A vaccine is a suspension of weakened disease-causing organisms that are given to a person to stimulate his immune system and thus protect him against the disease caused by the organism. Required vaccines for children entering school vary among states. One state may require certain vaccines that another does not. However, certain vaccines are considered by the American Academy of Pediatrics, or AAP, to be standard for the United States.
Hepatitis B
Hepatitis B, or hep B, is a liver disease caused by the hepatitis B virus. It is associated with chronic liver disease and liver cancer. Pediatrician Jan Drutz, of Baylor College of Medicine, writes in the medical database "UpToDate" that about 250,000 people in the United States contract this virus every year, and that the number of cases increases during the teenage years. Therefore, vaccination against this disease is important. The first dose of the vaccine against hepatitis B is usually given at birth, with the subsequent doses of the hep B series given at ages one to two months and then again at ages six to 18 months.
Pneumococcus
Dr. Elaine Tuomanen, of St. Jude Children's Research Hospital, writes in "UpToDate" that prior to the introduction of the pneumococcus vaccine, the bacteria streptococcus pneumoniae, also known as pneumococcus, was the cause of many serious infections in children, including pneumonia, sinus infection and meningitis, which is a potentially life-threatening infection of the tissue surrounding the brain. Since immunization became universal within the United States, infection with pneumococcus has gone down by 60 to 90 percent in children who are younger than two. There are two types of pneumococcus vaccines: the conjugated pneumonia vaccine and the polysaccharide vaccine. The conjugated vaccine works by attaching a certain type of protein to the part of the bacteria that elicits an immune response: the polysaccharide capsule of the bacteria. The conjugated vaccine is especially good for children younger than two, because at this age, the immune system doesn't respond to the nonconjugated form of the vaccine. The AAP recommends that the pneumococcus conjugated vaccine be given in four doses: the first three doses at age two months, four months, and six months and the last dose between ages 12 and 15 months. Also, for children who are two to five years old, the AAP recommends a follow-up dose if the child did not get all four doses of the vaccine as a baby.
Diphtheria, Tetanus and Pertussis
The diphtheria, tetanus and pertussis, or DTaP, vaccine is a combination vaccine that immunizes children against three diseases. An organism called corynebacterium diphtheriae causes diphtheria, is a serious respiratory disease. The mortality rate associated with this disease is quite high, and the younger the child is, the greater the risk of death. The bacteria clostridium tetani causes tetanus, a disease of the nervous system. This organism produces a toxin that causes the muscles to spasm and contract painfully. The book "Epidemiology and Prevention of Vaccine-Preventable Diseases" reports that among unvaccinated individuals, the risk for death from tetanus increases. Pertussis is also known as "whooping cough" and is especially dangerous in young infants. The combination vaccine, DTaP, as per the AAP, should be given four times: at age two months, four months, and six months and the final vaccination at age 12 months if at least six months have passed between the third and final doses. Otherwise, the final dose should be administered between the ages of 15 and 18 months.
Haemophilus influenzae type b
Haemophilus influenzae type b, or Hib, was once an extremely common cause of meningitis, as well as other infections of early childhood. The AAP reports that this virus may cause pneumonia, joint infections, bone infections and even death. Fortunately, since the introduction of the Hib vaccine, death from infections caused by Hib have become extremely rare. The AAP suggests four doses of this vaccine at ages two, four, and six months, and the final dose at ages 12 to 15 months.
Poliovirus
The poliovirus causes poliomyelitis, also known as polio. Polio was once a significant cause of paralysis and death in young children all over the world. One of the great international public health achievements has been the near-eradication of this disease by ensuring that children are immunized against the virus. Dr. John Modlin, of Dartmouth Medical School, reports in "UpToDate" that at this time, all the countries of the Western hemisphere, Europe, and Pacific regions do not have this virus at all---it has been eradicated. Because polio has such devastating consequences, vaccination is critical. The AAP recommends the inactivated polio virus vaccine be administered. An inactivated virus simply means that a weakened form of the virus is injected to stimulate the body's immune response---the virus is not strong enough to cause polio. The AAP also recommends giving four doses: the first at age two months, the second at four months, the third between six and 18 months, and the final dose at ages four to six years.
Measles, Mumps and Rubella
The measles, mumps and rubella, or MMR, vaccine is a combination vaccine that immunizes against these viruses that cause these diseases. The measles virus can cause an infection that involves a cough, fever, and rash, but can also lead to serious complications such as encephalitis, an infection of the brain. Mumps was once a common cause of a viral syndrome that included fever, aches and lack of appetite, as well as inflammation of the saliva-producing glands under the ears. The rubella virus causes what is known as the German measles. The infection itself is generally mild and often has a widespread rash associated with it. However, if a pregnant woman has rubella and passes it on to the fetus, her child can be born with birth defects such as heart or eye abnormalities or hearing loss. The MMR vaccine should be given twice: once at ages 12 to 18 months and a second time at ages four to six years. If at least 28 days have passed since the first dose, the second dose may be given before the child is four years old.
Varicella
The varicella zoster virus, or VZV, causes chicken pox, one of the once-classic diseases of childhood. It also causes herpes zoster, which is commonly known as shingles. In 1995, the varicella immunization was added to the list of standard childhood immunizations. Dr. Mary Albrecht, of Harvard Medical School, writes in "UpToDate" that this has resulted in a significant decrease in infection and death from this virus. The AAP recommends two doses: one at ages 12 to 15 months, and a second dose at ages four to six years.
References
- American Academy of Pediatrics: Haemophilus Influenzae Type B (Hib) Vaccine: What You Need to Know
- "Epidemiology and Prevention of Vaccine-Preventable Diseases"; M. Atkinson; 2008
- American Academy of Pediatrics; Recommended Immunization Schedule for Persons Aged 0 Through 6 Years; 2010
- "UpToDate"; Denise S. Basow; 2010
