U.S. flag An official website of the United States government
  1. Home
  2. Vaccines, Blood & Biologics
  3. Safety & Availability (Biologics)
  4. Vaccine Safety Questions and Answers
  1. Safety & Availability (Biologics)

Vaccine Safety Questions and Answers

Under the National Childhood Vaccine Injury Act (NCVIA), are health care providers and vaccine manufacturers required to report adverse events following the administration of vaccines?

Health Care Providers

Health care providers are subject to the adverse event reporting provisions of the NCVIA. This act mandates the reporting of the following events:

  • Any event set forth in the Reportable Events Table that occurs within the time period specified.
  • Any event listed in the manufacturer's package insert as a contraindication to subsequent doses of the vaccine.

There are no penalties specified in the law for health care providers who do not report adverse events. However, FDA takes active steps to educate physicians, nurses and other health care workers about the importance of reporting adverse vaccine events.


Vaccine Manufacturers

Under FDA regulations [21 CFR, Subpart D - Reporting of Adverse Experiences, Section 600.80] and the Vaccine Adverse Event Reporting System (VAERS), licensed vaccine manufacturers must report to FDA adverse experience information. FDA has a number of enforcement options at its disposal that can be used if a vaccine manufacturer fails to establish and maintain records, and report adverse events under VAERS.

If a manufacturer were to fail to report an adverse event, FDA would warn the firm that it is out of compliance with the law. FDA also would examine the firm's total compliance situation and take further action according to the severity of the reporting violation. If necessary, FDA has the authority to revoke a manufacturer's biological product license for a vaccine.


Why is the definition of "event" defined as any "adverse event?"

The agency does not have a formal definition of "event". An "event" is simply an outcome. Any outcome that an individual, whether a health care provider or consumer, believes may have resulted from an administration of a vaccine, may be reported to VAERS. Any such report will be entered into the system, whether or not there appears to be a causal relation to the vaccine. Thus, there can be no precise definition of "event," since the reporters are the ones who determine what is reported.


I have heard a number of conflicting reports regarding increased safety concerns about vaccine inoculation. In light of the recent safety reports, why should my child be vaccinated?

Due to the success of immunization programs, the incidence of vaccine-preventable infectious diseases has declined. Therefore, individuals are less aware of the serious consequences of vaccine preventable illnesses. While vaccines are extremely safe and effective, no medical product is 100 percent safe or effective. Vaccines have been proven, over decades, to be one of the safest and most powerful disease prevention tools available.

Today there are far fewer visible reminders of the suffering, injuries, and premature deaths caused by diseases that can now be prevented with vaccines. For most of the vaccine-preventable diseases, there has been a 95 percent or more reduction in incidence. Routine immunization has eradicated smallpox from the globe and eliminated wild polio virus in this country. Vaccines have reduced preventable infectious diseases to an all-time low and few children suffer the devastating effects of these illnesses.

Prior to approval by FDA, vaccines are extensively tested by scientists to ensure that they are effective and safe. FDA has a stringent regulatory process for licensing vaccines that serves as a model for other countries.

For reasons related to the individual, not all vaccinated persons develop immunity. Most routine childhood vaccines are effective for 85% to 95% of recipients. Differences in the way individual immune systems react to a vaccine account for rare occasions when people are not protected following immunization or when they experience side effects. Vaccines are licensed, after stringent testing and study, because the benefits offered to the individual far outweigh the risk of serious health effects. In fact, some risks for serious health effects following vaccination are so rare that they currently cannot be measured.

Immunization programs optimally prevent the threat of dangerous infectious diseases that threaten the lives of our citizens, especially the Nation's children and elderly. Vaccines are among the 20th century's most successful and cost-effective public health tools for preventing disease, disability, and death.


What does CDC do when someone wants to exempt out of vaccinations?

Enacting and enforcing immunization laws and regulations are the responsibility of State governments. CDC supports States' decisions to require certain immunizations as recommended on the Childhood Immunization Schedule for children entering school and childcare facilities. Almost all State immunization mandates pertain to entrance into school and childcare facilities. Many States also have college immunization requirements. States' approaches to exemptions for immunization requirements vary. All States allow medical exemptions for immunization. Forty-eight States permit exemptions for religious reasons and 15 States permit parents to claim exemptions on philosophical grounds. Implementation of religious and philosophical exemptions also varies among States. In some States, immunization program staff review written applications for exemption before granting or denying religious or philosophical exemptions. In other States, parents can obtain exemptions by simply signing a form which is accepted without review.

State public health laws and regulations are enacted pursuant to the provisions of individual State constitutions. CDC guidelines are voluntary rather than regulatory. CDC works with States that are ultimately responsible for the development and enforcement of school laws. The issue of philosophical exemptions in State laws was reviewed by the National Vaccine Advisory Committee (NVAC), which is made up of experts in immunization policy. The Committee supports the current policy, which gives States flexibility in developing and enforcing immunization laws. This issue, as well as other immunization issues, are periodically assessed by the NVAC.


Why don't we give parents a choice in deciding if they want to vaccinate their children?

Protecting a child through immunization is a parent's decision, taken in discussion with their doctor. The Federal Government may recommend that States develop laws or requirements for vaccines, but whether the State includes a given vaccine in its regulations and how informed consent is to be obtained are State decisions. Currently, 48 States allow religious exemptions to vaccination and 15 allow philosophical exemptions, in addition to the medical contraindications that are the same in all 50 States. The rationale for limiting choice is that vaccinations have been a very effective approach to protecting the public's health in the United States. The first article in a series on ten great achievements in public health in the 20th century highlighted the impact of vaccines universally recommended for children (Morbidity and Mortality Weekly Report; CDC 1999;48:243-48).

Because of high vaccine coverage rates today, one may focus on rare, potentially vaccine-associated adverse effects, but before vaccines were introduced there were over 175,000 cases of diphtheria annually (1920-22), over 147,000 cases of Pertussis (1922-25), and over 503,000 cases of measles (1951-54). More recently, an estimated 20,000 cases of invasive infections such as meningitis caused by Haemophilus influenzae type b occurred in 1985. Now, because of vaccination, the number of cases of these infections has been decreased by about 96% to 100%. But lessons from other countries have relevance for the United States - 1) if vaccination rates decrease, the number of cases of infection will increase as occurred in the United Kingdom and Japan after concerns about adverse events associated with the whole cell Pertussis vaccine resulted in decreased immunization (In the U.S. today, less reactogenic acellular Pertussis vaccines are now recommended); and 2) the decrease in disease of 96% to 100% exceeds the level of vaccine coverage. This is because at high vaccination rates, the circulation of a bacteria or virus may be decreased which lessens the chance that even someone who has not been immunized will get disease. This "herd immunity" is important because some persons can not be vaccinated because of illnesses such as cancer and high vaccination rates in the community will protect them from disease.


In addition to the data available on the approved product labeling, how do I obtain adverse event information regarding the vaccine my child received?

This information can be obtained by filing a Freedom of Information Act (FOIA) request with FDA. If you would like adverse event information on a specific lot of vaccine, please call 1-800-835-4709 or send an e-mail to ocod@fda.hhs.gov.


Can the expiration date of a vaccine be extended?

Data demonstrating the stability of a vaccine, including potency data are required to determine the expiry. If a manufacturer wants to extend the dating period, it must submit data to FDA that includes, but is not limited to verification of the potency of the vaccine through the requested new expiry date. If the data demonstrate that the quality of the vaccine is not impacted, then following FDA approval, newly manufactured vaccines will be assigned the new expiry.


What is meant by lot release and what are the steps involved?

Because of the complex manufacturing process for most biological products, each lot undergoes thorough testing by the manufacturer. The manufacturer performs specific tests as specified in their license application. The manufacturer submits samples of each licensed vaccine lot and the results of their own tests for potency, safety, and sterility to the Agency. The manufacturer may not distribute a lot of the product into interstate commerce until CBER releases it. All vaccines are subject to lot release. The lot release program is part of FDA's multi-part strategy that helps assure biological product safety by providing a quality control check on product specifications.


Related Information

Related Links

Back to Top