An interventional study of Flu vaccination guide and Accident safety guide in Influenza, Human and Vaccine Hesitancy, sponsored by Calypta Systems, Inc.. Active, not recruiting at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Calypta Systems, Inc. · Not applicable, Interventional, and Prevention
Among 965 studies in Influenza, Human with a site in United States — 60 open to participants now, 84 under way, 7 of them phase 3. Influenza, Human · United States.
Among the 965 studies in Influenza, Human with a site in United States, this one is the 453rd largest by planned enrollment of the 842 interventional ones, is one of 26 that started in 2026, is one of 160 with no phase, reaches primary completion later than 16 of the 82 other live ones, and was the 964th registered.
2,356 studies on the registry are indexed under Influenza, Human; 184 are open to participants now.
This study's planned enrollment of 220 is close to the median of 227 across 1,957 interventional studies indexed under Influenza, Human.
Browse Influenza, Human studies →60 of the 965 studies in Influenza, Human with a site in United States are open now, in 12 countries. Each count lists the studies.
Of the 119 Influenza, Human studies recruiting now, 62 (52%) set no upper age limit and 47 (39%) stop at 75 or younger; 31 take children under 18; 65 take healthy volunteers.
This study: 18 Years and older · all sexes · healthy volunteers too.
The full table on the hub →965 studies; the count open now beside each. This study's row is marked.
First in 1997; this study’s year is marked. 26 started in 2026.
Median enrollment 273 across the 842 interventional studies, 261 across the 122 observational. Of the 841 that completed or were terminated, 433 (51%) have results posted.
434 of 965 have an industry lead sponsor. The 10 most frequent:
This is the only study on the registry with Calypta Systems, Inc. as lead sponsor.
Calypta Systems, Inc. has 1 study filed under Influenza, Human — fewer than ten, so there is no comparison to draw.
40 of the studies in Influenza, Human with a site in United States that are under way reach primary completion within a year, 5 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07496450Phase 3ModernaTX, Inc.A Study of mRNA-1018-H5 Pandemic Influenza Vaccine in Healthy Adults | 2027-01-28 |
| NCT06094010Phase 3Hoffmann-La RocheA Surveillance Study of Susceptibility to Baloxavir Marboxil in Pediatric Participants With Influenza and Transmission of Influenza to Household Contacts | 2027-05-11 |
| NCT07159763Phase 3Cidara Therapeutics Inc., a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)A Study to Evaluate the Safety and Efficacy of MK-1406/CD388 for Prevention of Influenza (MK-1406-005/CD388.SQ.3.06) | 2027-06-30 |
| NCT07851246Phase 3GlaxoSmithKlineA Study to Evaluate the Immune Response and Safety of a Vaccine Against Influenza in Adults 18-64 Years of Age | 2027-07-09 |
| NCT05624450Phase 3AstraZenecaEfficacy and Safety of Tozorakimab in Patients Hospitalised for Viral Lung Infection Requiring Supplemental Oxygen | 2027-11-04 |
Among the 965 studies in Influenza, Human with a site in United States, from their registry updates:
This randomized trial tests whether an online guide combining short evidence cards with an AI-guided conversation increases flu-vaccination intention among US adults who haven't decided whether to get a flu vaccine this season. Participants recruited through Prolific are randomly assigned to the flu guide or to a structure-matched guide about everyday accident safety. The primary outcome is self-rated likelihood of getting a flu vaccine this season (1-7), asked immediately after the session. Participants are asked at about 2 and 8 weeks whether they have been vaccinated. The study is powered for the intention outcome but not for vaccination. For vaccination, it estimates the effect, the base rate, and follow-up response, to size a later, larger trial.
In a prior randomized trial by the same investigator, a similar intervention (evidence cards followed by an AI-guided motivational-interviewing conversation) raised MMR vaccination intention among hesitant parents by about one point on a 1-7 scale relative to an active control (Forman 2025, PsyArXiv, doi:10.31234/osf.io/5kteh_v1). This study tests whether the effect transfers to a different decision and population: adult seasonal flu vaccination.
Design: two-arm, parallel, 1:1 randomized trial conducted entirely online. Participants are US adults on Prolific (approval rate ≥ 99%, at least 25 previous submissions), desktop or mobile. A five-item health-plans screener masks the eligibility question; eligible participants answer "Probably", "Unsure", or "Probably not" to getting a flu vaccine in the next few months. Participants then answer the baseline intention item; those answering 7 are screened out before randomization. Randomization is by minimization within screener stratum (probably / unsure / probably not), with random tie-breaking. Up to 220 are randomized; dropouts are not replaced.
Intervention: a study version of Calypta Health's public flu vaccination guide: an intro card and 12 evidence cards (including an interactive simulation), followed by a conversation with an AI model (a Claude model accessed through Amazon Bedrock; the model and its instructions are fixed for the study's duration). Control: a study-only guide on everyday accident avoidance (mostly driving, plus falls and smoke and carbon-monoxide alarms) with the same structure, card count, minimum reading time, and conversation rules. In both arms, per-card minimum times (10 seconds for the intro card, 20 seconds for each other card) and a minimum conversation length (at least 3 rounds and 100 engagement points) apply. After the post-session question, participants in either arm who answer 6 or 7 are offered the same optional flu-vaccination plan card (where and which day). Because the card is offered only after a 6 or 7, more flu-arm participants may see it, so the vaccination comparison includes any effect of the card.
Follow-up: check-ins at about 2 and 8 weeks, each a separate Prolific study open to everyone randomized, ask about flu vaccination since the session, intention, and (as a negative-control outcome) dental cleanings or checkups.
Analysis: the primary outcome is analyzed by ANCOVA adjusting for baseline intention and screener stratum, with HC3 standard errors, two-sided α = .05. The analysis set is randomized participants who completed the session and met the engagement rule; the primary population excludes sessions that an AI reviewer links as one person using two accounts, sensitivity analyses include everyone or remove sessions flagged as low quality, and a further analysis is limited to participants with a baseline intention of 5 or below. Analysis code for the primary outcome is written and frozen before arm labels are unblinded; check-in outcomes are analyzed as the preregistered plan specifies once each wave closes, with any deviation reported. A full analysis plan is preregistered on OSF and linked from this record.
A feasibility pilot (20 randomized, 2026-10-15), under the same IRB approval, preceded main enrollment to test study mechanics and a next-day follow-up; pilot data are not presented as results of this study or combined with main-study data, and pilot participants are excluded from the main study.
Conflict of interest: the investigator founded Calypta Systems, Inc. and is its CEO, sole director, and majority shareholder. Calypta makes the flu guide and funds the study. Results will be made public regardless of outcome.
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:
Calypta Health's flu vaccination guide: 12 evidence cards followed by an AI-guided conversation.
Behavioral: Flu vaccination guide
An attention-matched control: a structure-matched guide on everyday accident avoidance, 12 evidence cards followed by an AI-guided conversation, with no flu or vaccine content.
Behavioral: Accident safety guide
Online guide with 12 evidence cards on seasonal flu and flu vaccines (including an interactive simulation of flu risk), with per-card minimum reading times, followed by a text or voice conversation with an AI model instructed to use motivational-interviewing techniques and to draw on curated, cited sources. The session takes about 10 to 20 minutes.
Online guide with 12 evidence cards on everyday accident avoidance (driving, falls, and smoke and carbon-monoxide alarms; including an interactive seatbelt simulation), with matched minimum reading time, followed by an AI conversation under the same rules. The session takes about 10 to 20 minutes.
Flu vaccination intention
"How likely are you to get a flu vaccine this season?" 1 (Definitely not) to 7 (Definitely yes), asked identically at baseline and post-session. Analyzed as the post-session score adjusted for baseline and stratum.
Time frame: Immediately after the session (about 10 to 20 minutes after baseline)
Self-reported flu vaccination
Proportion of check-in B respondents who answered "Yes, I've gotten a flu vaccine" at either check-in (about 2 or about 8 weeks) to "Since you took part in our study on \[the participant's session date, e.g. October 15\], have you gotten a flu vaccine?"
Time frame: About 8 weeks after the session
Flu vaccination intention or vaccination at 2 weeks
The 1-7 intention item at the check-in, with participants vaccinated by that check-in coded 7, adjusted for baseline and stratum.
Time frame: About 2 weeks after the session
Flu vaccination intention or vaccination at 8 weeks
As above, at check-in B, where vaccinated means a yes at either check-in.
Time frame: About 8 weeks after the session
Self-reported dental cleaning or checkup (negative control)
Exploratory negative-control outcome: proportion of check-in B respondents who reported a dental cleaning or checkup since the session at either check-in.
Time frame: About 8 weeks after the session
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — De-identified structured variables only (screener answers, intention measures, arm, stratum, engagement counts, check-in answers, and the coarse demographic and device groups used in the analyses by group) under study codes. Not shared: Prolific IDs, conversation transcripts.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Analytic code
Time frame: Data will be shared when the results preprint is posted, expected in January 2027.
Access criteria: Open to anyone, with no request or data use agreement, from a public repository (OSF, or another repository that issues a DOI).
Ran from Oct 2026 to primary completion in Oct 2026, 0 months.
Of 166 interventional studies with no phase under Influenza, Human, half reached primary completion within 6 months of starting (the median), counting those still running; a quarter within 3 and three quarters within 16. This study's 0 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.