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Double Check: How Does OpenVAERS Misrepresent Data?

Double Check: How Does OpenVAERS Misrepresent Data?

by Devika Khandelwal and Pallavi Sethi

So far, a total of 4.43 billion COVID-19 vaccines doses have been administered worldwide, according to the Financial Times. As several western countries, including the U.K. and U.S, rapidly inoculate people against COVID-19, global anti-vaccine messaging continues to sow fear. A widely used disinformation narrative includes misrepresenting publicly available data from websites such as U.S.’s Vaccine Adverse Event Reporting System (VAERS) and the U.K.’s Yellow Card scheme.

Posts on Twitter and TikTok commonly use claims such as “10,000 deaths” or “12,000 deaths” from the COVID-19 vaccines and attribute these figures to the VAERS or Yellow Card database. These kinds of claims are not just limited to people on social media. Far-right websites, including the Daily Expose and certain politicians have repeatedly made false assertions that COVID-19 vaccines cause deaths or serious injuries.

In May 2021, Republican Senator Ron Johnson of Wisconsin quoted figures from VAERS to falsely claim that three thousand people had died after receiving the COVID-19 vaccine. Meanwhile, in the U.K., Piers Corbyn, a leading voice in the anti-vax community, shared a misleading post on his Facebook page claiming that "people are now more likely to die from the COVID injections than any COVID flu." Similarly, Louise Hampton, a COVID-19 conspiracy theorist, stood outside a vaccination center and propagated disinformation narratives about the vaccine based on the Yellow Card scheme. In dismissing the vaccines’ success and misrepresenting figures from the official government database, Johnson, Corbyn, and Hampton mislead the public. Since these are self-reporting platforms, figures cited by the VAERS or the Yellow Card Scheme are unassessed and does not mean that the Centers for Disease Control and Prevention (CDC) or the U.K. government have investigated those figures and they are an accurate representation of post-vaccination fatalities or injuries. These figures do not necessarily imply that the vaccine caused the death and often include entries not yet confirmed or verified by the government agencies.

Along with statements from political figures and far-right activists, we found a few websites which repackage data from the VAERS official website and misrepresent them to mislead people. One such website we identified was OpenVAERS. OpenVAERS misrepresents data because it creates associations between two unrelated things. Such misrepresentations are easy when dealing with incredibly large numbers, such as the population of the entire U.S. For example, if you give everyone in the U.S. a lollipop and then publish data about how many of them die within 24 hours, you may create the false impression that lollipops are dangerous. The key thing to remember is that correlation does not mean causation, and until a link has been proven, such assumptions can be dangerous.

The CDC clearly states that COVID-19 vaccines are safe and effective, “under the most intense safety monitoring in United States history.” The CDC has investigated links between events reported to VAERS and the vaccines and found no relationships. 


VAERS was created in 1988 and is co-managed by the CDC and the U.S. Food and Drug Administration (FDA). The system was created “to detect possible safety problems in U.S.-licensed vaccines,” according to its website. The website further states that It is a “passive reporting system,” meaning that it depends on a person to report their post-vaccination experiences to the CDC and the FDA.

Anyone can report an adverse event to VAERS. Healthcare professionals must report certain adverse events, and vaccine manufacturers must report all adverse events that come to their attention. However, it is essential to remember that “VAERS is not designed to determine if a vaccine caused a health problem.” It is simply a self-reporting tool, which helps the CDC and the FDA detect “unusual or unexpected patterns of adverse event reporting that might indicate a possible safety problem with a vaccine.” The website encourages people to report any adverse event after administering a vaccine licensed in the U.S., whether it is or is not clear that a vaccine caused the adverse event. Investigations are only conducted on reports related to what the CDC considers a safety signal, i.e., “unusual or unexpected patterns of adverse events,” but updated or corrected data is not available to the public. 

VAERS accumulates this raw data and makes it available for anyone to download on their website. Since the data is raw and has not been assessed, VAERS’ website categorically states, “The reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable. In large part, reports to VAERS are voluntary, which means they are subject to biases. This creates specific limitations on how the data can be used scientifically. Data from VAERS reports should always be interpreted with these limitations in mind.” 

It has also published a guide to help people understand what this data means and how it should be interpreted. The guide also clearly states, “When evaluating data from VAERS, it is important to note that for any reported event, no cause-and-effect relationship has been established. Reports of all possible associations between vaccines and adverse events (possible side effects) are filed in VAERS.” 

It further states: “A report to VAERS generally does not prove that the identified vaccine(s) caused the adverse event described. It only confirms that the reported event occurred sometime after the vaccine was given. No proof that the event was caused by the vaccine is required in order for VAERS to accept the report. VAERS accepts all reports without judging whether the event was caused by the vaccine.” There have also been several welcoming outcomes from using VAERS; reports submitted to VAERS are reviewed by experts, like doctors, pharmacists, and statisticians, and serious events are given additional scrutiny. VAERS initially detected a dangerous intestinal obstruction linked to RotaShield, a rotavirus vaccine subsequently withdrawn from the market by its manufacturer.

The adverse events reported through VAERS may or may not be related to the vaccine, and a correlation does not mean causation. 

According to the CDC website, “VAERS received 6,490 reports of death (0.0019 percent) among people who received a COVID-19 vaccine. A review of available clinical information, including death certificates, autopsy, and medical records, has not established a causal link to COVID-19 vaccines. However, recent reports indicate a plausible causal relationship between the J&J/Janssen COVID-19 Vaccine and TTS, a rare and serious adverse event—blood clots with low platelets—which has caused deaths.” 

Heidi Larson, director of the Vaccine Confidence Project at the London School of Hygiene & Tropical Medicine told Science, “for those who are out to scare, there’s a lot of material out there” referring to the VAERS database. She further says, “CDC and the public health community need to make a serious investment right now to more aggressively counter the misuse of VAERS data, for example by responding as quickly as possible to new myths that are gaining traction, and doing so in lay-friendly language and forums rather than arcane medical journals. At least make sure you get the right information out there as soon as possible. Watch how people misinterpret [VAERS data] … because it’s clearly being misinterpreted.”

Despite this, VAERS data is used by vaccine skeptics to stoke fear in people around COVID-19 vaccines. The fact that the VAERS website repeatedly states that the data is unverified is often ignored. False narratives citing VAERS data can be found on several social media platforms like Twitter, Facebook, and TikTok. A simple search for #vaersdata gives such results on TikTok. 


Vice reported that in 2004, anesthesiologist James Laidler submitted a report to VAERS. After he got his annual influenza vaccine, Laidler wrote that his muscles began to grow in size, his skin became green, and he turned into the Incredible Hulk. His aim when submitting this report was to show that while one can submit any reaction to VAERS, the data available has several limitations. There is a need for caution when interpreting the data. 

Yellow Card Scheme

Following the thalidomide tragedy, which included an adverse drug reaction that killed thousands of babies, the Yellow Card scheme was introduced in 1964 by Dr. Bill Inman.

The Yellow Card scheme, governed by the Medicines and Healthcare products Regulatory Agency (MHRA), accumulates and monitors data on safety concerns, including "suspected side effects or adverse incidents involving medicines and medical devices." Before 1990, only doctors reported adverse incidents. However, the system now relies on "voluntary reporting of suspected side effects" by public members, including patients, pharmacists, and parents. 

The primary goal of the Yellow Card system is to "provide an early warning" regarding the safety of a medical device so that further investigation can take place. The MHRA initiates an investigation after a review and analysis of the reported data. The MHRA further generates a weekly summary of the reporting and publishes it on its website. 

It is vital to note that reported side effects on the Yellow Card scheme are proven and not potential side effects of vaccines. While anybody can self-report suspected side effects through the Yellow Card, the website clearly states "reported events are not always proven side effects." The MHRA says that when millions of people, including those with an underlying health condition and older people, get vaccinated, some natural adverse events occur regardless of the vaccine. 

For example, a Twitter user posted this thread where they show the different events reported to the Yellow Card Scheme. One glance tells you that some of the reported side effects could have no relation to a COVID-19 vaccine, like rabies, screaming, or growth of eyelashes. So many people who cite this data to back their argument that “vaccines are dangerous” do not necessarily filter these unrelated events out and make outlandish claims. 

Sarah Caul, the head of mortality analysis at the Office for National Statistics (ONS) revealed the vaccine-related mortality figures from the ONS data on Twitter. The ONS counts vaccine-related deaths if adverse events to the vaccine are mentioned on the death certificate. 

According to her, up to June 2021, there were four deaths where the adverse reaction was mentioned on the death certificate. However, none had the reaction to the vaccine as the underlying cause of death. 

Speaking to Logically, Caul explained that the ONS mortality data can take “weeks or months” as the coroner uses their “medical expertise to decide the cause based on symptoms, physical examination, hospital records, laboratory tests.” Once the coroner provides a verdict, the Coroner’s Court follows legal rules of evidence in that the vaccine reaction is recorded on the death certificate if it plays “a part in the chain of cause of death that led to the death.”

Since vaccine-related mortality data from the ONS goes through rigorous verification by a medical professional, the figures are more accurate than the Yellow Card data. 

One of the most prominent anti-vax and anti-COVID-vax narratives is that COVID-19 vaccines are unsafe because they were not tested properly, a claim which is untrue. According to the FDA, “have been thoroughly tested and found to be safe and effective in preventing severe COVID-19. They continue to undergo continuous and intense safety monitoring.” The vaccines are deemed highly effective in preventing serious disease, hospitalization, and death from COVID-19 and their benefits outweigh their risks. 

The anti-vaccine community often cites figures from the VAERS and Yellow Card scheme. However, even when these figures are correct, they cherry-pick data from the government database, make unsubstantiated connections, and repackage this data to fuel vaccine hesitancy. This narrative comes from a lack of understanding of how the government database works. Both VAERS and Yellow Card encourage people to report any medical events post-vaccination, however vague or disconnected they may be. But these reports do not prove causality. When the reports are uploaded, they are investigated by authorities to determine causality, so the unassessed data cannot be used to draw conclusions. These reports are usually used by authorities to determine unexpected patterns of health problems, but that can only be done once they investigate the data. 

By failing to disclose the difference between potential and proven side effects, the propagators of COVID-19 disinformation mislead the public and cause vaccine scaremongering. 

Read our investigation revealing the person behind OpenVAERS here

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