Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022; No adverse event; 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose; Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022; This spontaneous case was reported by a pharmacist and describes the occurrence of WRONG PRODUCT ADMINISTERED (11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose), UNDERDOSE (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022), INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022) and NO ADVERSE EVENT (No adverse event) in a 61-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. AR6965B, 05N322A and 059H21A) for COVID-19 prophylaxis.     No Medical History information was reported.   On 20-Dec-2021 at 10:21 AM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .25 milliliter. On 19-Jul-2022 at 9:43 AM, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .25 milliliter. On 20-Jan-2023 at 10:09 AM, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .5 milliliter. On 19-Jul-2022 at 9:43 AM,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022). On 20-Jan-2023 at 10:09 AM, the patient experienced WRONG PRODUCT ADMINISTERED (11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose). On an unknown date, the patient experienced UNDERDOSE (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022) and NO ADVERSE EVENT (No adverse event). At the time of the report, WRONG PRODUCT ADMINISTERED (11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose), UNDERDOSE (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022), INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022) and NO ADVERSE EVENT (No adverse event) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered WRONG PRODUCT ADMINISTERED (11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose) and NO ADVERSE EVENT (No adverse event) to be not related. No further causality assessments were provided for UNDERDOSE (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022) and INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received first dose 0.25 ml on 20-Dec-2021 and second dose 0.25 ml on 19-Jul-2022).    Concomitant medications were not reported.  The patient received all doses in left side of body.  It was reported that Moderna monovalent vaccine was administered to approximately 20 patients from 11-Jan-2023 to 21-Jan-2023, instead of the Moderna bivalent booster. HCP wanted to know if these patients can receive the Moderna bivalent booster shot after that incorrect dose, and how long should they wait to receive it. The patient did not experience similar event in the past. The event did not cause patient to seek medical care. No other potential causes for the event.  Upon follow up they stated that there were only 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose.  Treatment information was not provided.  This case pertains to 13th of the total 20 patients.   This case was linked to US-MODERNATX, INC.-MOD-2023-704234 (Linked Report).   Most recent FOLLOW-UP information incorporated above includes: On 24-Jan-2023: Follow up received wherein the patient demographics, product and narrative updated. On 25-Jan-2023: Live follow-up document received contains no new information. On 06-Feb-2023: Significant follow up received contains route of administration added, event verbatim and narrative updated. On 06-Feb-2023: Follow-up document received contain no new information. On 07-Feb-2023: Follow-up document received contain no new information. On 15-Feb-2023: Significant follow-up received contains reporter details added, patient details added, suspect details added, event details and causality updated, narrative updated.; Sender's Comments:  US-MODERNATX, INC.-MOD-2023-704234.