Mutant virus, vaccination ... I want to know now, new corona `` risk for children '' | Business Insider Japan

As of June 20, the total number of vaccinations for the new coronavirus vaccine in Japan exceeded 30 million.

From June 21, occupational vaccination (using Moderna's vaccine) is expected to begin in earnest, mainly in large companies and universities with many employees, and vaccination not only for the elderly but also for the younger generation. I have also found a path towards

However, Pfizer's vaccine, which is being inoculated in Japan, is for those aged 12 and over. For the Moderna vaccine, you must be 18 or older. In the future, how should we protect children who have not been approved for vaccination in the first place, or whose turn to be vaccinated under the existing framework is difficult?

Mutant virus, etc. to Dr. Saki Ikeda, deputy representative of the project "Kobi Navi" of medical professionals who promotes accurate information dissemination about the new coronavirus and vaccines, and the Department of Pediatric Infectious Diseases at Baylor College of Medicine Texas Children's Hospital. I questioned how the risks to children have changed in the midst of the emergence of

*The interview was conducted on June 10, and is based on the information at that time.

Dr. Saki Ikeda, deputy representative of Kobinavi, Department of Pediatric Infectious Diseases, Texas Children's Hospital, Baylor College of Medicine.

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What is the infection risk for children?

—— Are there any characteristics of infection routes in children?

Ikeda: "Splash infection is the main focus" is the same for children and adults.

"Contact infection", where you touch (an object with a virus) and get infected through mucous membranes, is possible, but the rate is low. Also, in places where the 3Cs overlap, infection can occur through micro droplets (fine droplets produced when coughing or sneezing).

Also, as a characteristic of the place of infection, children are often infected at home. It is an infection from an adult who brought the virus, especially from a guardian. School infections do occur, but are relatively rare.

For elementary and junior high school students, infection is mainly at home.

Source: Ministry of Education, Culture, Sports, Science and Technology ``Hygiene Management Manual for New Coronavirus Infectious Diseases at Schools''

—— At nursery schools, there are many cases where many children are crowded together in a small space. Why are there relatively few infections in such places?

Ikeda: I'm not sure.

Of course, there are rare cases where children are infected at nursery schools, but I think there are more patterns of infection from adults such as nursery teachers to children. However, many nursery schools have strict infection control measures such as masks and hand disinfection, so many infections are prevented.

On the other hand, once it is brought into the home, there is no way to prevent it. If you find out that you are infected, you need to take measures such as wearing a mask and reducing contact, but I think there are limits because we live together.

—— From the beginning of the epidemic, it has been said that ``young people and children have mild symptoms even if they are infected.'' Do you know the reason?

Ikeda: Unfortunately, I don't know for sure. There are various hypotheses.

For example, the new coronavirus is taken into cells by sticking to the surface of human cells with protrusions called "spike proteins" on the surface of the virus. In children, the ``part where the virus sticks'' (ACE receptor) in the respiratory tract appears differently from that in adults, or the virus is effectively eliminated by white blood cells attacking the virus directly (natural immunity). There is also a theory.

Children are less likely to have underlying diseases such as obesity, high blood pressure, and diabetes, which are factors that aggravate COVID-19. not.

——Isn't it possible to say that the factor that "children are less likely to become seriously ill" is a factor that prevents the spread of infection among children? It seems that the more severe the symptoms, the stronger the ability to transmit the virus.

Ikeda: There are cases where the amount of virus released by asymptomatic people is quite large, but it is true that the relative number of infections from people with strong symptoms is higher.

Of course, you have to consider the bias that "(people with symptoms) are well researched" to some extent.

—— Is it difficult to grasp the trend?

Ikeda: Especially in Japan, many cases of confirmed infection in children are found as close contacts (of infected adults). The actual situation of infection can only be investigated from such data at hand, so it is difficult to honestly grasp the actual situation (mild or asymptomatic infection).

However, there are studies that estimated how many children were actually infected by examining how much antibody was in the blood.

In the United States, the CDC (Centers for Disease Control and Prevention) has reported the results of a blood survey of children under the age of 18 after the summer peak of 2020 in Mississippi. The study found that the proportion of children under the age of 18 with antibodies to COVID-19 was no different than adults (ages 18 to 49).

How does the mutated virus affect children?

GettyImages/d76 masahiro ikeda

—— Recently, there is concern about the spread of the delta strain, which is said to have first occurred in India, even in Japan. I've heard rumors that the delta strain makes children more susceptible to infection, is that true?

Ikeda: I don't think I can say for sure. Looking at reports from India and the UK, we know that the overall infectiousness is increasing. It may be that the number of infected children is relatively increasing as the number of infected people increases.

According to a report by the Ministry of Health, Labor and Welfare, among the people (about 750,000 people) who have been confirmed to be infected with the new coronavirus (to date), about 10% of the total are children (under the age of 10). about 80,000 people).

I couldn't find any specific data on the delta strain, but there are reports that the alpha strain was slightly higher than this (about 10%), mainly in facilities where children gather, depending on the region. there was.

However, in London, alpha strain infections are not common in children, and the ratio of infected adults and children has not changed significantly before and after the emergence of the mutant strain. (reference)

—— Some people say that the delta strain is more likely to become seriously ill, is that true?

Ikeda: There are initial reports from England and Scotland that ``the risk of hospitalization is higher with the delta strain than with the alpha strain,'' but I think it is important to accumulate further epidemiological data.

Of course, the more important thing is to limit the spread of infection and prevent the creation of mutated viruses.

Don't forget "vaccination" even in Corona

GettyImages/takasuu

——Infectious diseases are not limited to corona, but there are many. What are “dangerous infectious diseases when children get infected”? How risky is the new coronavirus compared to such infections?

Ikeda: There are many infectious diseases that become severe when children are infected. Globally, low- and middle-income countries still have high mortality rates for children under the age of five from infectious diseases. Among them, there are many infectious diseases that can be prevented with the power of vaccines.

Basically, children under the age of 1 (infants) have a higher risk of severe respiratory viral diseases due to narrow airways (airways) and immature immunity.

For example, "whooping cough" is a common cold that causes a mild cough in adults, but it can be severe and fatal in children in the first few months of life. However, it can be prevented by vaccination.

In addition, rotavirus, which is common in children, can cause gastroenteritis, dehydration, and aggravation.

I remember seeing many children with gastroenteritis at the hospital around 2010, when rotavirus vaccine had not yet become a routine vaccination in Japan. Some children became so severe that they needed intravenous drips, some were dehydrated enough to be hospitalized in the intensive care unit, and others developed acute renal failure.

In both the United States and Japan, the number of people who do not want to go to the hospital due to the epidemic of the new coronavirus is increasing, and regular vaccinations are being delayed. Those are the problem.

—— How far should we take infection control measures such as disinfection? Many people say that if you do too much, your baby's hands will be rough and pitiful.

Ikeda: Yes. As for babies, the center of infection is droplet infection, so when disinfecting with alcohol, it is necessary to dry the alcohol thoroughly so that the child does not lick it. Also, don't push yourself too hard.

It is very important that adults take proper infection control measures and do not bring the new coronavirus into the home.

Suppress the points of infection control and pull out where you can cut corners. I'm sure there are some people who continue to disinfect their homes, but since the infection is mainly droplet infection, the CDC recommends disinfecting frequently touched surfaces about once a day unless there is an infected person in the home. I am listing.

——Continue to the new corona, aftereffects and vaccines

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(Text: Takashi Mitsumura)