Dr. Joshua Liao discusses how psychological biases can allow worries about vaccine side effects to overwhelm rational consideration.
Millions of Americans have received Covid-19 vaccines. Over 10% of individuals in many states have received a single dose, and the U.S. is on track to provide enough vaccines to cover all adults across the country by the end of July. These are encouraging events as public officials work to vaccinate most adults across the country.
But the United States will not be able to take full advantage of the benefits of vaccines if not enough citizens take them. Unfortunately, there are reasons for concern about this dynamic, and recent surveys suggest that 30% to 40% of Americans “likely” or “definitely” will not receive the Covid-19 vaccine.
One of the main reasons for this is the fear of side effects. Among people who would refuse vaccination, nearly two-thirds cited concerns about side effects. My own experience confirms this: over the last few months, I have had loved ones and colleagues from all over the country expressing fears about the vaccine.
It is important to avoid cognitive biases about Covid-19 vaccines, and even more about potential side effects given the widespread public concern. Americans can take two steps to avoid cognitive errors when considering the side effects of Covid-19.
Recognize your point of comparison
The basic insight of behavioral science is that human perception can be influenced by “reference points.” Previous experiences of individuals with a brand or product can serve as references to determine their satisfaction with it (how do current and previous experiences compare?).
People can judge professional change – new job or boss – based on current circumstances (how does that compare to the status quo?), Expected circumstances (how does it compare to the changes I expected?) Or other circumstances (how can this be compared to situations of others?). Behavioral scientists call this phenomenon reference dependence: the tendency to consider gains and losses in relation to a particular reference point.
Americans can take a few steps to ensure they clearly think about the side effects of the vaccine.
This insight is extremely relevant for decisions about Covid-19 vaccines. Younger people without chronic diseases can compare vaccination with their status quo of good health, reference points that may make vaccination seem a risky choice with a low reward (why would I risk the side effects for good health I have now?).
Unfortunately, the pandemic remains active worldwide, new variants are emerging and America is reaching almost 250,000 daily cases recently in January. Therefore, for many people, a better reference point for the side effects of the vaccine could be the effects of contracting Covid-19 itself.
The side effects of vaccination may seem great compared to perfect health or the expectation of continued good health. They differ in relation to the risk of hospitalization, ventilation, long-term complications or death from the virus.
Think about how the risk is framed
Another principle of behavioral science is that people tend to make decisions using a framework within which choices are presented. These framing effects have been reported in many different settings, including health care.
For example, framing can affect patients ’willingness to accept treatments — for example, whether a surgical procedure is framed positively (e.g., 80% success) or negatively (e.g., 20% failure). In previous work, I have shown that physician support for policies that punish inappropriate treatments can be influenced by the way treatment harm is shaped.
The insight into Covid-19 vaccination is that Americans’ willingness to accept the risks of side effects may depend on how they are set – the difference between a 1% chance of a side effect versus a 99% chance of avoiding it. It is important that the framing can also be updated as we gain more experience with vaccination: a 99% chance of avoiding side effects would be stronger if it reflects the experiences of millions rather than thousands.
There are certainly no silver bullets or unambiguous solutions to address vaccine fears. As I have already noted, cognitive errors can also intersect both directions: people predisposed to believe in vaccines must also protect themselves from the tendency to overlook new information about side effects and other harm. We all need to watch out for faulty reference points, framing, and dead spots as we continue to learn more about Covid-19.
Regardless, Americans can take a few steps to ensure they clearly think about the side effects of the vaccine. This is a crucial part of achieving the potential of the Covid-19 vaccine as a tool to overcome the pandemic.
Disclosure: Joshua Liao reports a stock investment in Johnson & Johnson, which owns Janssen Biotech, Inc., the maker of the Covid-19 vaccine.
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