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Report #2884360

Received Feb 5, 2026

A note on interpretation. VAERS reports are unverified and may be incomplete or coincidental. A report does not establish that a vaccine caused an event, and counts should not be used to calculate incidence or infer causation. Full disclaimer

Overview

Sex
Unknown
Age
Age unknown
State
CT
Recovered
Unknown
Vaccinated
Jan 27, 2026
Onset
—
Days to onset
—
Hospital days
—

Vaccines (1)

TypeNameManufacturerDoseLotRoute / Site
YFYELLOW FEVER (YF-VAX)SANOFI PASTEUR1—OT

Symptoms (2)

No adverse eventProduct preparation issue

Symptom narrative

administration of an incorrectly diluted dose of YF-VAX, with no reported adverse event; Initial information received on 03-Feb-2026 regarding an unsolicited valid non-serious case received from a pharmacist. This case involves an unknown age and unknown gender patient to whom administration of an incorrectly diluted dose of YELLOW FEVER VACCINE [YF-VAX], with no reported adverse. The patient's past medical history, medical treatment(s), vaccination(s) and family history were not provided. On 27-Jan-2026, the patient received Dose 1 of suspect YELLOW FEVER VACCINE Solution for injection, strength standard (dose, expiry date, batch number unknown) via intramuscular route in unknown administration site for immunization which was incorrectly diluted with no reported adverse event (product preparation error) (same day latency). Information on batch number and expiry date corresponding to the one at time of event occurrence was requested. It was reported "The diluent used was sterile water.List of concomitant vaccines: No other vaccine, treatment-None" Action taken- not applicable. This suspected adverse reaction report is submitted and classified as a medication error solely and exclusively to ensure the marketing authorization holder's compliance with the requirements set out in the Directive 2001/83/EC and Module VI of the Good Pharmacovigilance Practices. The classification as a medical error is in no way intended, nor should it be interpreted or construed as an allegation or claim made by the marketing authorization holder that any third party has contributed to or is to be held liable for the occurrence of this medication error.