Coronavirus (COVID-19) vaccines have saved millions of lives since release and remain akey tool in the fight against the pandemic.However, most countries have not reached the vaccine uptake rates needed to relievepressure on hospitals and intensive care units (ICUs) during peak corona periods. Reducedeffectiveness of vaccines in preventing infections with the Omicron variant and mildercourses of the disease may trigger and support beliefs that vaccination is no longernecessary, especially among vaccine sceptics.The term 'vaccine sceptic', however, is usedheterogeneously and often interchangeably to describe both 'vaccine hesitants' and'vaccine deniers'. In contrast to vaccine deniers, characterized by a definite andunwavering decision not to get vaccinated, vaccine hesitants are characterized by aspectrum of indecisiveness, with a high need for information on both benefits and harms.They may still decide to get vaccinated if information succeeds in convincing them. Inlight of the potential for a change of mind in vaccine-hesitants the key question is: Howdoes one best address their high needs for balanced risk ratio information? Evidence fromcognitive and behavioral science suggests that interactive simulations of riskinformation, which imitate mechanisms by which humans sequentially and experientiallysample risk information naturally, can be more effective in helping people developadequate risk perceptions and initiate behavioral change than the ubiquitously usedconventional text-based formats. The study therefore seeks to determine if interactiverisk ratio simulation relative to a text-based format are more effective in promptingpositive change in unvaccinated, vaccine-hesitant respondents' intention to get theCOVID-19 and also in the respective benefit-to-harm ratio assessment during the Omicronwave in Germany.
The iWILL study is a cross sectional study that aims to evaluate the effectiveness of
interactive risk ratio simulation (intervention) relative to a text-based format
(control) in COVID-19 vaccine-hesitant people in Germany.
The objectives of iWILL are:
1. to adapt the already piloted, digital, interactive, evidence-based counseling tool
ExploreVac (focus on herd protection) as well as a new simulation (focus on
individual protection) to the most current evidence (including age adjustment) for
communicating vaccine effectiveness and side effects as evidence-based patient
information using the example of COVID-19 vaccination,
2. to implement the adapted version of ExploreVac and the new simulation in care with
the aim to increase the vaccination incidence among vaccine hesitant individuals, to
improve their subjective assessment of vaccination's benefits and harms, and to
reduce the presumed increased counseling effort of the GP compared to standard care,
3. to test whether the intervention is superior as compared to the control on these
endpoints,
4. to draw conclusions about the transferability of the developed method for other
established vaccinations (HPV, influenza protection) and vaccinations for future
infectious diseases.
Primary hypothesis:
(H1) The intervention group (interactive simulations) will show a higher positive change
(T0/baseline to T1/after intervention) in vaccination intention than the control group
(text-based information).
Secondary hypotheses:
(H2) The intervention group (interactive simulations) will show a higher positive change
(T0/baseline to T1/after intervention) in their positive subjective benefit-to-harm
assessment of the COVID-19 vaccine's benefit-to-harm ratio than does the control group.
(H3) The intervention group reports a lower need for additional counseling by their GPs
than does the control group.
(H4) The intervention group (interactive simulations) will show a higher correspondence
between their intended behavior (T1) and their actual reported vacccinataion behavior
(T2/ follow-up after 6 months).
Recruitment of unvaccinated, vaccine hesitant German residents will be established by
using probability-based internet panels maintained by respondi (Cologne, Germany). The
study will be pursued with cross-sectional national sample.
Intervention condition: two interactive simulations informing 1) about absolute risks of
infection, hospitalization, ICU admission, and death after exposure to COVID-19 relative
to vaccination's side effects (e.g., myocarditis in men ≤35 years) in 100,000 vaccinated
and 100,000 unvaccinated individuals, all adjustable to four different age groups (18- 34
years, 35-59 years, 60-79 years, ≥ 80 years due to considerable differences in each of
the depicted risks (Supplement) and 2) about the benefits of vaccination for the
population as a whole (herd) in terms of preventing infections and deaths.
Control condition (see also below): two text module informing 1) about absolute risks of
infection, hospitalization, ICU admission, and death after exposure to COVID-19 relative
to vaccination's side effects (e.g., myocarditis in men ≤35 years) in 100,000 vaccinated
and 100,000 unvaccinated individuals, all adjustable to four different age groups (18- 34
years, 35-59 years, 60-79 years, ≥ 80 years due to considerable differences in each of
the depicted risks (Supplement) and 2) about the benefits of vaccination for the
population as a whole (herd) in terms of preventing infections and deaths.
The educative information material in both conditions is based on non-directive
evidence-based patient counseling according to the guideline on evidence-based health
information. After the study condition, participants are informed that any further
questions about vaccination can be discussed with the GP.
The questionnaire at T0 (baseline) and T1 (directly after the intervention) takes maximum
10 minutes to complete (without exploration of intervention material). Given that
participants are free to spend as much time as participants want with the educative
information material, the total survey time can be longer, however.
About six months after first participation in the study, participants are re-contacted
via e-mail and are asked to fill out a second questionnaire (6-months follow-up, T2),
which approximately takes about 5 minutes to complete to learn more about potential the
translation of the intention into vaccination behavior.
Behavioral: Simulation
The participants in the intervention group receive two interactive simulations in
addition to a general text module that provides sequential, animated information on the
spread of the virus without prevention, the effectiveness of vaccination and potential
side effects of vaccination on a herd protection level and the individual level.
Behavioral: Text
The participants in the control group receive two text-based information in addition to a
general text module that provides information on the spread of the virus without
prevention, the effectiveness of vaccination and potential side effects of vaccination on
a herd protection level and the individual level.
Both conditions ensure the provision of a level of knowledge that at least corresponds to
standard care.
Inclusion Criteria:
- Hesitancy towards COVID-19 vaccination
- Not yet vaccinated against COVID-19
- Age ≥ 18 years.
Exclusion Criteria:
- No hesitancy towards COVID-19 vaccination
- Already vaccinated
- Age < 18 years.
Charité - Universitätsmedizin Berlin
Berlin, Germany
Investigator: Odette Wegwarth, Prof. Dr.
Contact: +49(0) 30 450 - 531 074
odette.wegwarth@charite.de
Investigator: Odette Wegwarth, Prof. Dr.
Odette Wegwarth, Prof. Dr.
+49(0) 30 450 531 074
odette.wegwarth@charite.de
Clara O Schirren, MA
+49(0) 30 450 - 531 056
clara.schirren@charite.de
Odette Wegwarth, Prof. Dr., Principal Investigator
Charite University, Berlin, Germany