At first, the idea of letting their children receive injections containing bacteria, viruses, or germs that cause serious diseases, such as meningitis and hepatitis B, may seem dangerous to parents. When doctors explain that these injections will actually help protect their children against certain diseases, parents may be even more confused.

Although it seems counterintuitive, vaccines (injections or liquids given orally that contain weakened or dead bacteria, viruses, or germs) actually do help prevent children from getting certain diseases. In the past, there has been some concern about the safety of vaccines, but they are generally very safe and cause few side effects. There are differing opinions about when children should be vaccinated, and there are also a few reasons that children should not be vaccinated against certain diseases. However, the majority of doctors and researchers advocate vaccinating children against many different diseases when they are quite young.

Vaccines: An Overview

Vaccines protect children from diseases because of the way they interact with the body’s immune system. The immune system is the body’s primary defense against invading germs and microorganisms that can cause infection. It is made up of proteins, cells, tissues, and organs that produce substances known as antibodies when a threat is detected. Each antibody is uniquely designed to attack a specific threat to the body, such as a bacteria or a virus.

By introducing weakened or inactive bacteria, viruses, or portions of a germ’s structure into the body, vaccines stimulate the immune system to produce antibodies strong enough to protect the body against these threats. Once the immune system produces antibodies against the bacteria, viruses, or germs in the vaccine, it “remembers” those threats and “knows” how to fight them. Because the immune system is already prepared to fight against those bacteria, viruses, or germs, those threats do not make a child sick if they enter his or her body in the future.

Not only are vaccinations a safe way of preventing diseases, they can also improve the health of large groups of people at a very low cost. In the last half century, vaccines have changed the lives of people around the world by eradicating smallpox and reducing the occurrence of common diseases such as polio, typhoid fever, and measles. Countries without advanced health care systems have also benefited from large-scale vaccination programs because these initiatives require minimal training, equipment, long-term medications, and prolonged medical care.

Some vaccines can cause side effects, such as a low-grade fever and swelling or soreness at the injection site. However, in general, they are very safe. Vaccines are unlikely to cause serious infections because they contain weakened, inactive, or partial bacteria, viruses, or germs. In the U.S., it takes years for vaccines to become available due to the extensive testing they need to undergo. Also, while they are in use, vaccines are continually monitored for their safety and efficacy by a system known as VAERS (Vaccine Adverse Event Reporting System) and external reviewers as well.

One study in particular, published in 1998 in the British medical journal The Lancet, created a scare when it implied a link between the vaccine for measles, mumps, and rubella (MMR) and autism. (Autism is a disease characterized by social impairments and communication difficulties.) However, researchers later discovered that the author of the study committed fraud by altering the data and determined the link between the MMR vaccine and autism was unfounded. Also, several other studies have found no association between autism and MMR or any other vaccine.

When Children Should Receive Vaccinations

The Centers for Disease Control and Prevention (CDC) receive input from the of Pediatrics (AAP) and the of Family Physicians before determining the childhood vaccination schedule that most pediatricians follow. According to this vaccination schedule, children should receive several shots when they are very young (around 26 shots before age 2) and should finish most of their vaccinations by the time they are 6 years old.

The Debate over Childhood Vaccination Schedules

Some doctors and parents disagree with the idea of giving children so many vaccinations when they are so young. Instead, these people advocate a delayed vaccination schedule during which children receive all of the recommended vaccinations but over a longer period of time.

These doctors and parents believe that a delayed vaccination schedule is preferable for several reasons:

• They are concerned that the numerous vaccinations (and the combinations of vaccinations) given to young children can overwhelm children’s immune systems and increase the chance that children will have adverse reactions.

   

• Also, some parents feel that it is unnecessary to risk overwhelming their children’s immune systems at such young ages because most of the other children receive their vaccinations at very young ages. Since the other children are immunized against serious diseases, such as measles, they do not have those diseases. If other children do not have the serious diseases that vaccines are designed to prevent, then some parents feel that their children have a lower risk of getting these diseases.

   

• Finally, some parents still fear a link between vaccinations and autism and do not want to expose their children to that risk at such early ages.

Doctors and parents who advocate giving children many vaccines at young ages have several reasons for disagreeing with the delayed vaccination schedules. These reasons include the following:

• Children are exposed to numerous bacteria, viruses, and germs at very young ages. The delayed vaccination schedules increase the time period when children are susceptible to infection from these threats. Also, younger children are at higher risk for certain diseases, such as the flu, and the risk of complications from infections is highest when children are younger. Thus, protecting children with vaccines as soon as possible decreases their risk of infection as soon as possible.

   

• There are no known benefits of delaying vaccinations. Also, there is no evidence that receiving multiple vaccinations at one time increases children’s risks for adverse reactions.

   

• The vaccines are designed to work with children’s immune systems at the ages when they are recommended. To receive the greatest benefits from vaccinations, it is important for children to receive them when they are recommended.

   

• When children are not immunized early, the chances for outbreaks of diseases, such as polio and measles, increase. For example, cases of measles, mumps, and whooping cough have increased in the recently and have overwhelmingly occurred in children who have not been immunized.

   

• Children who delay immunization may never catch up and may be at an increased risk for infection for their entire lives.

There are some specific instances when doctors recommend against vaccination. For example, children who have certain types of cancer or other diseases that weaken their immune system or those who are taking medications that weaken the immune system should not receive certain vaccines. This is because they may not be able to fight off the weakened forms of the bacteria, viruses, and germs in the vaccines. Thus, they may get sick from the vaccines. Also, if a child has had a severe allergic reaction to the first dose of a vaccine, he or she should not receive another dose of that same vaccine.

If doctors recommend that a child avoid a certain vaccination, parents should ask when and if the child should ever be given that vaccination.

Recommended Childhood Vaccines

The following vaccinations are recommended during childhood:

• Influenza (flu) Vaccine: This vaccine protects against the influenza (or “flu”) virus, which causes a highly contagious infection that attacks a child’s nose, throat, and lungs. Children younger than age 5 are at high risk for flu infection, and children younger than 2 are particularly susceptible. Children with chronic (long-lasting) health conditions, such as cancer and diabetes, are also susceptible to flu infections.

The vaccine is available in a shot (which contains dead viruses) and also in a nasal spray (which contains live but weakened viruses). Children should receive the flu vaccine every year at the beginning of the flu season (usually in October or November) starting when they are six months old. Children under age 2 should not receive the nasal spray form of the vaccine, though, because the nasal spray is more likely to cause adverse reactions as it contains the live virus. The viruses that cause the flu change from year to year, so receiving the vaccination yearly is important.

Children who are severely allergic to eggs and egg products should not receive flu shots because the ingredients for the vaccine are grown inside eggs. Children who have had Guillain-Barré syndrome (a rare disease of the nervous system which causes progressive weakness) should also not receive this vaccination.

• DTaP Vaccine. The DTaP vaccine is actually a group three vaccines combined together into one shot. It protects against diphtheria, tetanus, and pertussis.
   
  • Diphtheria is a disease that can attack a child’s throat, block the airway, and cause difficulty breathing. Sometimes, it also attacks the heart, which can cause heart failure and death. 
     
  • Tetanus, also called “lockjaw” occurs when a certain type of bacteria contaminates a wound. Tetanus affects the nerves, leading to severe muscle spasms and even death.
     
  • Pertussis, also called whooping cough, is a respiratory disease that progresses to severe coughing, making it difficult to breathe, eat, and drink. Pertussis can cause severe complications, such as pneumonia, convulsions, brain damage, and even death. Children under a year old are vulnerable to serious complications of pertussis, and babies under six months are especially at risk.
     

The DTaP vaccination is given as a series of five shots when children are 2 months old, 4 months old, 6 months old, between 15 and 18 months old, and between 4 and 6 years old. If children have uncontrolled seizures or neurological diseases, the pertussis component of the vaccine may not be given. Instead, the child will receive a DT (diphtheria and tetanus) vaccine.

When children are around 11 years old, they should have a vaccine called Tdap, which is a booster shot for DTaP. A booster shot is an additional dose of vaccine that is designed to continue to protect a child from infection. Then, doctors recommend Td (tetanus and diphtheria) booster shots every 10 years.

• IPV Vaccine. The inactivated poliovirus vaccine (IPV) protects against polio. Polio is a disease that can result in permanent paralysis in the arms, legs, or muscles that one uses to breathe and swallow, which can cause death. It is given four times as a shot at ages 2 months, 4 months, 6 to 18 months, and 4 to 6 years. Until 2000, polio vaccinations were given orally (the oral poliovirus vaccine or OPV). The change to the IPV vaccine was made because there was a small risk of developing polio after receiving the OPV vaccine, as the OPV vaccine contained a weakened, live polio virus.

   

• MMR Vaccine. This vaccine protects against measles, mumps, and rubella.
   
  • Measles causes symptoms including a rash, cough, and fever. It can also lead to ear infections, pneumonia, swelling in the brain, and even death.
    
  • Mumps causes fever, headache, and painful swelling of the major saliva glands. It can lead to meningitis (an infection of the membranes that cover the brain and spinal cord), and in rare cases to swelling of the brain.
     
  • Rubella is also called the German measles and causes a fever, rash, and swelling of the glands in the neck. It can also cause swelling in the brain or bleeding problems.
     

The MMR vaccine is given as a series of two shots – one when a child is 12 to 15 months old and the second when a child is between 4 and 6 years old.

• Hib Vaccine. The Hib vaccine protects against the Haemophilus influenzae type b bacteria, which can cause meningitis, pneumonia, and a severe throat infection that may cause choking. Typically, children receive the vaccine as a series of four shots - one at 2 months old, one at 4 months old, one at 6 months old, and a booster dose when they are between 12 and 15 months old.

   

• Varicella vaccine. The varicella vaccine helps prevent chickenpox (a common, contagious, viral childhood disease that causes blister-like red spots to appear all over the body). Children receive this vaccine as a series of two shots – one when they are between 12 and 15 months old and a booster shot when they are between 4 and 6 years old.

Older children can also receive the varicella vaccine if they have not already. Children under age 13 may receive two doses of the vaccine given at least three months apart. Children 13 years old or older can receive two doses of the vaccine at least one month apart.

• Hepatitis B Vaccine (HBV). The HBV vaccine protects against the hepatitis B virus, which is an infection of the liver that can cause cancer of the liver and even death. The vaccine is given as a series of three shots. Children receive the first shot shortly after they are born. If the mother of a child has the hepatitis B virus, her baby needs to receive the HBV vaccination within 12 hours of birth along with another shot called HBIG to be immediately protected. Children receive the second HBV shot when they are between 1 month and 2 months old, and they receive the third HBV shot when they are between 6 and 18 months old. A dose of the HBV vaccine can be combined with a dose of the Hib vaccine, so that children receive one dose of each vaccination in a single shot.

   

• Pneumococcal Conjugate Vaccine (PCV). This vaccine protects against a type of bacteria (called pneumococcus) that causes ear infections and more serious illnesses, such as bacterial meningitis and bacteremia (an infection in the blood stream). Children under 2 years old and children with certain medical problems, such as HIV and AIDS, sickle cell anemia, and chronic heart or lung conditions, are especially susceptible to infections caused by pneumococcus bacteria.

The PCV vaccine is given as a series of four shots when children are 2 months old, 4 months old, 6 months old, and between 12 and 15 months old. In addition, doctors recommend that children who are between 2 and 5 years old and at high risk for infections caused by pneumococcus bacteria because of their medical conditions receive another dose of the PCV vaccination.

• Meningococcal Conjugate Vaccine (MCV4). This vaccine protects against four different types of bacterial meningitis, which is an infection of the membranes that cover the brain and spinal cord. Bacterial meningitis can cause high fever, headache, stiff neck, and confusion. The disease can also cause more serious complications, including brain damage, hearing loss, and blindness. Although bacterial meningitis is rare, it is highly contagious.

Children between 11 and 12 years old should receive the MCV4 vaccine. If children do not receive the vaccine when they are between 11 and 12, they should receive it before they start high school. If older teens still have not been vaccinated, they should receive the MCV4 vaccine if they are entering college or the military and will be living in a dormitory setting.

Parents should talk to their children’s doctors about delaying or avoiding immunization with the MCV4 vaccine if their children have had allergic reactions to the DTaP vaccine, allergic reactions to latex, or a history of Guillain-Barré syndrome (a disease of the nervous system which causes progressive weakness).

• Rotavirus Vaccine. Rotavirus is a common virus that can lead to dehydration, as it causes severe vomiting and diarrhea. Infants and children are particularly high at risk for rotavirus infection. This vaccine is a liquid that is swallowed. Children receive this vaccination when they are 2 months old and 4 months old. Children can also receive the rotavirus vaccine for a third time when they are 6 months old if doctors use certain brands of the vaccine.

   

• Hepatitis A Vaccine (HAV). This vaccine protects against the hepatitis A virus, which causes inflammation of the liver that can lead to fever, nausea, vomiting, and jaundice (yellow skin). Children receive the HAV vaccine in two doses – one when they are between 12 and 23 months old and the second six months after they receive the first dose.

Summary

Children receive vaccines in order to be protected from serious diseases, including measles, hepatitis B, and meningitis. Vaccines contain weakened or dead versions of the bacteria, viruses, or germs that cause these diseases. The immune system is able to “remember” how to fight against bacteria, viruses, and germs that it has already encountered. Thus, once the immune system handles the weakened or dead forms of bacteria, viruses, or germs in vaccines, it is prepared to fight against the full strength versions of these threats.

Researchers have questioned the safety of vaccines, and at one point in time, the MMR vaccine was thought to be associated with autism. However, it was discovered that this association was unfounded. Most doctors agree that vaccines are generally very safe and cause few side effects.

There are different perspectives on when children should be vaccinated. Some people believe in a delayed immunization schedule where vaccines are spread out over a longer period of time. On the other hand, most doctors stress the importance of vaccinating children against several different diseases as early as possible so that they have a lower chance of becoming infected with a serious illness, such as polio or the measles. Vaccinations have led to fewer cases of these serious illnesses, so parents should talk to their children’s doctors if they are thinking that their children should not be immunized for any reason.