Measles; Rubella; Tetanus; Vaccinations; Whooping cough
Immunizations against childhood diseases save millions of lives. American vaccination rates are now at an all-time high. Disease and death from diphtheria, pertussis, tetanus, measles, mumps, rubella, and Haemophilus influenzae (H. influenzae) type b are at or near record lows. In adults, immunizations against influenza (the flu), pneumococcal pneumonia, hepatitis, and other ailments have likewise saved many lives and prevented many cases of serious illness. A new vaccine has been shown to be highly effective for preventing the virus that leads to cervical cancer.
More than 70 bacteria, viruses, parasites, and other infectious microbes cause major human disease. Fortunately, vaccines are either available or being developed against a portion of them. With the advent of new or newly feared biological threats, emerging infections, and bacterial resistance to common antibiotics, immunizations are assuming an increasingly important role in maintaining the health of billions of people worldwide.
Most vaccines are given by an injection, but some can be taken orally (by mouth) or by a nasal spray. They usually contain one of four components that cause an immune response:
The harmless infectious component in the vaccine teaches the immune system to recognize the full-strength, live, and harmful substance or organism. The immune system than knows to attack it real exposure occurs. The antibodies produced in response to the vaccine remain in the body, preventing future illness from such an exposure. This is called immunity.
Combination Vaccines. The American Academy of Pediatrics and American Academy of Family Physicians recommend that health care providers use, whenever possible, combination vaccines instead of individual components. Combination vaccines for diphtheria, tetanus, and pertussis (DTaP), and for measles, mumps, and rubella (MMR), have been available for years. New combinations that cover up to 5 vaccinations are being developed and are proving to be safe and well tolerated in infants as young as 2 months. For example, one that combines DTaP, hepatitis B, and the polio vaccine (Pediarix) has been approved in 2002. It is as effective as the individual vaccines when given to children ages 6 weeks to 6 years.
There is some concern that increasing use of combinations may reduce the potency of some of the vaccines. Some parents are also worried about increased side effects. Studies to date, however, are reporting that combinations are effective and safe.
Passive Immunity. Another form of protection against disease is called passive immunity. This approach uses immune globulin, which are blood products containing antibodies. Immune globulin is generally used for people who cannot be vaccinated, when immediate protection is required, or to prevent severe complications of the disease. In some circumstances, passive immunity can interfere with active vaccinations, particularly live-virus vaccines. Therefore, if possible, these two immunization types should not be administered within weeks or even months of each other.
General Information on Side Effects. Vaccines can have side effects, which are nearly always mild, such as swelling at the injection site or fever. There have been a number of reports in the popular press about alarming side effects in many vaccines. Anti-vaccine groups vocally oppose immunizations in children. Although it is true that no vaccine is 100% safe, childhood infections have not been wiped out. Without immunization, parents risk exposing their children to diseases that in the past have killed millions of young children.
Routine Childhood Vaccines. Experts recommend that all children be routinely vaccinated against the following diseases:
Many vaccinations are first given during infancy. Even premature infants can, in most cases, be given vaccinations on a normal schedule. Note: These facts pertain to children in the United States. Children from other countries have not been well studied. Parents who adopt internationally may want to have their children's immunity assessed by a physician. Some evidence suggests that their medical records may not correctly reflect immunization status and that many adopted children, such as those from China, have not had many important vaccinations.
Common Adolescent and Adult Vaccines. Vaccinations against the following disorders are also recommended routinely for certain adults More information on these vaccines is discussed in the Specific Vaccinations section:
Thimerosal is a preservative that has been used in many vaccines since the 1930s. (Preservatives are necessary to prevent vaccine contamination with live organism in vials that are used for vaccinating multiple people.) Thimerosal contains nearly 50% mercury by weight, but the amount of mercury thimerosal introduced into vaccines has been very small (approximately 25 micrograms of mercury per 0.5 mL dose, according to the Food and Drug Administration). Some people are concerned about possible neurologic consequences from cumulative doses of mercury contained in vaccines given to infants.
In 2004, the Institute of Medicine (IOM) Safety Review Committee reported the results of studies in the U.S. and several European countries evaluating a possible association between thimerosal and autism. They concluded that scientific studies did not find that thimerosal caused autism.
Currently,, all vaccines recommended for children aged 6 or younger contain either no thimerosal or only trace amounts of it, with the exception of the inactivated influenza vaccine. (A limited supply of this vaccine, containing only trace amounts of thimerosal, is available for use in infants, children, and pregnant women.) A trace amount means that a given dose of vaccine contains less than 1 part per million.
Inactivated-virus and toxoid vaccines are usually safe in pregnant women, although any vaccination should be delayed, if possible, until the second or third trimester. Because of a possible risk to the fetus, live-virus vaccines should not be given to pregnant women or those likely to become pregnant within 28 days unless such women need immediate protection against life-threatening diseases, such as yellow fever, that are only prevented using live-virus vaccines. The live-virus MMR combination, which vaccinates against measles, mumps, and rubella, is not given to pregnant women because of the theoretical risk of the live-rubella vaccine to the fetus.
In general, vaccines are not completely effective for patients whose immune systems are compromised by disease or medications. Often, such patients are given immune globulin if they are exposed to infection. It may take 3 months to 1 year before a person who has stopped taking immunosuppressant drugs regains the full ability to be successfully immunized against disease.
Live-virus vaccines are not usually given to people whose immune system has been compromised by illness or by the use of medications.
People who should not get live-virus vaccinations include:
|Childhood Immunization Schedule**|
Chickenpox (Varicella Zoster)
Diphtheria, Tetanus, Pertussis (DTaP)*
Haemophilus influenzae type (Hib)
Hib (Depending on brand. For example, no third dose is required for PedvaxHIB or ComVax.)
|Rotavirus (not needed if Rotarix was administered at 2 and 4 months)|
12 to 15 months
DTaP* (Typically between 15 and 18 months. May be given as early as 12 months in high-risk children as long as 6 months have passed since the third dose.)
Hib (Sometime between 12 and 15 months.)
|HepA (In 2 does, between 12 and 23 months)|
2 years old
In children who have not been fully vaccinated.
4 to 6 years
11 to 12 years
Varies. (If previously missed, two doses should be given at least four weeks apart.)
In adolescents through age 18 in selected areas.
Hepatitis B (Hep-B)*
Measles, Mumps, Rubella (MMR)
Pneumococcal Vaccine (PCV)
Polio (Inactive virus) (IPV)*
Human Papillomavirus (HPV)
Hep-B before discharge from hospital. (Within 12 hours and with Hep B immunoglobulins when mothers are infected.) *
Hep-B some time between 1 and 2 months depending on risk. *
Hep-B some time between 6 and 18 months. *
IPV* (Advised at some point between 6 and 18 months.) *
12 to 15 months
MMR (Some time between 12 and 15 months.)
2 years old
PCV -- 1 dose for children not previously vaccinated.
4 to 6 years
PCV -- 1 dose in high-risk children up to age 59 months.
11 to 12 years
Hep-B (If vaccinations were previously missed). Two or 3 doses a few months apart.
MMR (If vaccinations were previously missed).
|HPV -- 3 doses (Females)||Meningitis -- MCV4 ***|
* A one-shot combination vaccine (Pediarix) has been approved that covers polio, hepatitis B, diphtheria, pertussis, and tetanus (DTaP) and should simplify the immunization process. It would be given as a single injection at 2, 4, and 6 months with booster shots given at 12 to 15 months and 4 to 6 years.
**All children aged 6 months - 18 years should receive an annual flu shot. Children younger than 9 years of age, who are receiving this vaccine for the first time (or who were vaccinated for the first time during the previous season with only 1 dose) should receive 2 doses of the flu vaccine at least 4 weeks apart.
*** Two types of meningococcal vaccine are available. Children and adults under age 55 should receive the MCV4 vaccine. The U.S. Advisory Committee on Immunization Practices (ACIP) recommendations now call for routine vaccination of all adolescents (aged 11 - 18) at the earliest opportunity, ideally at age 11-12. The ACIP also recommends vaccination for those previously defined as being at increased risk, including people exposed to single cases or outbreaks; freshmen college students living in dorms; military recruits; travelers to developing countries where outbreaks have occurred; and patients with problems in the spleen.
Of great concern are anti-immunization organizations and web sites, which were formed mostly because of unsubstantiated reports linking small numbers of serious problems to some vaccines. The following watchdog systems are now in effect to monitor side effects from vaccination:
Studies using these systems are ongoing and none to date have confirmed reports of any significant association between most vaccines and severe side effects that would outweigh the benefits of these important and lifesaving agents.
No vaccine is 100% safe. Allergic and serious reactions are possible. In 2 cases, the early polio vaccine and the first rotavirus vaccine, problems did occur, and some were serious. It is important to note, however, that even in these cases, the vaccines were withdrawn and the severe events were still far fewer than the number of lives saved. Both of these vaccines have been changed and are now safe.
The focus on vaccination side effects is ironic due to the fact that reports of such adverse effects outnumber actual infections. In general, those who do not receive vaccinations are at a higher risk for infection from the illness the vaccine protects from. Because vaccinations have been in existence for so long, today's parents have no direct knowledge of the consequences of these dreaded infections, which killed or severely sickened millions of children in the past.
Infants often accept the first injection easily, since they are not expecting it. It gets more difficult, however, with each additional injection. Simply providing love and warmth can help children of all ages tolerate immunizations.
American Academy of Pediatrics Committee on Infectious Diseases. Prevention and control of meningococcal disease: recommendations for use of meningococcal vaccines in pediatric patients. Pediatrics. 2005 Aug;116(2):496-505.
Centers for Disease Control and Prevention. Recommended Immunization Schedule for Ages 0 - 6 Years, United States, 2009.
Centers for Disease Control and Prevention. Recommended Immunization Schedule for Ages 7 - 18 Years, United States, 2009.
Centers for Disease Control and Prevention. Recommended Immunization Schedule for Adults, United States, 2009. Available online.
Centers for Disease Control and Prevention. Revised Recommendations of the Advisory Committee on Immunization Practices to Vaccinate All Persons Aged 11 - 18 Years with Meningococcal Conjugate Vaccine. Morbidity and Mortality Weekly Report. 2007:56(31);794-795.
Centers for Disease Control and Prevention. Notice to Readers: Recommendation from the Advisory Committee on Immunization Practices (ACIP) for Use of Quadrivalent Meningococcal Conjugate Vaccine (MCV4) in Children Aged 2 - 10 Years at Increased Risk for Invasive Meningococcal Disease. Morbidity and Mortality Weekly Report. 2007;56(48);1265-1266.
Centers for Disease Control and Prevention. Prevention of influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2008. Morbidity and Mortality Weekly Report. 2008:57(No. RR-7).
Centers for Disease Control and Prevention. Update on Hib Vaccine Shortage. October 22, 2008. Available online.
Chaves SS, Gargiullo P, Zhang JX, Civen R, Guris D, Mascola L. Loss of vaccine-induced immunity to varicella over time. NEJM. March 15, 2007;356:1121-1129.
Garland SM, Hernandez-Avila M, Wheeler CM, Perez G, Harper DM, Leodolter S, et al. Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases. NEJM. May 10, 2007;356:1928-1943.
GlaxoSmithKline. Boostrix Prescribing Information. December, 2008.
Grijalva CG, Nuorti JP, Arbogast PG, Martin SW, Edwards KM, Griffin MR. Decline in pneumonia admissions after routine childhood immunisation with pneumococcal conjugate vaccine in the USA: a time-series analysis. Lancet. April 7, 2007;369:1179-1186.
Poehling KA, Szilagyi PG, Crijalva CG, Martin SW, LaFleur B, Mitchel E, et al. Reduction of frequent otitis media and pressure-equalizing tube insertions in children after introduction of pneumococcal conjugate vaccine. Pediatrics. April 4, 2007;119:707-715.
US Food and Drug Administration. FDA Approves Expanded Uses for Gardasil to Include Preventing Certain Vulvar and Vaginal Cancers. September 12, 2008.
US Food and Drug Administration. FDA Approves New Vaccine to Prevent Gastroenteritis Caused by Rotavirus. April 3, 2008.
US Food and Drug Administration. Zostavax Questions and Answers. Available online. Last Accessed 3/12/2009.
World Health Organization. Immunization surveillance, assessment and monitoring -- United States of America (the) reported cases. Last Updated: December 18, 2008. Available online.
Zuckerman JN. Protective efficacy, immunotherapeutic potential, and safety of hepatitis B vaccines. J Med Virol. 2006 Feb;78(2):169-77.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885