Post-license monitoring for vaccinations

Perhaps the greatest success story in public health is the reduction of infectious diseases resulting from the use of vaccines. Yet, we know some patients have reactions that may be caused by the vaccine, and many of the side effects occur after a vaccination and it’s not by mere coincidence. Therefore, scientific research that attempts to distinguish true vaccine side effects from unrelated, chance occurrences is crucial. This knowledge is necessary to maintain public confidence in immunization programs. So what exactly is being done to make sure that the vaccines continue to be effective and safe?

Before vaccines are licensed by the FDA, they are tested extensively in the laboratory and with human subjects to ensure their safety to the general public. This process is called pre-licensing.

The CDC website states, “Vaccine licensing is a lengthy process that may take 10 years or longer. The FDA requires that vaccines undergo three phases of clinical trials with human subjects before they can be licensed for use in the Phase one trials are small, involving only 20 to 100 volunteers, and last only a few months. The purpose of phase one trials is to evaluate basic safety and identify very common side effects. Phase two trials are larger and involve several hundred participants. These studies last anywhere from several months to two years and collect additional information on safety and efficacy. Data gained from phase two trials can be used to determine the composition of the vaccine, how many doses are necessary, and a profile of common side effects. Unless the vaccine is completely ineffective or causes serious side effects, the trials are expanded to phase three, which involves several hundred to several thousand volunteers. Typically these trials last several years. Because the vaccinated group can be compared to those who have not received the vaccine, researchers are able to identify true side effects.”

After a vaccine is licensed for public use, its safety is monitored continually. The FDA requires all manufacturers to submit samples from each vaccine lot prior to its release. In addition, the manufacturers must provide the FDA with their test results for vaccine safety, potency, and purity. Each lot must be tested because vaccines are sensitive to environmental factors like temperature, and can be contaminated during production.

During the last 10 years, the FDA has recalled only three vaccine lots: one was mislabeled, another was contaminated during production, and the third was recalled after the FDA discovered potential manufacturing problems at a production plant.

While clinical trials provide important information on vaccine safety, the data are somewhat limited because of the small number (hundreds to thousands) of study participants. Rare side effects and delayed reactions may not be evident until the vaccine is administered to millions of people.

Therefore, the federal government established a surveillance system to monitor adverse events following vaccination. This project is known as the Vaccine Adverse Event Reporting System (VAERS). More recently, large-linked databases containing information on millions of individuals have been created to study rare vaccine adverse events.

The National Childhood Vaccine Injury Act of 1986 requires health care providers to report certain adverse events that occur following vaccination. As a result, the Vaccine Adverse Event Reporting System was established by CDC and FDA in 1990. VAERS provides a mechanism for the collection and analysis of adverse events associated with vaccines currently licensed in the United States. Adverse events are defined as health effects that occur after immunization that may or may not be related to the vaccine. VAERS data are monitored continually to detect unknown adverse events or increases in known side effects.


You Only Have Three Years To File Your Claim

The first step in helping yourself or a loved one after a serious vaccine related injury is to contact us for a free review of your case.

Recent Posts