How to inform, persuade and remind about COVID-19 vaccination

Pedro Rey
 

@varelalaf

After a year in which the fight to control the transmission of COVID-19 has set the agenda, the debate is now focused on how to get a sufficient percentage of the population vaccinated to achieve the so-called "group immunity" as soon as possible. The objective now goes to the supply side: it is about establishing the sequence in which different population groups should be vaccinated (and with which vaccine each one) and making sure that the prioritization is fulfilled. We must also resolve as soon as possible how to eliminate bureaucratic obstacles so that vaccines are more easily accessible, more operational from a logistical point of view and can be purchased by the states at a reasonable price. However, solving the supply problem will be futile if we fail to stimulate demand so that the effective vaccination rate is as high as possible. For this, it is essential to understand both how the potential vaccination subjects behave ‒guided by their beliefs, their perceptions about safety and risk and by their cognitive biases‒ and in what way we can influence that behaviour to guide them towards the socially desirable direction that allows the reduction of disease incidence. 

Below I list a series of suggestions for solving the three fundamental problems related to the demand for a COVID-19 vaccine: information, persuasion and the need to remind individuals to complete their vaccination, especially with vaccines that require two doses spaced apart in time. These three problems are in turn related to three different population groups: those who oppose vaccines, those who are reluctant against vaccines, and those who, even predisposed to get vaccinated, may end up not completing their vaccination.

1. How to inform about vaccines and neutralize false myths

Spain is one of the European countries where the percentage of the population that sympathizes with the anti-vaccine movement is lower. It's estimated, however, that this percentage has grown in recent years to around 6%. Fortunately, we are not close to the figures for countries like France (40% anti-vaccine sympathizers), nor is the debate as politicized as in the United States, where the percentage of the population willing to be vaccinated fell from 70% in April 2020 to close to 50% on dates close to the last elections. However, the percentage of the Spanish population that shows doubts about a COVID-19 vaccine is currently close to 30%, according to recent surveys, so even if we get all those who intend to get vaccinated to do so, the margin of error to achieve group immunity (which is estimated to require between 60% and 80% of the population vaccinated) would be small enough that the strategy should focus on ensuring that no one who has doubts about a vaccine joins the group of those who strongly oppose them. Let us, therefore, forget about convincing those that we are not going to convince and do not contribute to spreading their false messages against vaccines by discussing their arguments and let's focus on those who still have doubts but can still be persuaded. It is not a matter of vilifying the anti-vaxxers or treating them as ignorant, but of being practical and avoiding entering into a sterile discussion that will not convince them, instead it would constitute a loudspeaker for the dissemination of their message among those who are still in doubt. So we won't, but if you want a good summary of objective arguments to refute anti-vaccine, you can find it here. 

Let's focus on the doubters. Even among the 92% of the population who believe that vaccines are safe and effective, at least a third express legitimate concerns about their possible side effects, the possible pressure that the pharmaceutical industry has exerted to promote mandatory vaccination or even the speed with which, in the case of COVID-19, vaccines have been developed.

One way to reduce such concerns is to confront doubters with the cognitive biases that may be causing their concern. Our brain is lousy at processing complex information about very low probability risks, such as an adverse reaction produced by a vaccine. Mention that for this reason, we human beings resort to psychological biases such as the "confirmation bias", that is, the tendency to accept only the information that matches our a priori beliefs; the "illusion bias", by which we believe that we know more about a phenomenon than we know, or the "causality bias", by which we attribute a cause-effect relationship to phenomena that occur in the same period. Time, such as vaccination and detection of autism symptoms in childhood, for example, when there is no relationship between them, can be difficult but very useful. Another good tactic would be to expose the persuasive tricks that anti-vaccines use to spread their message: require 100% certainty that there are no side effects - when no drug offers absolute certainty that it has no side effects - select studies that partially support your message without mention the enormous abundance of studies that refute him or indicate the limitations of the study on which they are based, and omit the broad consensus that exists against his ideas. 

2. How to persuade doubters about vaccines

These days, perhaps the most effective measure to convince those who have doubts about vaccines, that we have observed, has been the spread of information about politicians who "have skipped the line" to get vaccinated. Social outrage at these cases also implies that getting vaccinated is interpreted not as an obligation but as a privilege that we should all have access to.

In addition to this anecdotal evidence, it is important to recognise that information is not the same as persuasion. When in doubt, the statistical data on effectiveness and safety are scarcely attractive and have little power of conviction. On the other hand, persuasion requires combining rigorous information with an emotional narrative that hits home. Talking about cases of people who have died or have suffered the consequences of the disease due to not having been vaccinated on time can be much more effective, given that people tend to empathize more with real and upcoming stories than with cold statistics. 

Listening to the reluctance of those who do not want to be vaccinated and moulding the pro arguments to that reluctance, without judging them, can also be very effective.

3. How to get individuals to complete their vaccination

Faced with a crisis like the current one, we are eager to feel we are contributing to the solution. For this, we need clear rules on what is the correct behaviour that we must follow. Think, for example, of the initial doubts that many citizens had a year ago about whether or not they should wear masks, caused in part because the authorities, faced with the initial shortage of masks, did not send a clear message about their effectiveness. Fortunately, we’ve managed to enforce the social norm of wearing a mask and even stigmatize those who do not wear it. We must take advantage of these same teachings in the case of vaccination: emphasize the public good component and the externality ("I don't get vaccinated for myself, I do it for you and your family") that a vaccine provides. We must make people proud that they have been vaccinated can even brag about it. Think, for example, of the stickers you see on cars in the United States indicating that they have voted… Why not stickers and T-shirts that say “I have been vaccinated”?

You can even go one step further and create vaccination certificates. There is debate about the possible negative effects that imposing vaccination certificates can have to travel or when wishing to access certain privileges. On the one hand, the obligation to vaccinate could send the contradictory message that “they make it mandatory because otherwise people would not be vaccinated”, which can reinforce all the doubts about the vaccine. On the other hand, the obligation to be vaccinated to carry out certain activities could have a greater positive effect.

Perhaps a middle way is to consider the power of the "default option": de facto, citizens would be allocated a specific appointment to be vaccinated, to which they should appear unless they could claim a reason to the contrary. It has been observed that the mere existence of a minimum inexpensive procedure for not complying with the option established by default can be very effective in getting people to comply with the desired behaviour.

Finally, since most of the vaccines developed so far will require a second dose, vaccine doses mustn't be wasted with first vaccinations that are not completed later. For this, it will be essential to create logistics in which the date of the second vaccination is imposed from the moment of the first vaccination and to establish an effective reminder system. Reducing the difficulties of getting vaccinated, and turning the process into a simple and quick one, will also be important.

I hope I have convinced you that by using what we know about human behaviour, we can all contribute to reducing problems from the demand side of much-needed vaccination. Solving supply problems is fundamentally in the hands of the health authorities.