No adverse event; Received 0.25ml of Bivalent booster instead of 0.5 ml; This spontaneous case was reported by a nurse and describes the occurrence of ACCIDENTAL UNDERDOSE (Received 0.25ml of Bivalent booster instead of 0.5 ml) and NO ADVERSE EVENT (No adverse event) in a 41-year-old female patient who received mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (batch no. 057F22A) for COVID-19 vaccination.     Patient's allergies were denied by the reporter. The patient never diagnosed with/tested positive for COVID-19.  Concomitant products included INFLUENZA VACCINE INACT SPLIT 4V (FLUARIX QUADRIVALENT) for an unknown indication.    On 07-Oct-2022 at 5:00 PM, the patient received fourth dose of mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (unknown route) .25 milliliter. On 07-Oct-2022 at 5:00 PM, the patient experienced ACCIDENTAL UNDERDOSE (Received 0.25ml of Bivalent booster instead of 0.5 ml). On an unknown date, the patient experienced NO ADVERSE EVENT (No adverse event). At the time of the report, ACCIDENTAL UNDERDOSE (Received 0.25ml of Bivalent booster instead of 0.5 ml) and NO ADVERSE EVENT (No adverse event) outcome was unknown.        For mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (Unknown), the reporter considered NO ADVERSE EVENT (No adverse event) to be not related. No further causality assessment was provided for ACCIDENTAL UNDERDOSE (Received 0.25ml of Bivalent booster instead of 0.5 ml).    Concomitant medications details were not reported by the reporter.  On 25-Feb-2021, the patient received 1st dose of Moderna COVID-19 Vaccine 0.5 ml in left deltoid from lot/batch number 023M20A, on 25-Mar-2021, the patient received 2nd dose of Moderna COVID-19 Vaccine 0.5 ml in left deltoid from lot/batch number 016B21A and on 17-Nov-2021, the patient received 3rd dose of Moderna COVID-19 Vaccine 0.25 ml in left deltoid from lot/batch number 30145BA.  Upon follow up it was reported that the no adverse event reported by the patient.  Treatment details were not reported by the reporter.   This case was linked to US-MODERNATX, INC.-MOD-2022-665399, US-MODERNATX, INC.-MOD-2022-665435, US-MODERNATX, INC.-MOD-2022-665436, US-MODERNATX, INC.-MOD-2022-665437, US-MODERNATX, INC.-MOD-2022-665466, US-MODERNATX, INC.-MOD-2022-665472, US-MODERNATX, INC.-MOD-2022-665480, US-MODERNATX, INC.-MOD-2022-665491, US-MODERNATX, INC.-MOD-2022-665494, US-MODERNATX, INC.-MOD-2022-665504, US-MODERNATX, INC.-MOD-2022-665519, US-MODERNATX, INC.-MOD-2022-665541, US-MODERNATX, INC.-MOD-2022-665611, US-MODERNATX, INC.-MOD-2022-665613, US-MODERNATX, INC.-MOD-2022-665659, US-MODERNATX, INC.-MOD-2022-665669, US-MODERNATX, INC.-MOD-2022-665686, US-MODERNATX, INC.-MOD-2022-665696, US-MODERNATX, INC.-MOD-2022-665704, US-MODERNATX, INC.-MOD-2022-665705 (E2B Linked Report).   Most recent FOLLOW-UP information incorporated above includes: On 15-Dec-2022: Follow up received. Updated report type from invalid to spontaneous, added patient details, suspect details, updated event onset date and narrative.; Sender's Comments:  US-MODERNATX, INC.-MOD-2022-665399: US-MODERNATX, INC.-MOD-2022-665435: US-MODERNATX, INC.-MOD-2022-665436: US-MODERNATX, INC.-MOD-2022-665437: US-MODERNATX, INC.-MOD-2022-665466: US-MODERNATX, INC.-MOD-2022-665472: US-MODERNATX, INC.-MOD-2022-665480: US-MODERNATX, INC.-MOD-2022-665491: US-MODERNATX, INC.-MOD-2022-665494: US-MODERNATX, INC.-MOD-2022-665504: US-MODERNATX, INC.-MOD-2022-665519: US-MODERNATX, INC.-MOD-2022-665541: US-MODERNATX, INC.-MOD-2022-665611: US-MODERNATX, INC.-MOD-2022-665613: US-MODERNATX, INC.-MOD-2022-665659: US-MODERNATX, INC.-MOD-2022-665669: US-MODERNATX, INC.-MOD-2022-665686: US-MODERNATX, INC.-MOD-2022-665696: US-MODERNATX, INC.-MOD-2022-665704: US-MODERNATX, INC.-MOD-2022-665705: