Understanding Vaccine Hesitancy In Pursuit Of Widespread Immunity

In a recent Texas A&M University-led study, about 31 percent of 5,009 surveyed Americans said they don’t plan to get the COVID-19 vaccine once it becomes available to them.

Experts say between 70 to 90 percent of the population needs to be vaccinated in order for herd immunity to end the pandemic that’s caused the deaths of more than half a million Americans in the last year. So even as the rollout picks up speed, with President Joe Biden announcing on Thursday a plan to make all adults eligible for the vaccine by May 1, vaccine hesitancy could stand in the way of reaching herd immunity.

A combination of skepticism, misinformation and political polarization may influence the willingness of millions of people to accept vaccination. Polling from the Kaiser Family Foundation currently shows that 15 percent of Americans “definitely will not get vaccinated.”

Timothy Callaghan, who led the Texas A&M survey that was published in January in Social Science & Medicine, has studied vaccine hesitancy since he joined the School of Public Health in 2016 as an assistant professor in the Department of Health Policy and Management. Prior to the novel coronavirus, he says there was already a clear correlation between partisanship and vaccine hesitancy, and a profile for groups who are more likely to refuse vaccination.

“We already had a pattern of vaccine hesitancy before the pandemic,” Callaghan said. “But then the politicization that happened with COVID-19 and the response to COVID-19 sort of accelerated vaccine hesitancy.”

The willingness of millions of people to be vaccinated may determine how long it will take for society to return to some semblance of pre-pandemic normalcy. And when it comes to vaccines, a difference of opinions could have immediate – and potentially fatal – consequences.

“The vaccines won’t help us get back to normal if we can’t get enough people to take them,” said School of Public Health Dean Shawn Gibbs. “The only way to get there is vaccine uptake.”

What Causes Vaccine Hesitancy

Gibbs said Callaghan’s research has played an important role in helping the School of Public Health identify groups who could benefit from more information and education on the issue.

“It’s letting us drill down into the populations that we need to increase messaging for, and really starting to get an understanding of the mis-messaging that’s out there in order to counter it,” he said.

Respondents to the survey Callaghan led answered a series of questions about their behaviors and attitudes about COVID-19, including why they did or did not intend to pursue vaccination. The results showed that politics plays a crucial role: each one-point increase in conservatism increases the odds of vaccine refusal by 18 percent. People who said they intended to vote for Donald Trump in the presidential election – the survey was conducted in mid-2020 – were 29 percent more likely to refuse vaccination.

Callaghan said people with conservative ideology tend to be more hesitant than liberals – which correlates with the fact that those who are vaccine hesitant tend to be less trusting of scientists. However, it’s an issue that spans the political spectrum.

On one side, the Trump administration downplayed the severity of COVID-19 “while simultaneously denigrating scientists,” Callaghan said. Meanwhile, President Joe Biden and Vice President Kamala Harris indicated on the campaign trail that they would not trust a vaccine produced under the Trump administration, which he said sowed doubt among liberals.

“If you look at the data and compare the levels of vaccine hesitancy in May to last September, it spiked about 20 percent across liberals and conservatives,” Callaghan said. “Both sides were getting information from an environment clouded by a lot of things.”

Politics alone is not to blame.

Following Andrew Wakefield’s controversial paper in The Lancet in the 1990s, Callaghan said there’s always been an undertone of conspiratorial thinking among some individuals who are vaccine hesitant. In the COVID-19 era, more people are “paying attention and looking for as much information as they possibly can,” he said.

“With other vaccines, it’s well established. The flu vaccine is not novel. The MMR vaccine is not novel,” Callaghan said. “However, COVID-19 vaccines are brand new, so everyone out there is looking for information, and given the environment we have today where information both true and not true is very easy to access, more people are going to be exposed to conspiracy theories about vaccines than they would be in a normal circumstance.”

He said African Americans are already significantly more likely to refuse vaccination due to distrust of the medical establishment, the result of decades of historical medical abuses against Black people. Callaghan also noted that anti-vaccine advocacy groups have made a concerted effort to target this group by framing the COVID-19 vaccine in terms of past medical abuses against Black Americans, for example invoking the Tuskegee Syphilis Study conducted by the United States Public Health Service over 40 years.

Black survey respondents were 41 percent more likely not to pursue vaccination, according to the study. Vaccine refusal was found to be even higher among women, at 71 percent. Women said they were hesitant based on safety concerns and the effectiveness of the vaccine. The Black respondents, meanwhile, said their hesitancy also stemmed from a lack of financial resources or health insurance.

Building Trust In Vaccines

While a profile has been established of who is likely to get vaccinated, Callaghan said it will still be a challenge to use that set of correlates to determine how best to persuade people to get the shot.

Convincing more people to be accepting of science without alienating them in the process is “the true question that a lot of scientists are looking at right now,” he said.

“Just telling people that they’re wrong and you should change your behavior is not a good way to change minds,” Callaghan said. “Right now what we’re focused on in the scientific community is trying to understand both which messages are going to be most effective in convincing people to vaccinate as well as which messengers.”

Conservatives, for example, would likely be more open to listening to conservative politicians, members of their local community or religious leaders than a scientist or bureaucrat from the Biden administration.

There’s currently more demand than supply, so Callaghan said the full extent of hesitancy won’t be known until early summer. He says the good news with COVID-19 vaccination is that many people are taking a “wait and see approach,” and may be more willing to get vaccinated after they see loved ones go through the process. Callaghan is also encouraged by vaccination capacity and the one-dose Johnson & Johnson vaccine.

“So am I encouraged by what I’m seeing so far? Yes, but what will really be telling is in a few months once we have enough vaccines for everyone who wants to be vaccinated and how much work we have to do to still get to our herd immunity,” he said.

Callaghan, a political scientist, is among the leading experts from disciplines spanning public health, law, epidemiology and nursing selected for the Lancet‘s Commission for Vaccine Refusal, Acceptance, and Demand in the USA.

Led by Dr. Peter Hotez, dean of the National School of Tropical Medicine at the Baylor College of Medicine and a fellow of Texas A&M’s Hagler Institute for Advanced Study, the commission is tasked with compiling a report on vaccine hesitancy in the United States. Callaghan said the goal is to understand who’s likely to be vaccine hesitant and why, and make recommendations for improving vaccine acceptance.

As for Texas, Gibbs said he’s “a little uneasy” about vaccination rates. According to state data, about 9 percent of the population was fully vaccinated as of March 11.

“As soon as you are eligible and as soon as you are able, go and get this vaccine,” Gibbs said. “A lot of hard work has been put in to making sure that this is a safe and effective vaccine, and everything we’re seeing is indicating that this is just that.”

The university is advocating for the campus community to get vaccinated as soon as possible, he said. For students, that might be in the summer, but a forthcoming National Institutes of Health study by Texas A&M epidemiologist Rebecca Fischer will allow for the vaccination of up to 1,000 students to monitor the reduction of virus spread.

While some may be hesitant about potential side effects, Gibbs said the reactions are a sign of the body’s immune system being engaged to fight the virus. The Centers for Disease Control and Prevention says that people may experience some pain, redness and swelling of the vaccine site, and other symptoms may include fatigue, headache, muscle pain, chills, fever or nausea.

Callaghan says more severe side effects are extremely rare, and those that are experienced by the vast majority of people typically go away within a few days. And while some people may be infected after receiving the vaccine, Gibbs said the health impacts are much lower on those people than for individuals who are not vaccinated.

It’s a necessary step everyone must take to help the world “return to normal,” Gibbs said.

“If we want to have a full house at Kyle Field and if we want to have the kind of events that we normally have on campus in fall and spring, we need large-scale vaccine uptake across the entire population, and that includes the student body,” he said.