Under the guise of “just asking the questions,” Republican Sen. Ron Johnson of Wisconsin spread anti-vaccine misinformation on a right-wing radio show Thursday, questioning why efforts were being made to vaccinate the general US population, especially young people and those who had previously been infected with Covid-19. Johnson, who tested positive for coronavirus last fall, said he was “sticking up for people who choose not to get vaccinated.” As of March, Johnson told CNN he had not yet been vaccinated because he previously had Covid-19. In Thursday’s interview with conservative radio host Vicki McKenna, Johnson suggested there have been thousands of deaths connected to Covid-19 vaccinations and that receiving a vaccine could be particularly dangerous for those who had previously been infected. Vaccinations and deaths To defend his position and call into question the safety of Covid-19 vaccines, Johnson cited numbers from the federal Vaccine Adverse Event Reporting System (VAERS), which allows anyone to submit a report. Johnson said that according to the system, “we’re over 3000 deaths after within 30 days of taking the vaccine,” suggesting these deaths were tied to Covid-19 vaccines. Facts First: Johnson’s insinuation that these reported deaths are tied to Covid-19 vaccines is entirely false. VAERS 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 US Food and Drug Administration to monitor for vaccine adverse events and conduct follow-up investigations. Johnson’s senior communications adviser Alexa Henning told CNN in an email Friday evening, “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 VAERS 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. The agency, along with the FDA, investigate each death reported to figure out whether the death was caused by a vaccine. From December 14, 2020, to May 3, more than 245 million doses of the vaccines have been given, the CDC website reports. “During this time, VAERS received 4,178 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 coronavirus infection is many hundreds of times higher than that. The CDC says the benefits of the vaccines greatly outweigh the risks. Vaccination following a Covid-19 infection The Wisconsin Republican also claimed there’s a risk of death if individuals who previously tested positive for Covid-19 receive a vaccine. “I’m talking to doctors who have, since day one, been concerned about vaccinating people who’ve already had Covid, because you die, not of Covid, you die of the immune system overreaction to Covid,” Johnson said. “So there’s a concern there.” Facts First: This is wrong. The vaccines currently being administered in the US are considered safe and recommended even for individuals who were previously infected with Covid-19. The CDC recommends individuals be vaccinated regardless of whether they already had Covid-19 “because experts do not yet know how long you are protected from getting sick again after recovering from COVID-19.” Early studies suggest individuals who were previously infected with the virus may only need one dose of certain Covid-19 vaccines. Dr. Walter Orenstein, associate director of the Emory Vaccine Center, told CNN he was “not aware of any data to support Senator Johnson’s allegation.” “An ‘overreaction of the immune system’ appears to be one of the ways natural Covid-19 infection leads to serious illness and death. There is the theoretical risk that vaccines might trigger that, but I am not aware of any data to date that support an actual role for vaccines in exacerbating the clinical illness,” Orenstein said. “In fact, the trials showed that the vaccines, such as the J&J vaccine, are more effective against serious disease than mild disease. ” According to Jennifer Grier, a clinical assistant professor of immunology biomedical sciences at the University of South Carolina, vaccines add a level of protection above and beyond the body’s response to an infection. “The problem is that not everyone will develop immunity after a SARS-CoV-2 infection,” Grier wrote in an article for The Conversation. “For people who do develop immunity, the strength and duration of the protection can vary a lot.” New research from the Penn Institute of Immunology suggests vaccine side effects such as a sore arm, fever or muscle aches are a sign of a positive immune response and should not be a cause for concern. “Everyone has good responses to the vaccines. They work to protect people against COVID-19. But for those who may be worried about side effects, they are not necessarily a bad thing—they may actually be an indicator of an even better immune response,” said E. John Wherry, director of the Penn Institute of Immunology in the Perelman School of Medicine at the University of Pennsylvania and senior author of the report, in a press release about the report.