Randomised controlled trials of behavioural nudges delivered through text messages to increase influenza and COVID-19 vaccine uptake among pregnant women (EPIC study) in Australia.

BACKGROUND

Influenza and COVID-19 vaccine uptake among pregnant women is sub-optimal. We assessed the effectiveness of a multi-component behavioural nudge intervention to improve COVID-19 and influenza vaccine uptake among pregnant women.

METHODS

A 'nudge' was developed that comprised three SMS text message reminders with a social norming message, links to vaccine safety information, videos of health professionals and consumers recommending vaccination in pregnancy and a pledge to get vaccinated. In separate RCTs, pregnant women who had not received an influenza vaccine during the 2023 influenza season, or received ≤2 doses of a COVID-19 vaccine, were randomised (1:1) to standard care or intervention at four hospitals in Australia.

RESULTS

A total of 1090 and 1068 pregnant women were randomised to the COVID-19 and influenza RCTs, respectively. The nudges resulted in a 1.6 % increase in COVID-19 vaccine uptake and 1.7 % increase in influenza vaccine uptake among pregnant women. However, there was no significant difference in the percentage of pregnant women in the intervention (2.7 %) and the standard care (1.1 %) groups receiving one dose of a COVID-19 vaccine from randomisation until delivery (odds ratio, 2.40; 95 % confidence interval [CI], 0.91 to 6.30, P = 0.08). Similarly, there was no significant difference in the percentage of pregnant women in the intervention (58.0 %) and the standard care (56.3 %) groups receiving the influenza vaccine from the time of randomisation until delivery (odds ratio, 1.07; 95 % CI, 0.84 to 1.38, P = 0.58). Less than 2 % of women had viewed the video content of the nudges in both RCTs.

CONCLUSIONS

The nudges delivered via SMS resulted in small increases in COVID-19 and influenza vaccination uptake among pregnant women. Considering the very low cost of bulk SMS, these nudges may be cost-effective interventions at a population level.