No adverse event; Patient was administered a lower than authorized dose of the Moderna COVID-19 bivalent vaccine; This spontaneous case was reported by a pharmacist and describes the occurrence of UNDERDOSE (Patient was administered a lower than authorized dose of the Moderna COVID-19 bivalent vaccine) and NO ADVERSE EVENT (No adverse event) in an elderly patient of an unknown gender who received mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (batch no. 061F22A) for COVID-19 prophylaxis.     No Medical History information was reported.    On 27-Oct-2022, the patient received dose of mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (unknown route) .25 milliliter. On 27-Oct-2022, the patient experienced UNDERDOSE (Patient was administered a lower than authorized dose of the Moderna COVID-19 bivalent vaccine). On an unknown date, the patient experienced NO ADVERSE EVENT (No adverse event). At the time of the report, UNDERDOSE (Patient was administered a lower than authorized dose of the Moderna COVID-19 bivalent vaccine) 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 UNDERDOSE (Patient was administered a lower than authorized dose of the Moderna COVID-19 bivalent vaccine).    No concomitant drug was reported. The patient received 0.25 mL dose instead of 0.5 mL dose (Lot: 061F22A, Expiration date: 16MAY2023) of  the Moderna COVID-19 bivalent vaccine The patient had not reported any adverse reactions at that time. No treatment drug was reported. This case contains information for the 16th of 18 elderly patients described by the reporter.   This case was linked to US-MODERNATX, INC.-MOD-2022-666063, US-MODERNATX, INC.-MOD-2022-666248, US-MODERNATX, INC.-MOD-2022-666249, US-MODERNATX, INC.-MOD-2022-666250, US-MODERNATX, INC.-MOD-2022-666251, US-MODERNATX, INC.-MOD-2022-666252, US-MODERNATX, INC.-MOD-2022-666255, US-MODERNATX, INC.-MOD-2022-666277, US-MODERNATX, INC.-MOD-2022-666278, US-MODERNATX, INC.-MOD-2022-666279, US-MODERNATX, INC.-MOD-2022-666281, US-MODERNATX, INC.-MOD-2022-666282, US-MODERNATX, INC.-MOD-2022-666283, US-MODERNATX, INC.-MOD-2022-666284, US-MODERNATX, INC.-MOD-2022-666286, US-MODERNATX, INC.-MOD-2022-666290, US-MODERNATX, INC.-MOD-2022-666295, US-MODERNATX, INC.-MOD-2022-666277 (E2B Linked Report).; Sender's Comments:  US-MODERNATX, INC.-MOD-2022-666063: US-MODERNATX, INC.-MOD-2022-666248: US-MODERNATX, INC.-MOD-2022-666249: US-MODERNATX, INC.-MOD-2022-666250: US-MODERNATX, INC.-MOD-2022-666251: US-MODERNATX, INC.-MOD-2022-666252: US-MODERNATX, INC.-MOD-2022-666255: US-MODERNATX, INC.-MOD-2022-666277: US-MODERNATX, INC.-MOD-2022-666278: US-MODERNATX, INC.-MOD-2022-666279: US-MODERNATX, INC.-MOD-2022-666281: US-MODERNATX, INC.-MOD-2022-666282: US-MODERNATX, INC.-MOD-2022-666283: US-MODERNATX, INC.-MOD-2022-666284: US-MODERNATX, INC.-MOD-2022-666286: US-MODERNATX, INC.-MOD-2022-666290: US-MODERNATX, INC.-MOD-2022-666295: US-MODERNATX, INC.-MOD-2022-666277:Patient 16