Immunizations are a series of shots that protect children against certain illnesses, many of which are potentially fatal. These vaccines are usually given to children when they are very young and most vulnerable to certain viral or bacterial infections. In some cases, these vaccines provide a lifetime of protection against disease. Other immunizations have to be periodically updated.

The vaccines used in childhood immunizations are made up of tiny amounts of the disease (either in killed or weakened form) that are injected into the body. The immune system perceives these injected microorganisms as a threat and responds by creating antibodies to the disease. These antibodies wait in the body and attack germs when children are exposed to them. The process of establishing antibodies to a disease is known as immunity.

Childhood immunizations usually target 13 diseases, including:

• Hepatitis B (liver infection)
  
  
• Rotavirus (leading cause of severe diarrhea in children)
  
  
• Diphtheria (severe throat infection)
  
  
• Tetanus (serious nerve disease)
  
  
• Pertussis (respiratory illness sometimes known as “whooping cough”)
  
  
• Haemophilus influenzae type b bacteria (leading cause of meningitis prior to vaccine)
  
  
• Polio (virus that can cause permanent paralysis)
  
  
• Pneumococcal infections (lead to ear infections, pneumonia, blood infections and bacterial meningitis)
  
  
• Measles, mumps and rubella
  
  
• Chickenpox
  
  
• Hepatitis A (liver infection)
  
  
• Meningococcal disease (bacterial infection that can lead to bacterial meningitis)
  
  
• Human papillomavirus (sexually transmitted viral infection that can lead to cervical cancer in women)

In addition to these standard vaccines, the Centers for Disease Control and Prevention  and other health organizations such as the American Academy of Pediatrics recommend that all children between the ages of 6 months and 59 months receive the influenza vaccine each year.

Immunizations are a necessary part of keeping children healthy and protected from illness. However, injections often frighten children. Parents are urged to explain to children that it is okay to be afraid, but also to encourage the child to be brave. Parents should also assure the child that they will remain present throughout the procedure.

Immunizations are a series of shots that provide basic protection against certain diseases. The vaccines used in this process contain tiny amounts of the disease – either in killed or weakened form – that are injected into the body. The immune system perceives these injected microorganisms as a threat and responds by creating antibodies to the disease.

Antibodies recognize specific parts of a germ and attack it. Once these antibodies have been created, they are ready to protect the child on any future occasions when the child is exposed to an actual live form of the virus or bacteria. This process is known as developing immunity.

The microorganisms used in vaccines to create antibodies typically are either viruses (e.g., measles) or bacteria (e.g., pneumococcus). In some cases, an organism’s identifying protein or carbohydrate is used. In the past, these vaccines sometimes were delivered through oral solutions, but today they all are given through injections. In addition, there is an increasing tendency to combine vaccines in a single injection.

Young children receive most immunizations, both because many diseases are most prevalent in early childhood and because the immune systems of young children are still developing and may need an extra boost. Most U.S. states require that children receive certain vaccinations before they are allowed to attend daycare, school or camp. However, these vaccines should be given early in life because younger children are more vulnerable to the effects of these infections, which also tend to be more prevalent in younger children.

Immunizations have dramatically reduced the incidence levels of certain childhood diseases. Diseases such as polio, measles, diphtheria, pertussis (“whooping cough”) and tetanus once killed hundreds of thousands of people every year, but now pose very little thereat to people in the United States and most of the Western industrialized world. In the case of smallpox, immunizations have helped to actually eliminate the disease worldwide.

Immunizations can also be used to treat diseases that are contagious, but not life-threatening. These include rubella, chickenpox and mumps. Although these diseases rarely result in fatalities, they may cause complications ranging from hearing loss to sterility (inability to procreate).

Because many diseases have now become uncommon, some parents may no longer feel a sense of urgency about immunizations. Some parents also fear their children will experience side effects associated with these vaccines, or that they will acquire the very disease that the vaccine is intended to protect against.

However, most side effects are mild and easily treatable. Speculation of a potential link between vaccines and other disorders (e.g., autism, attention deficit hyperactivity disorder, sudden infant death syndrome, multiple sclerosis) appears to be unfounded, according to numerous studies that have addressed this question. One vaccine preservative, thimerosal, has been removed or reduced to trace amounts in all childhood vaccines except for the influenza vaccine as a precaution against unnecessary toxic exposure. In addition, a child cannot get a disease from most vaccines, which are made with dead bacteria or viruses. Vaccines that consist of weakened viruses – such as those used to protect against chickenpox or measles, mumps and rubella – occasionally pose a small threat of the child contracting the disease, which then occurs in much weakened form.

It is important that all children continue to have immunizations according to a schedule established by medical experts. This protects not only the child, but all people who have contact with the child. Immunization is not necessary only in cases where a disease has been eradicated throughout the world, such as smallpox. Diseases that no longer are present in the United States – such as diphtheria – could still return because they are present in other parts of the world.

In recent years, the incidence of measles in the United States has increased from less than 2,000 cases annually to more than 50,000. Experts believe this is largely because a reduction in the number of measles vaccinations has allowed the virus to regain a foothold in the population. Another disease that appears to be making a comeback in the United States is pertussis (“whooping cough”). The incidence of the whooping cough has increased from about 1,000 cases each year to more than 25,000. Experts believe this is mostly due as a result of adolescents and young adults not receiving the recommended booster shots. 

The Food and Drug Administration (FDA) tests and approves all vaccines for safety. In some cases, these vaccines almost completely protect a child from disease. In other cases, they protect the vast majority of children who are immunized. Children who are vaccinated yet still become infected usually have a milder form of the condition than those who are not immunized.

Following is a schedule for childhood immunizations:

Immunization can occur in one of two forms. Active immunization involves stimulating the immune system to produce antibodies to fight a disease. This is the form of immunization used in creating vaccines. Passive immunization involves providing an antibody to the patient. It provides only temporary protection against disease. For example, a fetus receives antibodies through the placenta that provide temporary protection against certain illnesses during the newborn’s initial months of life.

Standard childhood immunizations target 13 diseases. Some vaccines provide protection throughout a person’s lifetime, whereas others must be updated after a period of time (such as every 10 years).

The vaccine used to immunize a patient against a disease falls into one of four categories:

• Attenuated live viruses. These are weakened viruses.
• Killed viruses or bacteria. These are dead viruses.
• Toxoid. These contain a toxin produced by a bacterium.
• Biosynthetic. These contain synthetic substances.

All of these vaccines are administered through injections. In many cases, patients will experience side effects. These are typically mild and may include fever and redness or soreness at the injection site, including soreness of the muscle used for the injection. A physician will typically suggest a pain reliever and fever reducer such as acetaminophen to treat such side effects. It should be noted that certain types of nonsteroidal anti-inflammatories (NSAIDs), including aspirin and ibuprofen, which are often used to relieve pain, fever and/or inflammation may react with the immune system in a way that reduces the effectiveness of some types of immunizations including flu shots, according to recent findings. As a result, it is recommended that patients avoid the use of any NSAIDs when receiving any type of vaccination.  

Children who are sick (with the exception of colds or other minor illnesses) should usually wait before receiving a vaccine. In addition, children who have serious allergic reactions during or after an immunization injection should not receive additional doses. Parents are urged to talk to their child’s pediatrician about these circumstances.

Major childhood vaccines and their side effects, if any, include:

• Hepatitis B vaccine (HepB). Protects against hepatitis B, which infects the liver and can lead to long-term problems such as cirrhosis or cancer of the liver. The vaccine is given in three separate injections. The first injection should be given to all newborns soon after birth and before hospital discharge. Infants born to mothers who have hepatitis B should receive the first shot within 12 hours of birth. It is believed that a complete series of hepatitis B immunizations provides protection from the disease over a person’s lifetime. Adolescents and adults should receive these vaccinations if they did not have them as children.
  
  
• Rotavirus vaccine. Protects against rotavirus, a virus that is the most common cause of gastroenteritis in children ages 3 months to 15 months, and the leading cause of diarrhea in children under age 5. Each year, 55,000 children in the United States are hospitalized due to rotavirus infection, according to the Centers for Disease Control and Prevention (CDC). A vaccine for rotavirus (RotaTeq) was approved last year for use in infants under 8 months of age. It is administered orally in three doses, usually at ages 2 months, 4 months and 6 months. Vaccination should not be initiated on babies over 12 weeks old, and the entire series must be completed before the child is 32 weeks (8 months) old. The vaccine is not approved for use in older children. It should be noted that this new vaccine is not associated with Rotashield, the first rotavirus vaccine that was pulled from the market in 1999 because it was linked to intussusception (bowel obstruction caused by the intestine folding into itself). The oral rotavirus vaccine prevents severe rotavirus infection in 98 percent of babies who are immunized, and prevents milder forms in 74 percent of immunized infants.
  
  
• Diphtheria, tetanus and pertussis vaccine (DTaP). Protects against diphtheria (serious throat infection), tetanus (severe nerve disease) and pertussis (respiratory illness sometimes known as “whooping cough”). DTaP is provided in a series of five injections from ages 2 months to 6 years. To protect adolescents against these diseases, a new Tdap (tetanus, diphtheria and pertussis) booster vaccine is recommended at age 11 to 12 years, and for those aged 13 to 18 years who missed the earlier Tdap booster dose. Once the final dosage has been administered, tetanus and diphtheria (Td) booster shots are urged every 10 years. Diphtheria has been eradicated and tetanus has been nearly eradicated in the United States thanks to this vaccine. The vaccine is up to 80 percent effective in preventing pertussis infections.
  
  Mild side effects are common with DTaP immunization, and include mild crankiness, fatigue and temporary loss of appetite. Severe complications are rare, but may include seizure brought on by high fever. Children who are sick (with the exception of colds or other minor illnesses) should delay having this vaccine, and children who have an uncontrolled seizure disorder or neurologic disease may be given a different form that excludes the pertussis part of the vaccine. Children who have certain reactions following administration of the vaccine may not receive subsequent injections. Such reactions include seizures, allergic reaction, breathing difficulties, high fever, shock or collapse, or uncontrolled crying.
  
  
• Hib vaccine. Immunizes patients against haemophilus influenzae type b bacteria, the leading cause of meningitis in children prior to the development of this vaccine. It is given in three doses and a booster from 2 months to 15 months. More than 90 percent of infants who receive at least three doses of the vaccine are protected against meningitis, pneumonia, inflammation of the membrane covering the heart (pericarditis), and certain infections of the blood, bones and joints.
  
  
• Inactivated polio vaccine (IPV). Prevents polio, a virus that can cause permanent paralysis. The vaccine is typically administered four times between ages 2 months and 6 years. More than 95 percent of children who are immunized will be protected against polio, which has been eradicated in the United States thanks to this vaccine. Previously, children often received this vaccine in oral form. Today, it is given almost exclusively by injection, which eliminates the small risk of developing polio that was associated with the live oral vaccine. Older children and teenagers should receive these vaccinations if they did not previously have them.
  
  Children with severe allergies to certain antibiotics including neomycin, streptomycin and polymyxin should not receive this vaccine.
  
  
• Pneumococcal conjugate vaccine (PCV7). Protects against pneumococcal infections, which can lead to pneumonia, blood infections and bacterial meningitis. This infection is spread through direct contact with another person and is most dangerous to children under 2 years of age. Immunizations are given through four injections between ages 2 months and 15 months, and they provide three years of protection. PCV is also given to children who have sickle cell anemia, a damaged spleen, HIV/AIDS and other chronic diseases (e.g., diabetes, cancer) as well as those who are on medications that affect the immune system, including steroids and chemotherapy. Children with these health conditions may also receive the pneumococcal polysaccharide vaccine (PPV) after the age of 2 years.
  
  
• Measles, mumps and rubella (MMR) vaccine. Protects against measles, mumps and rubella (also known as German measles). The vaccine is given in two doses between the ages of 12 months and 6 years. More than 95 percent of children who receive the vaccine will be protected from these diseases. Older children, teenagers and young adults should receive these vaccinations if they did not previously have them.
  
  Side effects include rash, swollen cheeks, febrile seizures (associated with high fever) and mild joint pain. Children may not be good candidates for this vaccine if they have allergies to eggs, gelatin or the antibiotic neomycin; have received gamma globulin; have immune system problems related to cancer, leukemia or lymphoma; are taking corticosteroids or immunosuppressive drugs; or are undergoing chemotherapy or radiation therapy.
  
  
• Chickenpox (varicella) vaccine. Protects against chickenpox, a common childhood illness. The vaccine is now given in two dosages with the first dose administered between 12 months and 15 months of age, and the second one at age 4 to 6. Older children and adolescents who have already received one dose of the vaccine should be given another. Unvaccinated teenagers and young adults may require two doses given one month apart. The vaccine prevents severe forms of chickenpox in 95 percent of those who are immunized, and prevents milder forms in 85 percent of those who are immunized.
  
  Side effects include fatigue and the potential for a rash up to one month after injection. Children may not be good candidates for this vaccine if they have allergies to gelatin or the antibiotic neomycin; have received gamma globulin; have immune system problems related to cancer, leukemia or lymphoma; are taking corticosteroids or immunosuppressive drugs; or are undergoing chemotherapy or radiation therapy.
  
  
• Hepatitis A vaccine (HepA). Protects against hepatitis A, a viral liver infection. The vaccine is nearly 100 percent effective in protecting children from hepatitis A. It is now universally recommended for all children at age 1 year. The HepA immunization is administered in two doses given six months apart. Children not vaccinated at 1 to 2 years of age should be vaccinated during the preschool years. It also is typically recommended for individuals who live in communities with high rates of hepatitis A.
  
  
• Meningitis (MCV4) vaccine. Protects against meningococcal disease, a bacterial infection that can lead to bacterial meningitis. This potentially life-threatening disease involves an inflammation of the membrane that covers the brain and spinal cord. It is highly contagious. The vaccine is given to children at age 11 or 12 as well as to unvaccinated adolescents upon high school entry (age 15), and is especially recommended for youths who will soon enter college and live in a dormitory. The vaccine offers protection for 10 years.
  
  Side effects include headache, fatigue and rash. Children who have a history of allergic reaction to latex should not be given this vaccine.
  
  
• Human papillomavirus (HPV) vaccine. In 2006, the Food and Drug Administration (FDA) approved a vaccine (Gardasil) to protect against several strains of HPV, a common sexually transmitted infection that may cause genital warts in men and women and can infect the cervix in women. Left untreated, HPV in women may lead to cervical cancer. The vaccine is most effective when given before the onset of sexual activity, when a person has not been exposed to HPV. The CDC recommends that the HPV vaccine be routinely given to 11- and 12-year-old girls. However, it can be given to girls as early as age 9 at the discretion of the physician or healthcare provider. It is given in a series of three shots over a six-month period. Although females who have not been exposed to HPV gain full benefits of the vaccine, it offers protective benefits to young girls who have been sexually active and may have been exposed to HPV. For that reason, the CDC recommends that unvaccinated teen girls between 13 and 18 years of age receive the vaccine. 

In addition to these standard vaccines, the CDC recommends that children younger than 6 months of age who have conditions that can cause breathing and swallowing difficulties, such as spinal cord injuries, seizure disorders or other neuromuscular disorders receive the influenza (flu) vaccine each year. The CDC and other health organizations such as the American Academy of Pediatrics also recommend that children between the ages of 6 months and 5 years receive the flu vaccine each year. Children with chronic medical conditions (e.g., asthma, cystic fibrosis, diabetes) and children on long-term aspirin therapy should also receive the influenza vaccine each year. The vaccine can reduce the chances of getting the flu by up to 80 percent during flu season. 

Immunizations are a necessary part of keeping children healthy and protected from illness. However, injections often frighten children. Parents are urged to explain to children that it is okay to be afraid, but also try to encourage the child to be brave. Parents should also assure the child that they will remain present throughout the procedure. It is important for parents to keep a record of all vaccinations a child receives.

When immunizing infants, it usually is helpful for a parent to hold the baby (with the physician’s approval). This will make the child feel more secure. Bringing along a favorite toy or blanket can also help.

Other steps parents can take include:

• Explain why the procedure is necessary. Parents are urged to explain that immunizations will keep the child healthy and free of pain and discomfort in the future.
  
  
• Distract the child during the injection. Distraction techniques include having the child count, singing a song with the child and having the child look away at a picture on the wall or other item.
  
  
• Praise and reward the child. Parents are urged to praise the child after the injection and to plan a fun event – such as a trip to a playground or to the zoo – afterward. This can help make the overall experience more pleasant for the child.

Preparing questions in advance can help patients and parents have more meaningful discussions with their physicians regarding their or their child’s conditions. Parents may wish to ask the doctor the following questions related to childhood immunizations:

1. How should I prepare my child for an immunization?
   
   
2. Will my child experience pain or discomfort during the immunization?
   
   
3. Does my child have a condition that may preclude certain types of immunizations?
   
   
4. If my child cannot be immunized, are there other steps I can take to protect him/her?
   
   
5. What side effects are associated with this type of immunization?
   
   
6. What medications or other treatments should I use if my child develops fever or soreness? Are there any medications I should not give my child after an immunization?
   
   
7. What symptoms might indicate more serious side effects that require a physician’s attention?
   
   
8. Should my child receive an annual influenza immunization?
   
   
9. What are the risks to my child if he/she has one dose of a vaccination, but does not complete the series?
   
   
10. Should my child still be immunized if he or she is older and has not received various vaccinations?
    
    
11. Will my child be at risk of developing autism or another condition from this type of immunization?
    
    
12. Should my baby be immunized against rotavirus?
    
    
13. Should my teenage daughter receive the HPV vaccine?