An interventional study of Google ads in Vaccine-Preventable Diseases and Vaccine Refusal, sponsored by The University of Hong Kong. Completed at 1 site in Hong Kong. Per ClinicalTrials.gov, last updated 2022-08-16.
Sponsored by The University of Hong Kong · Not applicable, Interventional, and Health services research
The success of vaccination programs often depends on the effectiveness of the vaccine messages, particularly during emergencies such as the COVID-19 pandemic. The current suboptimal uptake of COVID-19 vaccines across many parts of the world highlights the tremendous challenges in overcoming vaccine hesitancy and refusal even in the context of a world-devastating pandemic. The investigators conducted a randomized controlled trial in Hong Kong to evaluate the impact of seven vaccine messages on COVID-19 vaccine uptake (with the government slogan as the control). The participants included 127,000 individuals who googled COVID-19-related information during July-October 2021.
This study aims to evaluate the effectiveness of using the Google advertising platforms on influencing the uptake of COVID-19 vaccines in Hong Kong. When completed, the rich database compiled through this proposed study will provide increased insight into vaccine hesitancy in Hong Kong. Insights from the optimised online advertising trial can aid in providing crucial technical and theoretical support to the relevant health authorities for any potential evidence-based policy intervention in addressing vaccine hesitancy issues or the public's concerns towards vaccines in Hong Kong.
54 studies on the registry are indexed under Vaccine-Preventable Diseases; 14 are open to participants now.
This study's enrollment of 127,000 is above the median of 180 across 41 interventional studies indexed under Vaccine-Preventable Diseases.
Browse Vaccine-Preventable Diseases studies →The University of Hong Kong is the lead sponsor of 1,286 studies on the registry; 343 are open to participants now.
Of its 9 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Participants were shown with the government slogan for the COVID-19 vaccine campaign in 2021. This was the control arm.
Behavioral: Google ads
The ad emphasized that vaccine uptake in Hong Kong substantially lagged behind that in comparable populations such as Singapore and the UK.
Behavioral: Google ads
The ad emphasized that vaccinated people could be exempted from some disruptive control measures such as mandatory testing
Behavioral: Google ads
The ad prompted people to get vaccinated in order to protect their family.
Behavioral: Google ads
The ad prompted people to get vaccinated in order to be eligible for the numerous COVID-19 lotteries in Hong Kong
Behavioral: Google ads
The ad emphasized that COVID-19 has caused millions of deaths worldwide.
Behavioral: Google ads
The ad prompted people to get vaccinated to help Hong Kong reopen sooner.
Behavioral: Google ads
Individuals who googled COVID-19 information in Hong Kong were randomized to see one of the seven ads and, if they clicked on the ads, the corresponding vaccine message on our website
Number of bookings following each message delivery within 6 hours
The number of bookings made within X = 6 hours following each message delivery
Time frame: 6 hours
Number of bookings following each message delivery within 3 hours
The number of bookings made within X = 3 hours following each message delivery
Time frame: 3 hours
Number of bookings following each message delivery within 12 hours
The number of bookings made within X = 12 hours following each message delivery
Time frame: 12 hours
Plan to share: Yes — Proposals should be directed to kathysleung@connect.hku.hk; to gain access, data requestors will need to sign a data access agreement
Supporting information: Study protocol
Time frame: Beginning 9 months and ending 36 months following article publication
Access criteria: Researchers who provide a methodologically sound proposal for meta-analysis. Proposals should be directed to Kathyleung@connect.hku.hk; to gain access, data requestors will need to sign a data access agreement.
No publications or documents are linked to this record.
This study is completed, as verified in Aug 2022. You cannot join it, but the record below documents what was studied.
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