The role of nudges, carrots and sticks in reaching target rates for Covid vaccinations

After everyone who wants to be vaccinated against Covid-19 has had their shots, what percentage of the population is likely to remain unvaccinated – and what should governments do about it?

Two articles bring carrots, sticks, behavioral economics and nudge theory into policy-shaping considerations.

Mind you, in this country it could be a while before the government has to think about persuading reluctant or complacent citizens to take their Covid shots.

Judith Sloan, an economist and company director, in an article for The Australian references Richard Thaler, who was awarded the Nobel memorial prize in economic sciences in 2017.

Thaler, who made his name by combining the disciplines of economics and psychology, is famous for nudge theory, which he discussed in an interview published in The New York Times this month:

 “Nudges gently guide people without requirements or economic incentives. Informing people about the benefits of vaccinations and making it as easy as possible to get a shot are in this category.”

Earlier in the Covid vaccine campaign, he said, nudges were the appropriate policy tool because the initial doses mostly went to those who wanted the shots.

But at this point in the US (alas, not in New Zealand), the people who remain unvaccinated but would benefit from shots largely range from sceptics to anti-vaxxers.

“That’s why it’s time to go well beyond nudging.”

Judith Sloan notes there is influential support for this approach in Australia.

Labor leader Anthony Albanese has raised the idea of giving $300 to everyone who is fully vaccinated by the end of the year.  This is an expensive option: it would cost almost $6bn.

The Grattan Institute has proposed a national lottery giving away ten $1 million prizes a week for eight weeks from Melbourne Cup Day to Christmas.

Another option is simply providing easy access to a preferred vaccine free of charge.

The proportion of the adult population that is fully vaccinated in Australia is just above one-quarter.

In this country, just over 1 million people have been fully vaccinated – 21.4% of the population.

Both countries are far behind other countries at this stage, including Canada, Britain, Israel, Iceland, Chile and several EU countries.

Parts of the US have high rates of vaccination but others have low rates, Sloan notes.

By her reckoning, Australia can’t expect to get 70-80 per cent of the adult population fully vaccinated before the end of the year.

What we don’t know at this stage is how difficult it will be to get harder-to-convince individuals to get the jab because we are still at the stage where it has been logistically difficult for many people – those under 40 especially – to get a shot, particularly the shot of their choice.

This issue of vaccine variety has played very badly for Australia. The lack of confidence in the AstraZeneca vaccine shows up in the figures. This has been caused by the small number of adverse reactions, including deaths, the equivocating advice of the Australian Technical Advisory Group on Immunisation and the refusal of Queensland’s chief health officer to recommend the vaccine for younger people.

The latest Newspoll results indicated that only 7 per cent of respondents were fine with getting AZ or Pfizer compared with 33 per cent who were fine with getting vaccinated but would wait for Pfizer.

Given this specific form of hesitancy, we don’t know when there will be sufficient supplies of their preferred vaccine (Moderna also may be acceptable) to increase the overall vaccination rates to the minimum acceptable percentages. Quite a lot is being made of younger people being prepared to get an AZ shot, but the uptake is still relatively low.

 So let’s fast-forward to where everyone who is eligible to get a shot, preferably the shot of their choice, has been able to do so. What percentage of the population is likely to remain unvac­cinated and what should govern­ments do to promote the unvac­cinated to change their minds?

There are several estimates of the proportion of the population who ultimately will not get vaccinated.  Sloan references a Newspoll survey which suggests a figure of 11 per cent while estimates offered by the University of Melbourne based on surveys put the proportion between 10 and 20 per cent, with younger members of the population more likely to be hesitant.

Acknowledging that some will never agree, Sloan says there are two choices for getting the last of the unvaccinated over the line – the carrot and the stick.

The carrot can include simple cash payments, entry to a lottery, transport and food vouchers (all of these measures have been used overseas).

The stick involves imposing costs on the unvaccinated not borne by those who have had the jab.

It can include the use of vaccine passports to control entry to certain places and the use of some transport. We are seeing this development overseas, but it carries high political risks and may have the perverse effect of causing the hesitant to become strongly anti-vaccination. There is also an issue of the integrity of the passport itself.

Employers demanding workers be vaccinated is also a process fraught with complications, in part because of the legal uncertainties surrounding such mandates. To be sure, the requirement for workers to be vaccinated in some settings is clearly defensible and generally has legal backing, but there is a wide range of ambiguous situations that will mean rapid progress on this front is unlikely.

The bottom line is that there is no easy way to induce very high rates of vaccination, in part because the benefits do not simply accrue to jabbed individuals and their loved ones but also to the community at large. There is also a distinct possibility that some of the measures may have perverse effects on the hesitant.

 It’s also important at this stage not to oversell what will occur when vaccination rates rise to the target levels.

But Sloan’s concluding observation is somewhat sobering:

Judged by the experience of several countries that are well ahead of us on the curve, it’s no panacea even if rates of hospitalisation and deaths are lower. Significant numbers of positive cases are still likely to be recorded.

Meg Elkins, Robert Hoffmann and Swee-Hoon Chuah discuss carrots and sticks, too, in an article published by The Conversation:

Money, doughnuts and beer. As high-tech and effective as our COVID vaccines are, getting enough people to take them to achieve herd immunity may come down to some very Homer Simpson-esque tools of persuasion.

Across the US, governments and private organisations are trying out carrots to lift flagging vaccination rates.

California, for example, has tried a US$116 million incentive program offering US$50 gift cards for every first vaccination and 10 prizes of US$1.5 million. On the other side of the country, New Yorkers have been offered US$100 as well as inducements such as the chance win a full university scholarship.

It’s a smörgåsbord for behavioural researchers to pick over, with lessons for nations such as Australia, which is now at the point of discussing incentive options.

But data from the Melbourne Institute shows cash incentives of up $100 would only marginally increase vaccination rates and the researchers aren’t confident $300 will make that much difference.

Economic research in the past has strongly endorsed lotteries as an incentive, but questions are raised about their effectiveness with COVID vaccination rates.

An analysis of Ohio’s vaccination lottery, for example, found no evidence it was associated with increased rates of adult COVID-19 vaccinations.

While the researchers — from the Boston University School of Medicine — concede their study may be “underpowered”, they do make a strong point that more evidence is needed to support the “widespread and potentially costly adoption” of such incentives.

According to Joshua Liao, head of the Value & Systems Science Lab at the University of Washington:

Financial incentives can be pragmatic and effective, and good design may help reduce the potential problems with cash prizes. But we should be careful not to confuse short-term effectiveness (more vaccination now) with longer-term goals (greater engagement in vaccination into the future).

This warning would seem to apply doubly to vaccination inducements such as free doughnuts and free beer.

The Convsersation article says this seems the right time to turn to the four principles identified by the UK’s Behavioural Insights Team for shifting behaviour through “nudges”.

A nudge works differently to an incentive. In the words of nudge theory’s great popularisers, Richard Thaler and Cass Sunstein, a nudge is:

any aspect of the choice architecture that alters people’s behaviour in a predictable way without forbidding any options or significantly changing their economic incentives. To count as a mere nudge, the intervention must be easy and cheap to avoid. Nudges are not mandates. Putting fruit at eye level counts as a nudge. Banning junk food does not.“

The Behavioural Insights Team’s four principles, known the EAST framework, are fairly straightforward.

Make it easy. A common way to make a behaviour easy is to make it the default. Organ donor schemes that require opting out, for example, have dramatically higher participation rate than those requiring donors to opt in.

Make it attractive. An example is painting flies on urinals to improve males’ aim and reduce cleaning costs.

Make is social. An example is the nudge hotels give you to reuse your towels, with a message along the lines of: “Most other guests staying at this hotel reuse towels.”

Make it timely. This involves prompting people when they are most receptive — such as when moving house to consider change their energy account, or at the beginning of the new year to join a gym.

So far, so good – but how should these principles be applied to the COVID vaccines?

The Conversation answers:

One possibility is demonstrated by a large experiment (involving more than 47,000 participants) showing simple messages could nudge people to get an influenza shot.

At the cost of two text messages to patients prior to their next doctor’s appointment, researchers found one message theme — letting the patient know a flu shot was “reserved” for them — increased vaccinations by 11% .

These type of personalised approaches won’t necessarily translate to COVID, of course. If someone believes a COVID vaccine is an experimental gene therapy that might change their DNA and render them sterile, there’s probably nothing that can be done to change their opposition.

But key to all nudges is recognising context matters. As the Behavioural Insights Team notes: “Something that works well in one area of policy might not work quite so well in another.”

We need more personalised approaches. Too much of our discussion about vaccine hesitancy has been imagining the problem in rational terms. But perceptions about COVID-19 and vaccines are driven by emotion, not reason. The more we factor that emotion in, the better our responses will be.

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