Paper Title: Collateral damage from debunking mRNA vaccine misinformation

Author(s) and Year: Nicole M. Krause, Becca Beets, Emily L. Howell, Helen Tosteson, and Dietram A. Scheufelea (2023)

Journal: Vaccine (open access)

TL;DR: During the COVID‑19 pandemic, rapid corrective communication was used to counter vaccine misinformation, including the myth that mRNA vaccines contain live viruses. However, such corrections can unintentionally undermine trust in other vaccines, particularly vaccines containing live viruses. The study confirmed this hypothesis and showed that it is more pronounced among individuals with lower levels of vaccine acceptance. The study further proved that an additional damage control message, concerning misconceptions about live virus vaccines, mitigates these side effects without reducing the efficiency of the original message.

Why I chose this paper: Given the enormous impact the COVID-19 pandemic has had on everyone’s lives and having had a front-row seat to observe science communicators stand up, make mistakes, and improve during this high-pace crisis, was extremely interesting to me. Additionally, this type of research is crucial for improving communication and preventing repetition of the same mistakes in future crises.

Special note: This bite was prepared as part of a group project for the Science Communication and Outreach course at KU Leuven.

The Background

During the COVID-19 pandemic, strategic communication influencing public behavior played a crucial role in slowing the virus spread and reducing public health risks. However, due to the urgency of the crisis, the focus often shifted toward communicating quickly rather than communicating effectively. This issue became particularly pronounced in discussions about vaccine safety where misinformation spread rapidly. In response, organizations such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) released corrective messages to debunk widely circulating false claims. A prominent example is the myth that mRNA vaccines contain live viruses. In a complex, polarized crisis, even well‑intentioned corrective messages can sometimes lead to unintended, counterproductive effects.

Collateral damage hypothesis

Although corrections made by the WHO and the CDC might have reduced the myth that mRNA vaccines contain live viruses, they may unintentionally have encouraged distrust toward other vaccines that do use live viruses, by implicitly suggesting that these vaccines are less safe. The authors call this theory the collateral damage hypothesis. 

Two major risks are associated with this effect. First, as anti‑vaccination movements continue to grow in many countries, the likelihood of outbreaks of measles and other diseases preventable by live virus vaccines, such as poliovirus and monkeypox, increases. Second, in countries where access to mRNA vaccines for COVID-19 is limited, live virus vaccines are the primary resource of immunization. Efforts to correct misconceptions about mRNA vaccines might therefore involuntarily reduce the acceptance of these vaccines in those regions. 

The Research Question

In this study, the researchers attempted to answer the following questions regarding the WHO’s and CDC’s approach:

1. Will the corrective message that emphasizes the absence of live viruses in mRNA vaccines reduce the belief in this myth and will it additionally increase the distrust in other vaccines that do contain live viruses?
2. Will the collateral damage effect manifest more strongly among individuals with lower levels of vaccine acceptance?

Further, they aim to address the following question with the goal of improving future communication:

3. Will including a damage-control message – stating that live virus vaccines can be used safely – reduce negative beliefs about these vaccines compared to the original WHO and CDC message, and to what extent might it backfire among individuals with low vaccine acceptance?

The Methods

To answer these research questions, 430 people forming a representative sample of the US population were equally divided into three groups:

1. The first group receives a corrective message with high resemblance to the existing WHO website. It explains the new vaccine technology ‘mRNA’, and debunks the myth that mRNA vaccines contain live viruses;
2. The second group receives a damage control message containing additional clarification on live virus vaccines in the form of ‘But in other vaccines, live viruses are used safely’; and
3. A control group receives no corrective message. The text describes mRNA technology, without debunking statements. 

After having observed these messages, the respondents evaluated four different variables: belief in the statement that mRNA vaccines contain live viruses, the societal and personal risks of live virus vaccines, and individual opposition to live virus vaccines. The authors then investigated the same statements, now taking the vaccine acceptance levels of the test population into account.

The Results

Original WHO message

The first result is that both the original corrective message and the damage control version successfully reduced belief in the myth that mRNA vaccines contain live viruses. However, the original corrective message also produced collateral damage. Participants exposed to it perceived higher societal risks associated with live virus vaccines. Remarkably, the increase in perceived societal risk did not translate into an increase in personal resistance to vaccination, which might be explained by the fact that individuals are not obliged to receive these vaccines. 

The researchers found no differences between the acceptance-level groups in their belief in the live viruses myth. However, the hypothesis that collateral damage is more pronounced among individuals with existing negative attitudes towards vaccines, is supported. Specifically, the original corrective message strengthened risk perception related to vaccines for the group with low vaccine acceptance, whereas this effect was not observed in those with medium or high levels of vaccine acceptance.

Damage control or backfiring?

Regardless of initial vaccine acceptance, the damage control message effectively mitigated the collateral damage, while still reducing the belief in the false statement. Although a definitive answer to whether the damage control message backfires among individuals with low vaccine acceptance could not be given, the results indicate that such backlash is unlikely. However, given that the original sample group was not based on acceptance level, a smaller number of low-vaccine-acceptant respondents participated in the study, making it harder to obtain significant results.

The Impact 

The collateral damage effect identified in this study is highly relevant beyond the specific case of mRNA vaccines and may extend to other areas of health and science communication. When corrective messages focus solely on disproving false claims, without considering their broader context, the likelihood of collateral damage increases substantially. Therefore, the researchers argue that correction initiatives for misinformation should routinely investigate potential unintended effects, including shifts in beliefs that are not directly targeted by the correction itself.

In conclusion, although this study focused on the communication about (mRNA) vaccine acceptability, it shows that broader research about the unintended harms of corrective communication is crucial beyond the end of the COVID‑19 crisis.

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Alt text for featured image: Cardboard sign held during a protest march, saying ‘Unvaxxed control group team leader’.

Written by Elien Van Clemen

Edited by Chao ‘George’ Gao and Mykyta ‘Nik’ Kliapets

Featured image credit: Ivan Radic under CC BY 2.0