wider range than the normal distance of 1 to 2 meters, thereby increasing infection risks.

As the World Health Organization (WHO) and other institutions initially did not significantly recognize the possibility of the COVID-19 virus being transmitted through the air, 239 virologists worldwide, including myself, issued a declaration in July, demanding that countermeasures placing weight on airborne transmission be taken. Following this, the WHO and the U.S. Centers for Disease Control and Prevention (CDC) officially recognized airborne transmission of the novel coronavirus.

M: How can airborne transmission be prevented?

N: Airborne transmission can be prevented by avoiding the "three C's" of confined spaces, crowded places and close contact settings, and wearing masks correctly. As rooms are often closed off with heaters on during the winter, ventilation is important to avoid the three C's. However, when the room temperature drops all of a sudden due to ventilation, there is potential danger of heat shock, in which blood pressure changes drastically, triggering diseases of the heart and blood vessels. Even in regular times, there are many deaths caused by heat shock in the winter, and it defeats the purpose if people lose their lives while taking countermeasures against infection. It is necessary to take sufficient precautionary measures, such as opening windows a bit while using the heater, so that the room temperature does not fall too much.

It is important to wear masks properly so that there are no gaps, and that they don't slide off. There are "experts" who say things like, "You mustn't touch the surface of masks as they have viruses on them," but this is wrong. If your face gets covered by droplets directly from infected individuals on-site in the health care field, viruses may stick to your mask, but it is unlikely for such a situation to occur in your normal daily life, and it is unnecessary to heed such warnings. When your mask is displaced from its original position even in the slightest, you can take defensive measures by adjusting it back to its original position frequently, and holding it in place by using your hand at times.

M: There are people who use mouth and face shields instead of masks. What do you think about this?

N: I do not recommend their usage. This is because neither of them can prevent the infiltration of aerosol particles; nor are they useful in self-protection. Furthermore, mouth shields are originally for preventing saliva droplets from getting on food products, and cannot prevent the spread of tiny aerosol particles that play a role in infections. If their length is short, face guards could draw in particles from coughs of nearby people and allow wearers to breathe them in instead, which could possibly raise infection risks.

In Japan, value has been placed on preventing contact transmission, or infection spread through touching the nose, mouth or other body parts with a contaminated hand that has touched pathogens. The countermeasures of washing hands and disinfection have also been emphasized. But contact transmission is not so common. There are people who have developed something like an obsessive-compulsive disorder, being unable to do anything without disinfection even when it comes to packages of food products, but there is no need to fear infection to that extent.

M: The Japanese government has advised people to wear masks during dining gatherings except for when putting food in their mouths. How do you evaluate this?

N: When meeting with others, I won't say that it's meaningless to wear masks as much as possible, but I can only view it as deskbound discussion. Can we actually dine with others in such a way in reality? Dining gatherings are supposed to be opportunities where people enjoy conversations while eating. If people do not talk at all when they have their masks off, the conversation is broken off midway, and loses tempo. The suggestion lacks a sense of humanity, and is comical when I imagine such scenes. I don't like it. If the government is going to make such a proposal, it might as well order the public to not dine out with others.

M: Prime Minister Yoshihide Suga indicated his intention to continue the "Go To Travel" subsidy campaign, aimed at spurring pandemic-hit industries, on the grounds that there is no evidence that infections spread as a result of the program. However, the prime minister did a 180 and decided on Dec. 14 to suspend the tourism subsidy program across the country for the year-end and New Year's holiday.

N: Scientifically, I think it is difficult to prove that the "Go To Travel" program led directly to a spread of infections, and it's also difficult to prove that it wasn't a factor that caused the spread. However, as many people remember the national government requesting the public to reduce contact with others by 80% when the state of emergency was issued, it is only natural for people to have the impression that infections will increase if they move around, and they will regard administrative measures that try to move people proactively as contradicting such recommendations. However, as winter is a season where infections can spread easily, I think that it is possible that this is the biggest cause of infections, and I do understand the national government's assertion that it needs to keep the economy rolling.

The problem is that the method taken by the national government is not consistent. If the government really thinks that continuing the subsidy program is for the good of the public, it wouldn't need to change this decision even if the approval rating fell. The policy change that came immediately after the fall in approval ratings appears merely as a bid for popularity, and the public's distrust will likely also deepen. This goes for the simultaneous closure of schools across Japan in March as well. Why does the government decide on such significant things in such a haphazard manner?

M: In your recently released book, titled "Shingata corona: Tadashiku osoreru" (Fearing the novel coronavirus correctly), you point out the significance of tending to the needs of individuals in vulnerable positions in society.

N: What I fear is that people who suffer and die from causes other than COVID-19 infections will increase. Elderly people and those with disabilities who receive welfare services have not been able to receive care due to staff shortages amid the spread of the novel coronavirus, and individuals who had worked diligently have lost their jobs and are struggling to get by to the point where they cannot secure meals. In more severe cases some even take their own lives. It is certainly necessary to take coronavirus countermeasures and prevent a collapse in health care, but in addition to this, a system that protects socially vulnerable individuals should be arranged properly.

M: Vaccines have been developed, and are being administered in Britain and the United States. There have been a number of people who showed intense allergic reactions. What should we be careful of when conducting vaccinations in Japan?

N: It is important for the national government to provide data to the Japanese public and accurately explain the merits and demerits of getting a vaccine in advance. The government should use data from countries like the United States and those in Europe where vaccinations have already begun, and disclose information on the rate of side effects, as well as health abnormalities that occur coincidentally around the same timing as inoculation, but are not side effects of the vaccine. It should also let people know how effective vaccinations are and what kind of demerits could arise if individuals don't get vaccinated. And then, if members of the Japanese public could determine whether they should get the vaccine or not, the situation would be ideal. The Japanese government must also prepare ways to pick up on side effects swiftly, as well as relief measures in the event those side effects occur.

(Japanese original by Hiromi Makino, Integrated Digital Nsews Center)