Vaccine injuries and side effects should be reported to Vaccine Adverse Event Reporting System (VAERS).
Reporting Side Effects to VAERS
The CDC advises that “all significant adverse events that occur after vaccination of adults and children, even if you are not sure whether the vaccine caused the adverse event.”
Are they?
Unfortunately, no.

While both doctors and parents can report these side effects, they don’t always get reported.
Underreporting of Side Effects to VAERS
Still, although reports to VAERS are underreported, they are almost certainly not underreported by as much as some folks believe.
Have you heard the claim that only 1% of serious vaccine reactions are reported to VAERS?
That’s not true.
That claim is based on an old study about drug reactions and was not specific to vaccines.
We also know that underreporting is less common for more severe adverse reactions than for those that are more mild. For example, one study found that up to 68% of cases of vaccine-associated poliomyelitis (a table injury) were reported to VAERS, while less than 1% of episodes of rash following the MMR vaccine were reported.
That’s not to say that only severe or serious adverse reactions should be reported.
But since VAERS watches “for unexpected or unusual patterns in adverse event reports,” it still works even if each and every side effect isn’t reported.
VAERS Works
Reports to VAERS are underreported.
VAERS still works well though.
Again, that’s because VAERS doesn’t need each and every adverse event to be reported for the system to work and to help it identify vaccines that might not be safe.
“Despite its limitations, VAERS effectively detected a possible problem soon after introduction of RRV-TV in the United States.”
Lynn R. Zanardi, et al on Intussusception Among Recipients of Rotavirus Vaccine: Reports to the Vaccine Adverse Event Reporting System
We saw that with the RotaShield vaccine. After nearly 20 years of research, the first rotavirus vaccine was approved by the FDA on August 31, 1998. About seven months later, in March 1999, the ACIP published their formal recommendations that all infants get RotaShield on a three dose schedule, when they are two, four, and six months old.
By June 11, 1999, VAERS had received 12 reports of intussusception related to the RotaShield vaccine and by July 13, its use was temporarily suspended, as the CDC continued to investigate.
Once the CDC announced the temporary suspension, even more reports of intussusception after RotaShield were made to VAERS. Those extra reports likely mean that intussusception was being underreported initially, but it still triggered the temporary suspension and extra studies that eventually got the manufacturer to withdraw the vaccine.
“VAERS is used to detect possible safety problems – called “signals” – that may be related to vaccination. If a vaccine safety signal is identified through VAERS, scientists may conduct further studies to find out if the signal represents an actual risk.”
CDC on How VAERS is Used
Early signals in VAERS also helped detect a very small increase in the risk of febrile seizures among toddlers who got the 2010-11 flu vaccine combined with either Prevnar or a DTaP vaccine.
Also keep in mind that VAERS isn’t the only system that helps to monitor vaccine safety. We also have the Vaccine Safety Datalink project, the Clinical Immunization Safety Assessment Network, and the Vaccine Analytic Unit.
What to Know About Underreporting of Side Effects to VAERS
Even though underreporting of side effects to VAERS is an issue, because VAERS works by looking at early signals and trends, it still works well to identify possible safety problems from vaccines.
More About Underreporting of Side Effects to VAERS
- 100 bad arguments against vaccines
- VAERS a Few Things We Need to Discuss
- On “Vaccine Injury”: Real, but Exceedingly Rare
- Vaccine Adverse Event Reporting System (VAERS) Usefulness and Limitations
- CDC – Surveillance for Adverse Events Following Immunization Using the Vaccine Adverse Event Reporting System (VAERS)
- CDC – Rotavirus vaccine for the prevention of rotavirus gastroenteritis among children. Recommendations of the Advisory Committee on Immunization Practices (ACIP)
- Study – Safety monitoring in the Vaccine Adverse Event Reporting System (VAERS)
- Study – Intussusception Among Recipients of Rotavirus Vaccine: Reports to the Vaccine Adverse Event Reporting System
- Study – Using electronic medical records to enhance detection and reporting of vaccine adverse events
- Study – The reporting sensitivities of two passive surveillance systems for vaccine adverse events
- Study – Understanding vaccine safety information from the Vaccine Adverse Event Reporting System
- Study – Surveillance for safety after immunization: Vaccine Adverse Event Reporting System (VAERS)–United States, 1991-2001
- Study – An overview of the vaccine adverse event reporting system (VAERS) as a surveillance system. VAERS Working Group
- Study – Deaths following vaccination: What does the evidence show?
- Debunking anti-vaccine arguments: VAERS, package inserts, and the VICP do not prove that vaccines are dangerous
- Gold mine or dumpster dive? A closer look at adverse event reports
- How vaccine litigation distorts the VAERS database
- The Incredible Hulk Vaccine Side Effect: Or, Understanding VAERS
- Vaccine Injuries from The MMR, A Review of VAERS
- VAERS as “evidence” of vaccine harm
- On Using VAERS
- Reports of vaccine related effects can be useful
- VAERS a Few Things We Need to Discuss
VAERS works, right? So why are the 400 plus deaths after MMR vaccine simply ignored? More people die after MMR vaccine than from any of the 3 things that the vaccine is designed to prevent. Nearly no ones dies from measles… it’s something like 1 out of 1600 or something… sounds like a lot except so few people get measles, the number is almost too small to calculate a percentage that die from measles (percentage of population). If VAERS actually meant something to anyone, they would see the deaths after vaccination and take it serious. But the people in charge of making and selling vaccines don’t want the 400 plus deaths to be considered, or even mentioned. No one would get the MMR vaccine if they were told the truth about it.
Just the comment by the author that adverse reactions are uner reported,but VAERS still works well is all I need to know about how credible this report is
So I’m guessing Vaxopedia is funded/written by the pharmaceutical industry….
The Stanford U. study told us that only about 1% of all vaccine injuries are reported.So the almost 6,000 figure of deaths in the U.S. can have two extra zeros added.And let’s say that study is off by 50%,that’s still a staggering amount of vaccine deaths(over 10,000 and climbing in Europe).In /76 the new(then ) Swine Flu vaccine killed 25 people and was immediately halted.How low have we devolved to think the amount of deaths due to these unapproved,DNA altering vaccines is acceptable?
“We also know that underreporting is less common for more severe adverse reactions than for those that are more mild. For example, one study found that up to 68% of cases of vaccine-associated poliomyelitis (a table injury) were reported to VAERS, while less than 1% of episodes of rash following the MMR vaccine were reported.”
Seems to me the study is showing some data for a specific adverse event and you’re trying to use that to make broad, sweeping generalizations.
“Have you heard the claim that only 1% of serious vaccine reactions are reported to VAERS? That’s not true. That claim is based on an old study about drug reactions and was not specific to vaccines.”
It’s not true because the study is old? It’s not true because the study was on a specific drug instead of vaccine? You seem to make assumptions to create a dishonest frame.
This is the source is it not? page 6: lazarus-final-report-2011.pdf
I see it specifically referring to vaccines.