Researchers recently proposed that open communication about a national vaccine safety reporting system could improve public trust that vaccines are safe. They thought this strategy could improve vaccine acceptance.
That doesn’t turn out to be the case.
The Vaccine Adverse Event Reporting System (VAERS) collects information about possible side effects that may occur after inoculation. Developed by the Centers for Disease Control (CDC) and available online, anyone can report possible adverse reactions to vaccines for any reason, making it a rich source of information about possible vaccine harms.
“One of the issues in vaccine acceptance is trust,” says Laura Scherer, assistant professor of psychological sciences at the University of Missouri. “Individuals, parents, and vaccine opponents lack trust that doctors and the government have done sufficient research to validate the safety of vaccines. By educating participants about the VAERS system, we thought that this might increase trust that the Centers for Disease Control are doing everything that they can to research and document vaccine harms.”
Using data on serious adverse events reported for the Human Papillomavirus vaccine in VAERS in 2013, the researchers surveyed more than 1,200 participants’ reactions to the VAERS reports.
“Stories about vaccine harms can influence vaccine acceptance even when people don’t completely believe them.”
The first group was presented with the standard HPV vaccine statement that all patients receive prior to vaccination. The second group was given the same vaccine statement as well as information about VAERS, which included data showing that out of approximately 10 million vaccinations, 24 individuals were reported to have been disabled and seven were reported to possibly have died as a result of their vaccinations. The third group received this VAERS information and also read the detailed reports of each event.
“Since anyone can report anything to VAERS for any reason, the VAERS reports contain incidents of serious adverse events that may not have anything to do with the vaccine,” Scherer says. “We thought that by having people read the actual reports, they would see that there are very few reported serious events, and that the vaccine may not have even caused the event. Taken together, we felt this might make participants feel more assured that vaccines are safe—but in fact, what we found was the opposite.”
Results showed that participants who were educated about the VAERS system and who were given summary data about adverse events had slightly more vaccine acceptance compared to those who received the vaccine statement alone. However, exposure to detailed incident reports significantly reduced vaccine acceptance and trust in the CDC’s declaration that vaccines are safe.
“When participants read the incident reports, there was a marked reduction in their willingness to vaccinate—even though most participants believed the vaccines caused few or even none of the deaths,” Scherer says. “Stories about vaccine harms can influence vaccine acceptance even when people don’t completely believe them. This can potentially inform how people react to stories versus data about vaccine harms and provides a test of publicly available data on vaccine acceptance.
“It also means that the media should be very careful about propagating stories about vaccine harms when it is unclear that the vaccine was the cause.”
The study appears in the journal Vaccine. Scherer’s coauthor is Victoria Shaffer, associate professor of psychological sciences and an associate professor of health sciences in the University of Missouri School of Health Professions.
Source: University of Missouri