Does anticipation of a coming vaccine affect willingness to comply with prevention measures now?

2021 February 8

Since the beginning of the COVID-19 pandemic, officials have been trying to calibrate the right level of optimism to express in their public-health messaging. Will too much optimism lead people to think the crisis is over? Will too much pessimism cause people to decide that we just have to learn to live with the virus? Currently, officials may be wondering how news of the coming vaccine distribution affects the public's willingness to follow masking and distancing recommendations now. Does such news make people more likely or less likely to comply with such prevention measures? For public officials who want to encourage continued compliance until vaccines have been widely distributed, is it more effective to emphasize how soon a vaccine will be available or to emphasize that it will still take a long time for vaccines to be distributed to most people?

I had two competing theories:

  1. A vaccine coming soon makes people less worried about engaging in risky behaviors now because they think the coming vaccine will solve any future problems caused by their current risky behaviors.
  2. A vaccine coming soon makes people more willing to sacrifice their desire to engage in risky behaviors now because they won't need to make such sacrifices for very long. People are probably less willing to sacrifice if they must do so for a long time. For example, hypothetically, believing that a vaccine isn't coming until many years from now would probably make people unwilling to sacrifice their enjoyment and convenience now because they know they would be unwilling to modify their behaviors for that long.
These two competing theories suggest that the actual effect could go either way. Alternatively, these two competing effects could both occur simultaneously, cancelling each other and resulting in no observable effect.

I conducted a study to try to answer this question. At the beginning of February (2021) I surveyed a sample of several hundred U.S. users of Amazon Mechanical Turk (MTurk). I randomly assigned survey respondents to receive different messages about how long it will take for enough vaccines to be distributed to enable Americans to return to normal life. Some respondents were told four months, others twelve, and others were not given any estimate. I then asked respondents to tell me how likely they are to follow the CDC masking and distancing guidelines over the next 30 days and how likely they are to engage in each of a list of various risky behaviors over the next 30 days. For most of these outcome variables, I found no major differences between the three treatment groups. It appears that messages about the timing of the coming vaccines do not have much effect on the public's willingness to modify their behaviors to reduce the spread of the virus.

Self-reported likelihood of compliance with CDC recommendations

Estimated means: Self-reported likelihood of compliance with CDC recommendations

Self-reported likelihood of engaging in several risky behaviors

Sum of likelihoods of 9 risky behaviors

It is important to understand that an MTurk sample is not a random sample chosen from the population of the United States and is thus not likely to be representative of the country. It is possible that MTurk users, on average, may be more likely (or possibly less likely) to follow masking and distancing recommendations than the general U.S. population. The percentage of Americans who would say they are likely to follow the recommendations may thus be very different from the percentages shown in these graphs.

If the reader is simply interested in finding more general estimates of the percentage of Americans who are complying with masking and distancing recommendations, the reader should seek other published research for those numbers. Other surveys have been conducted with better samples to measure the level compliance in the US population (see, for example).

However, if the reader is more specifically interested in estimates of how vaccine-anticipation messaging affects compliance, my study provides the only such estimates of which I am aware. My data are not likely to provide an unbiased estimate of the level of compliance in the population, because the level of compliance among MTurk users may be different from the general population. However, if one assumes that vaccine-anticipation messaging has a similar effect on compliance among Mturk users as it does among the general population, these data may still be useful for the more specific purpose of my study.