Study: Peer Modeling with Psychological Inoculation Can Promote COVID-19 Vaccinations


covid-19 vaccines peer modeling with psychological inoculation study2
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COVID-19 vaccination is often deterred by misinformation, from conspiracy theories to exaggerated side effects on social media.

Vaccine misinformation is potent among Latinos due to lack of reliable information that is culturally relevant or in Spanish, along with little government outreach.

That is why UT Health San Antonio researchers studied a new type of advertisement on Facebook to push people to get vaccinated.

They used video testimonial ads of Latino peer role models, like Rosa Herrera, who tout the benefits of the COVID-19 vaccine, while providing psychological inoculation by acknowledging misinformation, rejecting it, and receiving the vaccine.

Compared to generic vaccine promotion ads from the CDC, the Latino peer model ads yielded a significantly higher rate of link clicks on Facebook to “find a vaccine near you,” according to a new study in the journal Health Education Research.

“This provides useful data that theory-based communication—peer modeling with psychological inoculation—may be more effective than more traditional forms of advertising for promoting coronavirus vaccination,” said Dr. Amelie G. Ramirez, study lead author and leader of the Salud America! Latino health national program, chair of the Department of Population Health Sciences, and director of the Institute for Health Promotion Research at UT Health San Antonio.

Why Did the Researchers Decide to Address COVID-19 Vaccine Misinformation?

Ramirez and her team at UT Health San Antonio know that COVID-19 vaccines are safe, effective, and free. Vaccination helps our bodies build immunity and protection against disease, preventing us from getting severe illness or death.

But Latinos are less likely than their peers to get vaccines, including those for influenza, HPV, and now COVID-19.

4 Compelling Communication Strategies to Build COVID-19 Vaccine ConfidenceTheir reasons for vaccine uncertainty vary.

They include concerns about perceived safety, considering immunization a low priority, perceived low risk of illness, limited knowledge about the disease or the benefits of vaccination, limited health literacy, difficulty accessing services, clinician and cultural bias, immigration status, and more.

As of late May 2021, 67% of unvaccinated adults heard at least one COVID-19 vaccine myth and believed it to be true or were not sure.

The U.S. Surgeon General called health misinformation an urgent threat to public health.

Misinformation about COVID-19 and vaccines also often targets Latino and Black communities, said Dr. Patricia Chalela, a co-author of the new study and associate professor at the Institute for Health Promotion Research at UT Health San Antonio.

“Some common information spreading through social media among Latinos include conspiracy theories that the COVID-19 vaccine contains a microchip that will be used to track individuals, will be used to eliminate parts of the population, will alter people’s DNA, and even cause vaccinated persons’ skin to shed,” Chalela said. “In addition to wild exaggerations of potential side effects, religious beliefs are also keeping some Latinos from getting vaccinated, including believing that God will cure COVID-19, and that the only cure needed is the church.”

How Did the Researchers Counter COVID-19 Vaccine Misinformation?

To move Latinos from COVID-19 vaccine uncertainty to vaccine confidence, Ramirez, Chalela, and their team at Salud America! at UT Health San Antonio are uplifting the “Change of Heart” vaccine hero stories and videos of real Latinos who overcame misinformation, got the shot (Pfizer-BioNTech, Moderna, Johnson & Johnson), reconnected with family, and are helping end the pandemic and variants like Omicron.

Read and watch the stories here.

Two key elements of these stories are:

jesus larralde peer modeling with psychological inoculation covid-19 vaccinesPeer modeling. This uses real stories about real people to present information for imitation by those who read or observe them. Peer modeling has a foundation in Albert Bandura’s social cognitive theory—that humans mainly learn is by observing others around them.

Psychological inoculation. “In psychological inoculation, existing or anticipated persuasive arguments against a desired belief are explicitly presented and refuted before or after people are exposed to misinformation. Prior research has shown that inoculating messages from trusted sources can prevent belief in new conspiracy theories, increase vaccine intentions, and activate protective responses, such as critical thinking when exposed to future COVID-19 misinformation,” according to Ramirez’s team.

For example, Salud America! produced a story and video of Rosa Herrera, a Latina grandmother.

In the materials, Herrera shares how she became reluctant to obtain vaccination when she read on Facebook that the COVID-19 vaccine would inject her with a microchip to track her.

Herrera explains she learned that was not true by watching a webinar with public health experts who explained the vaccine. She decided, despite misgivings about misinformation, to get the shot. Herrera wanted to make sure her daughters, who had gotten COVID-19, didn’t get sick again from her. She also wanted to safely visit family who live in Mexico.

“I’m able to see my grandkids and my kids. It gives you more freedom,” Herrera said. “If you don’t do it for yourself, do it for your family.”

How Did the Researchers Use Peer Models with Psychological Inoculation to Spur Vaccine Action?

Ramirez, Chalela, and their team wanted to test if “Change of Heart” vaccine hero stories and videos could compel vaccination.

The team included: Ramirez, Chalela, Edgar Munoz, statistician, Cliff Despres, communications director, and Julia Weis, program coordinator, all of UT Health San Antonio; Alfred McAlister of the UT School of Public Health – Austin Regional Campus; and Pramod Sukumaran, formerly of UT Health San Antonio.

They did a test via Faceook advertising to compare how the video peer models—compared to a CDC social media vaccine graphic ad—prompted people to click on a link to find a vaccine near them via the CDC’s (which has English and Spanish versions).

Peer role models were Jesus Larralde from South Texas (English) and Rosa Herrera of Minnesota (Spanish).

rosa herrera peer modeling with psychological inoculation covid-19 vaccinesThe CDC ad showed a container of the COVID-19 vaccine. They featured a tagline of “When it’s your turn, get vaccinated,” in English and “Cuando sea tu turno, vacúnate,” in Spanish.

Ramirez and her team spent $2,000 in Facebook ads to promote the two peer models and two CDC ads.

Ads reached Facebook users in Medina County, Texas, and Atascosa County, Texas. Researchers chose these based on similar population size, high proportion of Spanish-speaking residents, and physical proximity to Bexar County.

“Both theory-based ads achieved lower cost per click to find a vaccine ($2.66 per click for Jesus in English and $3.14 per click for Rosa in Spanish), compared to the CDC generic ads ($4.03 in English and $5.43 in Spanish),” according to the study.

Peer models also fared better than CDC ads in the rate per 1,000 exposed Facebook users who clicked to find a vaccine.

  • For English ads, the rates were 14.9/1,000 for the CDC ad and 30.5/1,000 for the theory-based ad.
  • For Spanish ads, the rates were 31.5/1,000 for the CDC ad and 49.7/1,000 for the theory-based ad.

cdc span ad on covid-19 vaccines “Our peer model ads doubled the effects in English and yielded a 58% higher response rate in Spanish,” Ramirez said.

Ramirez hopes to conduct a larger-scale, more extensive study.

“These data demonstrate the potential to promote vaccine confidence with bilingual peer role model stories with psychological inoculation against misinformation,” she said.

What Can You Do to Reduce the Impact of COVID-19 among Latinos?

The need for vaccination among Latinos is critical, given the big toll COVID-19 is taking on Latinos.

The virus, since the start of the pandemic, has killed over 142,000 U.S. Latinos and hospitalized many more of our mothers, fathers, children, abuelos, and other family members.

This is happening is because COVID-19 is worsening inequities that had already existed. That makes it even harder for Latino communities to achieve good health, Ramirez said.

“Even before COVID, Latinos faced inequitable access to quality healthcare, health insurance, stable housing, reliable transportation, and healthy food, all while heavily exposed to environmental toxins, childhood trauma, and racial/ethnic discrimination,” she said. “These are the historic inequities that contribute to Latino health disparities in obesity, diabetes, certain cancers, and now COVID-19.”

rosa herrera covid-19 vaccinesStay informed by learning the facts about COVID-19 and the vaccine and avoiding vaccine misinformation.

Also, share these “Change of Heart” vaccine heroes in English or Spanish!

  • Rosa Herrera read on Facebook that the vaccine would inject her with a microchip. She learned that was a myth. See exactly what changed her heart and pushed her to get the vaccine! (en español)
  • Jesus Larralde was nervous about the vaccine’s possible side effects. His wife got the vaccine and was fine. See exactly what changed his heart and pushed him to get the vaccine! (en español)
  • Helen Cordova thought the vaccine was rushed. But she did her research. She learned the vaccine’s safety, and volunteered to be the first person in California to get the vaccine! See exactly what changed her heart! (en español)

Find COVID-19 vaccine locations near you in English or Spanish!


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