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A patient receiving a Covid vaccination

A new study from NDPH suggests that cash incentives – but not lotteries – could help persuade people unvaccinated against COVID-19 to get their jab. The results have been published on medRxiv.  

Evidence suggests that achieving herd immunity to the coronavirus will require 75-90% of populations to be vaccinated. However, many countries remain far from this goal, even if they have sufficient vaccine supplies. Potentially this could hinder a return to ‘normal life’ due to ongoing transmission of the coronavirus.

Some governments are considering, or have already implemented, policies to encourage vaccine uptake by restricting personal freedoms. In France, for instance, from the beginning of August people have been required by law to have a ‘COVID-19 health pass’ to access many public venues, including restaurants, museums, swimming pools and trains. Such measures, however, are controversial and can lead to protests and unrest.

An alternative approach is to offer incentives to be vaccinated such as cash and cash equivalents, or entering people into lotteries for high-value prizes. Until now, there has been little evidence on whether these are actually effective in persuading people to book an appointment.

To investigate this, researchers from NDPH’s Health Economics Research Centre conducted an online study on over 1,600 unvaccinated US citizens. They were randomly allocated to watch one of three 45-second informational videos promoting COVID-19 vaccination.

  • Video one (the control) explained the health benefits of receiving a COVID-19 vaccination.
  • Video two was identical to the control video but informed viewers at the end that they could be entered into a lottery to win over 1 million dollars if they were vaccinated.
  • Video three was identical to the control video but informed viewers that they could receive up to $100 cash/cash equivalent if they were vaccinated.

After viewing the assigned video, participants could either end the survey or click through to a webpage with information about where they could get a COVID-19 vaccination locally.

Key results

Compared with the control video, offering individuals a cash/cash equivalent incentive increased the proportion who expressed interest in being vaccinated from 16 to 22%.

This means that the odds of participants expressing an interest in vaccination was 1.5 times greater when offered cash/a cash equivalent.

In contrast, the proportion of individuals who expressed interest in being vaccinated was slightly lower for those assigned to the video with the lottery incentive, at 14%.

These results are supported by evidence from other surveys in the USA and Germany which found that people would be more willing to get vaccinated if offered a monetary incentive. However, the researchers say that a range of factors affect vaccine uptake, including convenience of accessing a vaccination centre, and the personal freedoms that proof of vaccination would allow.

Professor Philip Clarke, Director of the Health Economics Research Centre, and lead author of the study said: ‘Our experiment simulates real-world decision-making situations in which videos play an increasingly important role in delivering information related to public policy. The results suggest that incentives to be vaccinated can be effective, but that the type of incentive matters – at least in the US, cash is effective while lotteries are not. Further targeted research to find out what incentives and other policies work best should pay real dividends.’