Measles infection is spreading in the country.

Measles is extremely contagious, and when it develops, it can become severe and life-threatening.

It summarizes the latest infection status, symptoms characteristics, and what to do if infection is suspected.
(As of May 5)

The number of infected people in Tokyo exceeds last year for the first time in three years

On April 4, a man in his 27s in Ibaraki Prefecture who returned from India was confirmed to be infected.
Ibaraki Prefecture called for caution by announcing the Shinkansen vehicle that the man rode on and the medical institutions he used.

Later, a woman in her 30s and a man in his 40s in Tokyo who were on the same bullet train were confirmed to be infected.

This is the first time in three years since 2020 that an infection has been confirmed in Tokyo.

According to preliminary figures released by the National Institute of Infectious Diseases on May 3, the number of infected people this year is 23 as of May 5.

In 14, when the census began, the number of measles infections reached 7,1 due to a large-scale epidemic in Japan.

However, in 2008, the number of cases was reduced to 1, and all of the cases were imported from overseas, so the Japan was recognized by WHO = World Health Organization as being in a "state of exclusion" for measles.

In 1013, there were a series of reports of measles infections, and it was reported that 2015 people were infected in one year, but since the spread of the new coronavirus infection in 35, the level has been low due to the decrease in the movement of people to and from overseas, and it was 2019 cases in adults (1) and 744 cases last year (2020).

The number of infected people has already exceeded last year's number as of May.

Extremely contagious "measles"

The reason why measles requires vigilance is that it is extremely contagious and can become seriously ill or cause death.

Measles is a viral infection that is transmitted by inhaling the virus in particles released by a patient coughing or sneezing.

In addition to airborne infection, it can also spread through droplets and contact, and it is extremely infectious, and if you are not immune, you will almost certainly be infected just by being in the same room as an infected person.

If the people around you are not immune and no countermeasures are taken, the "basic reproduction number" that indicates how many people to spread the infection from one patient is "1 to 12", and it is said that it is much more infectious than the new coronavirus, which has been said to be about "18 to 2".

In April, infection was confirmed in a person who was riding in the same car on the Shinkansen, and in 3, a part-time clerk was confirmed to be infected at a commercial facility in Osaka, and the infection spread to shoppers who were visiting the sales floor.

Expert "The possibility of infection just by being together in the same place for a short time"

Dr. Kaoruko Taya, director of the Kanagawa Prefectural Institute of Public Health, who has been working on measles countermeasures at the National Institute of Infectious Diseases, said, "It is a highly contagious disease that can become infected just by being together in the same place for a few minutes or for a short period of time."

There are also cases of severe illness and death

The main symptoms of measles infection include fever, cough, and rash.

According to Project Professor Tetsuo Nakayama of Kitasato University, who is familiar with measles, the fever is characterized by going down in about two days and then rising again, rising to nearly 2 degrees Celsius, and the fever lasts for about a week.

Also, since the rash does not appear until a few days after the symptoms begin to appear, it may be difficult to identify it as measles at first.

In addition, there are cases where pneumonia and encephalitis are caused as complications of infection and become severe.

In particular, encephalitis occurs in about 40 in 1,1000 people, and in some cases, death.

"There is no silver bullet for measles."

According to the CDC = Centers for Disease Control and Prevention in the United States, 1000 to 1 out of 3,<> children infected with measles will die from respiratory and nervous system complications.

Since there is no silver bullet for measles and treatment is based on symptoms, experts say it is important to prevent infection with vaccines and other means.

In 2007, the infection spread mainly to children aged 0 to 1 who had not been vaccinated in Japan, as well as teenagers and 1s who had only received one dose.

Experts also caution that in middle-aged and elderly people who have not experienced infection and have not been vaccinated or have only received one dose, infection can be life-threatening.

Project Professor Nakayama said, "The most serious complication of measles is encephalitis, which is an initial symptom in which a person does not respond to calls out when he has a fever and rash. I want people to recognize that there is no silver bullet and that this is a disease that should not be underestimated."

If you suspect that you are infected, you should contact a medical institution and see a doctor.

Pregnant women should be especially careful

Women who are pregnant should be especially careful.

If a pregnant woman is infected with measles, there is a high risk of complications, and the possibility of miscarriage or premature birth has been pointed out.

In addition, the vaccine to prevent infection is a "live vaccine" that weakens the virulence of the virus, and it is not appropriate to receive it if you are pregnant.

In order to prevent measles, it is important to get vaccinated in advance.

However, even if you get vaccinated without realizing that you are pregnant, the risk is considered low.

Severe encephalitis that develops after many years

About five years after measles is cured, 5 in 10,1 people may develop a disease called subacute sclerosing panencephalitis (SSPE).

SSPE develops after a long incubation period due to infection with the measles virus that has been latent in the central nervous system. Even though you were living well, you may suddenly be unable to perform daily activities, abnormal behavior may become noticeable, and you may die.

According to the National Institute of Infectious Diseases, it is common to become infected with the measles virus before the age of 2 and develop it around the age of 4 to 8 years after an incubation period of 6 to 10 years, but there are also cases of measles in adults.

Dr. Taya points out that "it is important to prevent measles infection by getting vaccinated."

Be careful not to get infected when traveling abroad Contact before seeing a doctor

The incubation period from infection with the measles virus to the onset of the disease is 10 to 12 days.

The spread of measles has been reported in Southeast Asia and other countries, and it is possible that it can be infected while traveling abroad and develop after returning to Japan.

When you have symptoms such as fever, cough, or runny nose, especially when you suspect measles and visit a doctor, it is important to call the medical institution or public health center in advance and give instructions instead of visiting a medical institution without contacting them.

In addition, the Ministry of Health, Labour and Welfare has urged people to refrain from using public transportation if they have symptoms that suspect infection.

Measles can be prevented with vaccines

Measles can almost certainly be prevented by vaccination.

In Japan, free routine vaccination of the measles vaccine based on the Immunization Act began in October 1978.

After that, it was found that immunity could be weakened by only one vaccination at the age of one, and since June 10, the "MR vaccine" to prevent measles and rubella has been used, and it is administered twice, once at the age of one year and one year before entering elementary school.

According to Project Professor Nakayama, two doses of the vaccine are more than 1% effective, and immunity lasts almost a lifetime.

Currently, a combination vaccine for measles and rubella is being administered.

According to the package insert of the vaccine,
the side reactions after vaccination are listed as ▽ fever is "1% or more" to "2006.6%",
▽ rash is "1% or more", although it varies depending on
the manufacturer.


A survey of 1.2 million people from 2 to 95, when they were vaccinated against measles alone, found that 5% to 28% had a fever and 3% to 5% had a rash.

In addition, there were two people who developed encephalitis, but according to Project Professor Nakayama, it is unlikely to be related to vaccines, such as the detection of genes of a different type of virus than vaccines.

According to the Ministry of Health, Labour and Welfare and the National Institute of Infectious Diseases, the vaccination rate for measles at the age of one has been continuously above the target of 1984% since fiscal 2008, but has fallen to 440.10% in fiscal 20.

The Ministry of Health, Labour and Welfare says that it seems that there were people who could not receive vaccination due to the pressure of medical institutions and public health centers due to the influence of the new corona, and refraining from visiting medical institutions.

For this reason, the Ministry of Health, Labour and Welfare has operated so that if vaccination cannot be administered during the period of regular vaccination due to the influence of the new coronavirus, it can be treated in the same way as regular vaccination even outside the period, and requires local governments to call for vaccination together with those eligible for regular vaccination.

"Get vaccinated now."

Director Taya is concerned about the drop in vaccination rates by several points.

"If a child fails to receive the vaccine at the age of one, he will not have the opportunity to get vaccinated until before entering elementary school, and if this vaccination rate continues, about 1,5 children will not receive the measles vaccine every year, which is a critical situation that will have a major impact on society as a whole. If the infection spreads, there may be a shortage of vaccines, so I would like you to get vaccinated now."

If you don't know if you have been vaccinated, take an antibody test.

It is generally thought that people in their 50s and older have never been vaccinated.

Since then, people in their 1s to 1990s born before April 4, 1 are believed to have received one dose as a child, and those born on or after April 33, 40 are eligible for two doses.

Some people are not vaccinated as children for some reason.

A reliable way to check vaccination history is to check with the Maternal and Child Health Handbook.

If you cannot check your Maternal and Child Health Handbook, you can also take an antibody test to find out.

Also, if you are infected with measles, such as a child, you may have antibodies.

You can find out if you tell your family clinic or local internal medicine that you want to check for measles antibodies.

It takes about one week to know the results, and the cost is several thousand yen, but it is certain.

If antibodies are not enough, even adults should be vaccinated.

Experts emphasize, "If you don't know your vaccination history, get tested now."

In addition to measles antibodies, we also recommend that you examine rubella, mumps, and chickenpox antibodies. And if the antibodies are not enough, we recommend that even adults get vaccinated.

The Ministry of Health, Labour and Welfare (MHLW) recommends that people who have never had measles and have not had the opportunity to receive two doses of measles, especially those who are at high risk of contracting measles, such as medical personnel, child welfare facility staff, and school staff, who have a significant impact on others, and who plan to travel to endemic countries, should consult their primary care physician and consider getting vaccinated.

Expert: "Reaffirming the horror of measles"

(Project Professor Nakayama)
"We don't know where and who can get measles, there is no cure, it can be life-threatening, and it is very important to prevent it with a vaccine. Considering that you can be infected with measles, the side effects of the vaccine are not severe, and I think the benefits are quite high when applied to measles. The number of measles patients is decreasing, and the fear of natural transmission is diminishing, but I want people to reaffirm the horror of measles."