439. Corowa-kun: Impact of a COVID-19 Vaccine Information Chatbot on Vaccine Hesitancy, Japan 2021

Abstract

Background Japan has one of the highest vaccine hesitancy rates in the world. According to a previous study, less than 30% of people strongly agreed that vaccines were safe, important, or effective. We created a COVID-19 vaccine information chatbot in a popular messenger app in Japan to answer COVID-19 vaccine frequently asked questions (FAQs) via text messages. We assessed the impact of chatbot text messages on COVID-19 vaccine hesitancy by conducting a cross-sectional survey among chatbot users. Methods LINE is the most popular messenger app in Japan; about 86 million people in Japan (roughly two-thirds of the population) use this messenger app. Corowa-kun, a free chatbot, was created in LINE on February 6, 2021. Corowa-kun provides instant, automated answers to frequently asked COVID-19 vaccine questions. A cross-sectional survey assessing COVID-19 vaccine hesitancy was conducted via Corowa-kun during April 5 to 12, 2021. We included persons ages 16 years old and older who had not received a COVID-19 vaccine. The survey was written in Japanese and consisted of 21 questions. Corowa-kun’s Consultation Room Corowa-kun is the mascot of an online chatbot. This chatbot in LINE is used to answer COVID-19 vaccine frequently asked questions (FAQs) via text messages. As of May 10th, 70 FAQs are available. Results A total of 59,676 persons used Corowa-kun during February to April 2021. The most commonly accessed message categories were: “I have (select comorbidity), can I get a COVID-19 vaccine?” (23%); followed by questions on adverse reactions (22%) and how the vaccine works (20%). 10,192 users (17%) participated in the survey. Median age was 55 years (range 16 to 97), and most were female (74%). Intention to receive a COVID-19 vaccine increased from 59% to 80% after using Corowa-kun (p < 0.01). Overall, 20% remained hesitant: 16% (1,675) were unsure, and 4% (364) did not intend to be vaccinated. Factors associated with vaccine hesitancy were: age 16 to 34 (odds ratio [OR] = 3.7, 95% confidential interval [CI]: 3.0–4.6, compared to age ≥65), female sex (OR = 2.4, Cl: 2.1–2.8), and history of another vaccine side-effect (OR = 2.5, Cl: 2.2–2.9). Being a physician (OR = 0.2, Cl: 0.1-0.4) and having received a flu vaccine the prior season (OR = 0.4, Cl: 0.3-0.4) were protective. COVID-19 vaccine acceptance increased and hesitancy decreased after using Corowa-kun, Japan, 2021 (n=10,192) *There was a statistically significant difference in responses between before and after using Corowa-kun (p < 0.01, Chi-square test). Univariable logistic regression models of factors associated with COVID-19 vaccine hesitancy, Japan, 2021 (n=10,192) Ref: reference NA: Logistic regression was not performed due to too small number (n≤3) Conclusion Corowa-kun reduced vaccine hesitancy by providing COVID-19 vaccine information in a messenger app. Mobile messenger apps could be leveraged to increase COVID-19 vaccine acceptance. Disclosures All Authors: No reported disclosures

The Effectiveness of Interventions for Increasing COVID-19 Vaccine Uptake: A Systematic Review

“…A cross-sectional study (pre-print) found that a chatbot implemented via the most popular messenger app in Japan increased vaccination intentions. However, this was a low quality study with no control group and pre- and post-vaccine intentions were measured after the intervention [ 41 ].…”

Effectiveness of chatbots on COVID vaccine confidence and acceptance in Thailand, Hong Kong, and Singapore

“…For COVID-19 vaccination, our study lends weight to previous findings that interactive conversations between chatbots and users can contribute to increased vaccine confidence, as seen in the Thailand child group 27,52 . Additionally, since our chatbots were hosted on two major mobile messenger apps, WhatsApp and Facebook Messenger, our study also adds weight to previous evidence supporting the potential of mobile messenger applications in delivering vaccination knowledge, debunking vaccine-related misinformation, and providing vaccination guidance to unvaccinated individuals 53,54 . Our data showed that a majority of chatbot users were less likely to decrease in vaccine confidence and acceptance, compared with non-users; however, our study also found some apparent evidence of 'backfire' effects, specifically among some chatbot using parents in Hong Kong where we observed decreased vaccine acceptance with chatbot use.…”

“…Since guardians can make direct or indirect vaccination decision on behalf of children and seniors, we tested the effectiveness of chatbot in increasing guardians' vaccine confidence and acceptance for their dependent family members. Taking an average of estimates from similar studies conducted in Japan and France 53,68 , we estimated an effect size of 15% and determined a sample size of 250 for each of the control and intervention group using power analysis. However, our sample sizes did not reach the target due to the surge in vaccine uptake at the time of participant recruitment following the emergence of Omicron and subsequent governmental vaccine mandates, school-based vaccine rollouts and increased risk perceptions of COVID-19 (Supplementary Fig.…”