Childhood Vaccination Schedule in the United States
アメリカでの小児予防接種スケジュール
Vaccination and Children's Health （予防接種リサーチセンター）
日本国内での予防接種スケジュール（英語版）
Vaccination schedule in Japan (English version)
Hepatitis B Virus
This virus causes hepatitis when it enters the body, and can cause cirrhosis and liver cancer when it becomes chronic or carrier.
The virus can be transmitted from a mother with hepatitis B to her child during childbirth, through blood contaminated with the virus, or through sexual intercourse.
Hepatitis causes fatigue and jaundice. Symptoms are often very mild.
Hepatitis can rapidly become very serious. It is called fulminant hepatitis and can be life threatening.
Hepatitis B vaccine prevents this disease.
The WHO (World Health Organization) instructs that the vaccine be administered as a routine national vaccination as soon as the child is born.
In Japan, vaccination is given from 2 months of age.
Vaccination is optional for children over 1 year of age.
Rotavirus
Rotavirus causes gastroenteritis with diarrhea and vomiting in children.
In severe cases, the body loses water and salt, resulting in dehydration.
If dehydration becomes severe, the child must be hospitalized and given intravenous fluids.
The disease is highly contagious and is prevalent in daycare centers.
The number of hospitalizations due to rotavirus infection has decreased since the vaccine became available.
Rotavirus vaccine is taken by mouth to prevent the disease.
The World Health Organization (WHO) considers rotavirus vaccine to be one of the most important vaccines.
It can be given at 6 weeks of age and is administered in 2 or 3 doses at 4-week intervals.
This vaccine is not available to children who have previously had intussusception.
Rubella (German measles)
This is a disease caused by the rubella virus that causes acute fever and rash.
After an incubation period of about 2 to 3 weeks, fever occurs, lymph nodes in the neck swell, and a red rash appears on the body. Fever lasts for 3 to 4 days, but some people do not have a fever.
Rubella encephalopathy occurs in 1 in 6,000 children.
Children can contract rubella from the age of about one year old. Most adults are only mildly affected, but severe cases are possible.
It is highly contagious, and even today, rubella is frequently prevalent in Japan.
The most important point to be aware of is infection during pregnancy. If a woman is infected in the early stages of pregnancy, her fetus is at risk of being born with hearing loss, cataracts, heart disease, or other disabilities (congenital rubella syndrome: CRS).
If the father has not received the vaccine, he may pass it on to the baby during pregnancy.
The MR (measles-rubella combination) vaccine prevents this disease.
Two doses are given at the age of 1 year. In addition, two more vaccinations are administered within a year until the child enters elementary school.
Measles
Measles is a highly infectious disease caused by the measles virus that can lead to life-threatening complications.
After an incubation period of 10 days, the infected person develops symptoms similar to those of the common cold, such as fever, runny nose, and cough.
A red rash appears on the body on the third or fourth day of fever, and white patches called “Koplik's spots,” which are characteristic of measles, appear in the mouth. High fever lasts for 7 to 10 days.
Even after the fever has subsided, children may not go to school until three days have passed.
Measles can be serious at any age. It is especially serious during pregnancy.
Due to the low vaccination rate in Japan, outbreaks can occur with viruses brought into Japan from overseas.
Bronchitis, pneumonia, and encephalitis occur in about 30% of the population. Many people die from pneumonia and encephalitis.
The MR (measles-rubella combination) vaccine is used for prevention.
If you are vaccinated, you are less likely to become seriously ill even if you do contract the disease.
The MR (measles-rubella combined vaccine) is administered twice a year, once at the age of 1 and once before entering elementary school.
Adults can also contract the disease. Parents must also be vaccinated.
Chickenpox
This is a highly infectious disease caused by the varicella-zoster virus.
After an incubation period of two to three weeks, fever and a red rash appear, which blisters after one day and spreads throughout the body. The rash becomes blistered after one day and spreads over the entire body, with intense itching. The fever subsides in a few days and the blisters improve in about 7 days.
High fever may persist.
It is more likely to be severe in children before the age of 1 year and in children 7 to 10 years of age and older. It can cause encephalitis and pneumonia.
It can be prevented with the chickenpox vaccine.
One dose is given as soon as the child reaches their first birthday.
A second dose is given 3 months after the first vaccination.
Adults who have not been vaccinated or who have not had chickenpox should receive two doses of vaccine.
Japanese Encephalitis
This disease is endemic around Japan, the Philippines, India, and Southeast Asia.
It is transmitted when mosquitoes that have sucked the blood of pigs infected with the virus suck human blood.
Most people infected with the disease do not show symptoms, but in rare cases, encephalitis occurs. It can cause convulsions and disorientation, resulting in disability or even death.
It can be prevented with the Japanese encephalitis vaccine.
Two doses are administered at age 3, with an additional dose at age 4. Thereafter, one dose is administered after the age of 9.
Mumps
An infectious disease caused by the Mumps virus, in which both or either parotid glands become swollen after an incubation period of 2 to 3 weeks. Infection does not cause fever in some cases. In rare cases, serious complications such as aseptic meningitis, deafness, and encephalitis may occur, so it is important to prevent mumps by vaccination.
Mumps is prevented with the mumps vaccine.
One dose is given at the age of 1 year, and a second dose 2 to 6 years after the first dose.
Most developed countries provide two doses of the vaccine.
Tuberculosis
Tuberculosis is transmitted when an infected patient coughs or sneezes and inhales the spreading tubercle bacilli.
Symptoms at first resemble those of a cold, but children under 3 to 4 years of age are more susceptible to severe disease, especially those under 1 year of age. Pulmonary tuberculosis and meningitis may develop.
Outbreaks can occur in schools and workplaces.
It used to be the number one cause of death among Japanese.
It is prevented by the stamped BCG vaccine. The standard vaccination schedule is from 5 to 8 months of age. In some areas, it is given as a mass vaccination.
Some developed countries with few tuberculosis cases have stopped giving the BCG vaccine.
Recently, tuberculosis and whooping cough have been seen in people of parents' age, so if the cough persists for a long time, please be sure to see a doctor.
Polio
Polio is a disease transmitted by the poliovirus.
Most cases of infection with this virus do not cause illness or only cold-like symptoms. In rare cases, severe cases can cause paralysis of the hands and feet, resulting in motor disability.
The prevalence of poliovirus in the world is decreasing. However, it is still prevalent in South Asia and Africa.
The pentavirus vaccine (diphtheria, pertussis, tetanus, polio, and Hemophilus influenzae type b) is used to prevent poliomyelitis. Three doses are given every 4 weeks starting at 2 months of age. The fourth dose is given 6 to 18 months after the third dose.