Preventing Disease with Vaccination

Vaccination Is Very Important to Health
The development of vaccination to prevent infectious disease is among the most important medical and public health advances that prevent illness, suffering, long-term disability and death.  Infections are the most common cause of human disease and prior to the advent of vaccination, sanitation and antibiotics, they were also the commonest cause of death.  Good hygiene and sanitation have helped help prevent the spread of disease, but the germs that cause disease are still with us, and without vaccination they would make many people sick.

The Centers for Disease Control and Prevention (CDC) recommends vaccinations to protect children against 16 infectious diseases, including measles, mumps, rubella (German measles), varicella (chickenpox), hepatitis B, diphtheria, tetanus, pertussis (whooping cough), Haemophilus influenza type B (Hib), polio, influenza (flu), and pneumococcal disease.

How Vaccination Works
When a disease-causing microbe (virus, bacteria, or a parasite like malaria) gets into your body, your immune system recognizes the invader and mobilizes to destroy it.  Often this response works well but it can be too slow and weak to prevent illness. Vaccines help the body’s immune system prepare for and respond more quickly and strongly to future attacks. Vaccines consist of killed or modified microbes, parts of microbes, or microbial DNA that make the body mobilize the immune system as though an infection occurred. 

A vaccinated person’s immune system attacks the harmless vaccine and prepares for invasions against the kind of microbe the vaccine contained.  If re-exposure to the infectious microbe occurs, the immune system will quickly and strongly respond to stop the infection.  Vaccines are very effective, most childhood vaccines produce immunity about 90 - 100% of the time.

There is another way that vaccines can prevent outbreaks of disease and save lives. When a high proportion of a community is immunized against a contagious disease, even those members of the community who are not vaccinated get some protection against that disease because there is little opportunity for an outbreak. This helps those who are not eligible for certain vaccines—such as infants, pregnant women, or people with a weak (immunocompromised) immune system. This phenomenon is known as community or herd immunity.  If many people opt out of vaccination, not only are they at risk of illness, but the benefits of herd immunity are also lost.

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Who Should Be Vaccinated?         
Because of low levels of vaccine-preventable diseases in the United States, and unrealistic fears about the risks of vaccination, some people are reluctant to get vaccinated or have their children vaccinated.  It should be kept in mind that many of the viruses and bacteria that cause illness still circulate in this country.  Recent outbreaks of pertussus (whooping cough) among children who were not vaccinated are a vivid example of why it’s important that children, especially infants and young children, but also teenagers and adults, receive recommended immunizations on time. 

How Safe Are Vaccines?
Vaccines are not free from side effects, or “adverse effects,” but most are very rare or very mild--for example, a sore arm or low-grade fever--and go away within a few days. Very rarely, people experience more serious side effects, like allergic reactions.

Studies have shown a small increased risk for febrile seizures during the first to second week after the first vaccination with measles, mumps, rubella (MMR) vaccine and the first dose of measles, mumps, rubella, and varicella (MMRV) vaccine.  Studies have not shown an increased risk for febrile seizures after the acellular pertussis vaccine, DTaP, or after varicella (chickenpox) vaccine.

It should be kept in mind that febrile seizures can happen with any condition that causes a fever. Febrile seizures are usually brief, lasting one or two minutes, and they do not cause any permanent neurological damage.  Up to 5% of young children will have at least one febrile seizure, usually associated with getting sick.  Causes include common childhood illnesses like colds, the flu, an ear infection, or roseola. 

Although vaccines sometimes cause fevers, febrile seizures after vaccination are rare. Getting a child vaccinated as soon as recommended prevents febrile seizures by protecting young children against measles, mumps, rubella, chickenpox, influenza, pneumococcal infections and other diseases that can cause fever and febrile seizures.

It is important to keep in mind that some adverse health problems following a vaccine may be due to coincidence and are not caused by the vaccine.  A few years ago flawed research claimed that autism was caused by vaccination.  Although this link has been disproved, some people still believe it and refuse vaccination for their children and leave them at risk of serious illness and even death.

The Food and Drug Admin­istration, requires that vaccines be tested for safety before they enter the market, and their performance is continually evaluated to identify any risks that might appear over time. 
Under the National Childhood Vaccine Injury Act of 1986, Congress established the National Vac­cine Injury Compensation Program (VICP) to provide compensation to peo­ple injured by vaccines. Anyone who thinks they or a family member—often a child—has been injured can file a claim.

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If Someone Has a Reaction to a Vaccine
If someone has a reaction to a vaccine, follow these steps:

  1. Call a doctor. If the reaction is severe, take the person to a doctor immediately.
  2. Tell your doctor what happened, when it happened, and when the vaccination was given.
  3. Ask your doctor, nurse, or health department to file a VAERS form, or call VAERS yourself at 1-800-822-7967.

More information on safety can be found at :

Who Should Not Get Vaccinated?
Some people should not get certain vaccines or should wait to get them. For instance, children with compromised immune systems, as occurs with some cancer treatments, often need to wait to be vaccinated. Be sure to tell your health care provider if you have health problems or known allergies to medications or food.  If a person has had a severe allergic reaction to a vaccine, a following dose is not recommended. However, a person with a mild, common illness, such as a cold with a low-grade fever, does not have to wait to be vaccinated. For more information, visit Who Should Not be Vaccinated with These Vaccines?

Which Different Diseases Can Be Prevented with Vaccination?
Some vaccines are recommended only for travelers to places where the diseases occur.  There are other vaccines, such as against anthrax, that are usually reserved for high-risk groups of people such as those in the military. Smallpox has been eliminated globally and vaccination against smallpox is no longer needed.
Listed below are vaccines licensed in the United States.  Side effects that have been associated with each of them can be found at:
http://www.cdc.gov/vaccines/vac-gen/side-effects.htm. (The information at this website is copied directly from CDC's Vaccine Information Statements, which in turn are derived from the Advisory Committee on Immunization Practices (ACIP) recommendations for each vaccine).

  1. Adenovirus
  2. Anthrax
  3. DTaP (Diphtheria, Tetanus, and acellular Pertussis)
  4. Hepatitis A
  5. Hepatitis B
  6. Hib (Haemophilus influenzae type b)
  7. HPV (Cervarix) (Human Papillomavirus)
  8. HPV (Gardasil) (Human Papillomavirus)
  9. Influenza
  10. JE-Ixiaro (Japanese Encephalitis)
  11. MMR (Measles, Mumps, and Rubella)
  12. MMRV (Measles, Mumps, Rubella, and Varicella)
  13. Meningococcal
  14. PCV13 (Pneumococcal Conjugate Vaccine)
  15. PPV23 (Pneumococcal Polysaccharide)
  16. Polio
  17. Rabies
  18. Rotavirus
  19. Shingles
  20. Smallpox
  21. Td (Adult Tetanus & Diphtheria)
  22. Tdap (Combined Tetanus, Diphtheria & Pertussis)
  23. Typhoid Fever
  24. Varicella (Chickenpox)
  25. Yellow Fever

The preceding essay was adapted from information published by the Centers for Disease Control and Prevention on Vaccines and Immunizations found at: http://www.cdc.gov/vaccines/default.htm

Vaccination schedules for infants and children up to age 18 can be found at:

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