Vaccinating a large enough portion of the population against various diseases is a constant challenge. Despite COVID-19 vaccination being offered for free, many people are still not fully vaccinated. In the study “Vaccination nudges: A study of pre-booked COVID-19 vaccinations in Sweden”, Niklas Johansson, Mats Ekman and Carl Bonander examines how pre-booked vaccinations have affected how many people get vaccinated.
There have been several attempts to increase the number of vaccinations, including requiring vaccination certificates in order to participate in certain events, mandatory vaccinations (where unvaccinated people are fined) or paying people to get vaccinated. Another way of increasing the number of vaccinations is to invite people to pre-booked vaccinations. During the COVID-19 vaccinations, Region Uppsala did exactly this, and sent out vaccination appointments to certain age groups. Other regions did not call on people in this manner.
- We have examined whether the appointments that were sent out to 16 and 17 year olds in Uppsala, says Niklas Jakobsson, professor of Economics at Karlstad Business School. Since the appointments were not sent out randomly, we used quasi-experimental methods in order to study the effect of these pre-booked vaccinations. In the study, we mainly used a synthetic control method where, instead of comparing the vaccination rate in Uppsala with the overall rate in other regions, you compare with regions most similar to Uppsala with regard to this age group in the period before the vaccinations.
- Uppsala was primarily compared to other regions with a similar vaccination for people aged 18-29 (who were not given pre-booked vaccination appointments), says Mats Ekman, lecturer in Economics at Karlstad Business School. Furthermore, the vaccination rate in the municipalities in Region Uppsala were compared to neighbouring municipalities in other regions. Our findings indicate that sending out pre-booked appointments in Region Uppsala increased the vaccination rate by approximately ten percentage points.
The intervention method used by Region Uppsala is called a “nudge”. Nudges are interesting from a social science perspective, as they do not affect anyone’s options. All youths in Region Uppsala who were given pre-booked vaccination appointments could, at no cost, choose not to go the appointment. They could also book their own appointments, just like youths in other regions. In terms of vaccinations, the only things that separate the youth in Region Uppsala from the youth in other Swedish regions is how the alternatives are presented.
- Even if we saw that Region Uppsala’s vaccination nudges had a significant effect (ten percentage points), you must be careful when drawing conclusions from our findings, says Niklas Jakobsson. Our findings are based on quasi-experimental methods, for one. There are also theoretical reasons to assume that a nudge has more impact when the choice is relatively insignificant to the individual.
Since young people very rarely become seriously ill from COVID-19, and since the side effects are trivial in most cases, the decision to get vaccinated or not is not as important to young people as to older people, who are significantly more at risk from SARS-CoV-2.
- When considering the effects on the population at large, our findings are therefore a bit on the high side, says Niklas Jakobsson. Even so, our findings should be of interest from a public health perspective, in the sense that a higher vaccination rate of a sterilising vaccine (meaning vaccinated individuals no longer infect others) will significantly decrease the spread of the diseases in question. We see a much bigger effect from this, compared to the effects from other kinds of interventions (vaccination certificates, payment, participating in a lottery, reminders) that have been studied using empirical research methods. When you consider that the other methods of increasing the vaccination rate often limits the freedom of choice of individuals, while also seeming to have relatively low effect on the number of vaccinations, the method used by Region Uppsala is interesting.
Niklas Jakobsson, Karlstad University, Mats Ekman, Karlstad University, and Carl Bonander, Gothenburg University, co-authored “A study of pre-booked COVID-19 vaccinations in Sweden”.
