Trial results for PROmotion of COVID-19 BOOSTer VA(X)Ccination in the Emergency Department (PROBOOSTVAXED) were posted on ClinicalTrials.gov on 2025-09-12, indicating that an intervention combining messaging and a vaccine question was associated with 14 participants achieving 30-day booster vaccine uptake, compared to 10 in the control group.
Background
COVID-19 continues to be a public health concern, and booster vaccinations are crucial for maintaining immunity and reducing severe outcomes. Emergency departments (EDs) serve as critical access points for healthcare, often seeing individuals who may not regularly engage with primary care or other vaccination sites. Leveraging ED visits to promote and facilitate booster vaccination presents a significant opportunity to improve public health. This trial aimed to investigate the effectiveness of different messaging and questioning interventions within the ED setting to increase COVID-19 booster vaccine uptake.
Trial design
This completed cluster randomized clinical trial, designated as Phase NA, enrolled a total of 919 participants. The study focused on individuals with COVID-19, specifically addressing booster vaccination. The trial's main goals were to determine if an intervention of vaccine messaging or an intervention of asking about vaccine acceptance could increase booster vaccine uptake at 30 days post-ED visit. The study also planned to examine the effects of recent national changes to funding and vaccine availability. The trial included three arms: "PROBOOSTVAXED Intervention M (Messaging + Vaccine Question)", "Intervention Q (Vaccine Question, No Messaging)", and "Control (No Messaging, No Vaccine Question)".
Key results
The posted results detail several key measurements related to booster vaccine uptake:
- For the outcome "Number of Participants With 30-day Booster Vaccine Uptake":
- The "PROBOOSTVAXED Intervention M (Messaging + Vaccine Question)" group recorded 14 participants.
- The "Intervention Q (Vaccine Question, No Messaging)" group recorded 11 participants.
- The "Control (No Messaging, No Vaccine Question)" group recorded 10 participants.
- For the outcome "Number or Participants Receiving Booster Vaccination in the ED":
- The "PROBOOSTVAXED Intervention M (Messaging + Vaccine Question)" group recorded 8 participants.
- The "Intervention Q (Vaccine Question, No Messaging)" group recorded 7 participants.
- The "Control (No Messaging, No Vaccine Question)" group recorded 0 participants.
- For the outcome "Number of Participants Stating They Would Accept Vaccine in the ED":
- The "PROBOOSTVAXED Intervention M (Messaging + Vaccine Question)" group recorded 73 participants.
- The "Intervention Q (Vaccine Question, No Messaging)" group recorded 90 participants.
What this means
The results suggest that interventions within the emergency department setting can influence COVID-19 booster vaccine uptake. The "PROBOOSTVAXED Intervention M," which combined messaging with a vaccine question, showed a slightly higher number of participants achieving 30-day booster uptake (14) compared to the control group (10). This intervention also led to 8 participants receiving a booster vaccination directly in the ED, whereas the control group had 0. The "Intervention Q," which involved only a vaccine question, also demonstrated some impact, with 11 participants achieving 30-day uptake and 7 receiving vaccination in the ED. These findings indicate that even simple interventions like asking about vaccine acceptance or providing targeted messaging in an ED setting could contribute to increased vaccination rates. The higher numbers of participants stating they would accept a vaccine in the ED (73 and 90 for the intervention groups) suggest a potential for further improving actual uptake through more robust or accessible vaccination services within these settings.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT06156215, titled "PROmotion of COVID-19 BOOSTer VA(X)Ccination in the Emergency Department - PROBOOSTVAXED", were posted on 2025-09-12 on clinicaltrials.gov.