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Frequently Asked Questions About Vaccine Reactions

Vaccine Reactions

Q: Have specific reactions been associated with specific vaccines?

A: Like any medical product, every vaccine carries risks that can be greater for some than others. Some vaccines have side effects and symptoms which occur more often in one vaccine than other vaccines. As a consumer vaccine safety advocacy organization, NVIC worked on the National Childhood Vaccine Injury Act of 1986 and was responsible for urging the creation of safety provisions in that historic law. This included a centralized vaccine reaction reporting system, the Vaccine Adverse Event Reporting System (VAERS), that is jointly operated by the federal Food and Drug Administration and Centers for Disease Control.

If your, or your child, experiences serious health problems following vaccination, regressed physically, mentally or emotionally after vaccination or has experienced acute symptoms within hours, days or weeks of vaccination it should be reported to the federal Vaccine Adverse Event Reporting System (VAERS) website, or by calling 1-800-822-7967. Your doctor is required by law to report adverse reactions to vaccination within 30 days of vaccination. You, a nurse or health department official may also report serious health problems following vaccination to VAERS.

NVIC also provides as a public service our Ask Eight, Before You Vaccinate webpage that gives and overview of reaction symptoms and injury compensation. Below are some examples of reaction symptoms. If you observe any of these symptoms – or any other symptom that causes you concern – get medical help right away.:

  • Rash, hives or severe itching
  • Swelling, redness and pain at the injection site
  • High fever over 103F
  • Difficulty breathing or wheezing
  • Rapid heart beat or chest pain
  • Dizziness or sudden collapse/fainting
  • Paleness or changes in skin or lip color
  • Muscle weakness or limpness
  • Excessive sleepiness or lack of responsiveness
  • Loss of vision or speech
  • Nausea and vomiting
  • Severe diarrhea
  • Unusual irritability or other behavior changes
  • Prolonged crying (especially high-pitched screaming in infants)
  • Seizures or convulsions (shaking, twitching, jerking)
  • Joint and body pain
  • Head pain
  • Excessive bruising under the skin
  • Numbness or tingling in hands, arms, feet
  • Paralysis

Although it has been the law since 1986 for doctors and other vaccine providers to report hospitalizations, injuries, deaths and serious health problems following vaccination to VAERS, it is estimated that less than 10 percent, perhaps less than one percent of all vaccine-related health problems are ever reported to VAERS. It is very important that ALL serious health problems, which develop after vaccination, be reported to the federal health authorities at VAERS. NVIC has acted as a watchdog on VAERS and we encourge consumers to also report vaccine reactions to NVIC's Vaccine Reaction Registry, operated since 1982. We also host MedAlerts, the service that allows the public to easily search the federal VAERS database.

As a society we need to know how many people who get vaccinated are getting sick after vaccination and how many go on to die or are permanently injured. In addition, information provided to the VAERS may also help identify common factors, which affect certain individuals who have adverse responses to vaccination. More information can lead to safer vaccines, safer vaccine policies and medical research to develop screening techniques to help reduce vaccine reactions.

Q: I'm trying to get a list that identifies the adverse reaction rates of all the childhood vaccines. In other words, which vaccines have the highest rate of adverse reactions?

A:  Although this information should be available, it either does not exist or is not available to the public. Theoretically, it should be possible to calculate for each vaccine how many adverse reactions are reported to the federal reporting system, VAERS, every year. However, we know that only between one and ten percent of reactions are ever reported even though there has been a federal law in place since 1986 that requires serious health problems following vaccination to be reported to the government.

Even if all the vaccine-related adverse health events were reported, it wouldn't necessarily mean that every adverse health event that has been reported to VAERS after vaccination has been solely caused by the vaccine(s) recently given. Another complicating factor is that, today, children tend to get many different vaccines simultaneously at every office visit. As a result, it is often difficult to attach a specific health problem following vaccination to a specific vaccine.

Another major limitation to evaluating "adverse reaction rates" is that "rates" can be computed by dividing the numerator (number of adverse reactions) by the denominator (number of vaccines given). There isn't a valid publicly available source of data regarding the numbers of doses of each vaccine and numbers of children who receive doses of each vaccine annually in the U.S.

Other than the VAERS database, information on adverse reaction rates must come from large, prospective studies that are conducted over a long period of time to evaluate the health outcomes of children who receive multiple vaccines from birth. An ideal clinical trial would compare the health of those children who receive many vaccines to those who received far fewer and no vaccines. No such clinical trial has ever been conducted.

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