No adverse event; There were only 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose/ Patient was to get Bivalent but received monovalent; 0.25 ml received for Dose 1 instead of 0.5 ml; This spontaneous case was reported by a pharmacist and describes the occurrence of WRONG PRODUCT ADMINISTERED (There were only 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose/ Patient was to get Bivalent but received monovalent), UNDERDOSE (0.25 ml received for Dose 1 instead of 0.5 ml) and NO ADVERSE EVENT (No adverse event) in a 69-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. AR6965B, 7H593 and 059H21A) for COVID-19 prophylaxis.     It was unknown if patient was ever been diagnosed with/ tested positive for COVID-19. Patient had no acute illnesses at the time of vaccination and up to one month before. Patient had no chronic or long-standing health conditions. Patient did not had any prescriptions, over-the-counter medications, dietary supplements, or herbal remedies taken at time of vaccination and/or at the time of the adverse event. Patient had no known drug allergies.    On 20-Dec-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .25 milliliter. On 19-Jan-2022, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .5 milliliter. On 20-Jan-2023, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .5 milliliter. On 20-Dec-2021 at 10:21 AM, the patient experienced UNDERDOSE (0.25 ml received for Dose 1 instead of 0.5 ml). On 20-Jan-2023 at 10:49 AM, the patient experienced WRONG PRODUCT ADMINISTERED (There were only 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose/ Patient was to get Bivalent but received monovalent). On an unknown date, the patient experienced NO ADVERSE EVENT (No adverse event). At the time of the report, WRONG PRODUCT ADMINISTERED (There were only 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose/ Patient was to get Bivalent but received monovalent), UNDERDOSE (0.25 ml received for Dose 1 instead of 0.5 ml) and NO ADVERSE EVENT (No adverse event) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered WRONG PRODUCT ADMINISTERED (There were only 11 patients instead of 20 patients who were inadvertently administered with the monovalent vaccine instead of the bivalent booster dose/ Patient was to get Bivalent but received monovalent) and NO ADVERSE EVENT (No adverse event) to be not related. No further causality assessment was provided for UNDERDOSE (0.25 ml received for Dose 1 instead of 0.5 ml).    Concomitant medication was not provided.  HCP stated that they had a situation at the pharmacy where Moderna monovalent vaccine was administered to approximately 20 patients from 11-Jan-2023 to 21-Jan-2023, instead of the Moderna bivalent booster.   Later upon follow up reporter called back on 06-Feb-2023 at 3:35pm and 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.  Patient administered the Dose 1 at 10:21 am on 20-Dec-2021, Dose 2 at 10:07 am on 19-Jan-2022 and Dose 3 at 10:49 am on 20-Jan-2023.  Treatment information was not reported.   This case was linked to US-MODERNATX, INC.-MOD-2023-704234 (E2B Linked Report).   Most recent FOLLOW-UP information incorporated above includes: On 24-Jan-2023: Follow-up received on 24-Jan-2023 with patient details and vaccination date added. On 25-Jan-2023: Follow-up document received on 25-Jan-2023 with no new information. On 06-Feb-2023: Follow-up document received on 06-Feb-2023 with no new information received. On 06-Feb-2023: Follow-up information received on 06-Feb-2023 includes vaccine route of administration, event verbatim and I-narrative supplement were updated. On 07-Feb-2023: Follow-up document received on 07-Feb-2023 contains no new information. On 15-Feb-2023: Upon receipt of the follow-up for the case MOD-2022-704882 on 15-Feb-2023, it was identified that the case MOD-2022-704882 was created with year 2022 however Initial IRD of the report was 23-Jan-2023. Hence, the case MOD-2022-704882 was nullified from the database and a newcase MOD-2023-710801 was created. Follow-up document received on 15-Feb-2023 for the case MOD-2022-704882 with Vaccination details and Event added.; Sender's Comments:  US-MODERNATX, INC.-MOD-2023-704234:Master