(CNN) During a news conference Monday calling into question the safety of the Covid-19 vaccines, Republican Sen. Ron Johnson of Wisconsin again incorrectly used figures from an early warning system by the federal government to support his argument that vaccines may not be completely safe.
Johnson argued that while most people don't suffer significant side effects following vaccination, he is concerned about "that small minority that are suffering severe symptoms." He pointed again and again to the number of reported deaths in the federal Vaccine Adverse Event Reporting System in setting up his argument warning against the vaccines.
But, even while citing its figures, Johnson correctly said the system "does not prove causation or necessarily even correlation."
CNN fact-checked Johnson last month, when he made similar use of the Vaccine Adverse Event Reporting System numbers to support his argument that the vaccines might be more dangerous than was being reported. Here's what we found.
Facts First: Despite admitting that the Vaccine Adverse Event Reporting System does not show correlation or causation, Johnson's use of the system to suggest the Covid-19 vaccines are potentially dangerous is misleading and wrong. The system is not an official, vetted report of vaccine-related incidents. Anyone can submit a report and, as the system's website notes, "VAERS is not designed to determine if a vaccine caused a health problem" and "the reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable." Instead, the system allows the US Centers for Disease Control and Prevention and the US Food and Drug Administration to monitor for vaccine adverse events and conduct follow-up investigations.
When CNN asked the senator about his claims in May, Johnson's senior communications adviser Alexa Henning told CNN, "The senator is not suggesting the deaths were directly caused by the Covid-19 vaccine," adding that Johnson is instead calling for the submissions to the Vaccine Adverse Event Reporting System to be taken "seriously and research what is going on." Henning also noted Johnson's support for the development of Covid-19 vaccines under the Trump administration.
As the CDC notes, health care providers must report any death that follows a Covid-19 vaccination -- regardless of whether there's any suspicion the vaccine caused that death. The agency, along with the FDA, investigates each death reported to figure out whether it was caused by a vaccine.
From December 14, 2020, through June 21, more than 318 million doses of the vaccines have been given, the CDC website reports.
"During this time, VAERS received 5,479 reports of death (0.0017%) among people who received a COVID-19 vaccine," according to the CDC. The agency has found no causal link between the vaccines and these deaths.
"A review of available clinical information, including death certificates, autopsy, and medical records has not established a causal link to COVID-19 vaccines," the CDC says.
The CDC says it is plausible that one of the three vaccines being used in the US, made by Johnson & Johnson, may in rare instances cause a dangerous blood clotting condition called thrombosis with thrombocytopenia syndrome. At last report, it had killed three people out of more than 8 million vaccinated, and hematologists have been quick to point out that the risk of dying from a blood clot caused by a coronavirus infection is many hundreds of times higher than that. The CDC says the benefits of the vaccines greatly outweigh the risks.