In a forthcoming publication, Timothy Caulfield, a health law and policy professor at the University of Alberta and a serial debunker, outlines the state of the science. He has found that fears of backfire effects are overblown and that there is a growing body of evidence that suggests correcting misinformation is in fact an important health policy activity. But the timing and type of counter-messaging really matters. He lists some actions to take: Use facts, avoid jargon, find trustworthy sources, lead with the corrective information. And some to avoid: Don’t shame, ridicule, or marginalize; don’t target hard-core believers; aim for the general public instead.
But much of the evidence that countering misinformation can change people’s minds comes from studies of less politically and emotionally charged misinformation than vaccines. And these sorts of tactics don’t yet have a proven track record when it comes to changing anti-vaccine sentiment, as Nyhan points out. “We still don’t know very much about how effective any kind of pro-vaccine messaging is at changing people’s behavior,” he says. At most, public policy researchers have been able to assess how parents’ attitudes change in response to different communication strategies. But connecting the dots between survey results and any changes in vaccination rates has been much harder.
Nyhan, who’s written extensively about when it’s appropriate for the media to cover misinformation, worries that a campaign like PGP’s might inadvertently do more harm than good, not because of the backfire effect but because social media algorithms feed off of controversy. “In trying to correct misinformation, are you actually creating the kind of engagement that causes platforms to amplify those messages to more people who otherwise wouldn’t see it?” he asks.
How effective PGP’s approach turns out to be will depend a lot on the specific messaging the group encourages its volunteers to propagate, says Nyhan. For example, he says, if they could rally people to advocate for closing vaccine-exemption loopholes in state policies, that could go a long way. Such laws make it harder for parents to seek nonmedical exemptions to vaccinating their children who attend public schools. They’ve also become a political flashpoint, galvanizing new ranks of anti-vaccine activists. In a hyper-partisan 2015 vote, California did away with exemptions for religious and personal beliefs. In the following years, the rate of vaccinated kindergarteners crept steadily upward. But by 2019, the state’s vaccination rates slipped again, as parents found other ways of opting out.
Last year Nyhan argued in The New York Times that the focus on anti-vaccine content on social media can obscure a robust body of research that shows the rates of unvaccinated children correlates most closely to a state’s vaccine requirement policies. In other words, policy matters more than public persuasion. That’s why he’s skeptical that an approach like PGP’s is going to make much of a dent.
It’s a sentiment Nowak shares. “Battling these people in these online spaces may have some value, but I’m not sure it’s going to have as much impact as reaching pregnant mothers with good information or tightening vaccine exemption laws,” says Nowak. “That’s where we can really make a difference, not in some Twitter war.”
They also worry that a campaign like Stronger could distract from a much bigger vaccination crisis. In the last three months, vaccination figures have plummeted, both in the US and abroad—not because of viral conspiracy theories but because of an actual virus: SARS-CoV-2. The novel coronavirus—which has killed more than 400,000 people globally, and infected nearly 7.5 million—has diverted critical public health resources away from vaccination programs. Amid the pandemic, parents are also keeping their kids home, fearful of going to the doctor’s office where they might catch Covid-19. According to a recent report by the CDC, pediatricians’ orders for all non-influenza vaccines declined by more than 3 million doses from March 13 to April 13 compared with the same period last year. Internationally, the picture is equally grim. With mass immunization programs paused in at least two dozen countries, the World Health Organization estimates more than 100 million children worldwide could be vulnerable to measles.