I would like to report a positive side effect after receiving 4 doses of the Moderna COVID-19 vaccine; This spontaneous case was reported by a patient and describes the occurrence of THERAPEUTIC RESPONSE UNEXPECTED (I would like to report a positive side effect after receiving 4 doses of the Moderna COVID-19 vaccine) in a 79-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 066K21A, 014F21A, 038A21A and 011M20A) for COVID-19 prophylaxis.     The patient's past medical history included Herpes simplex (Patient had  been plagued with the Herpes Simplex 2, also knows as cold sores or fever blisters). Concurrent medical conditions included Polymyalgia rheumatica and Myelodysplasia. Concomitant products included DOCOSANOL (ABREVA) for Cold sores, DOXAZOSIN, PRAVASTATIN, CLOPIDOGREL, METHOTREXATE, FOLIC ACID, COLECALCIFEROL (VITAMIN D3), ACETYLSALICYLIC ACID (ASPIRIN ACTAVIS), IRON, MAGNESIUM and VARICELLA ZOSTER VACCINE RGE (CHO) (SHINGRIX) for an unknown indication.   On 02-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .5 milliliter. On 30-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .5 milliliter. On 22-Oct-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .25 milliliter. On 30-Mar-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to .25 milliliter. On an unknown date, the patient experienced THERAPEUTIC RESPONSE UNEXPECTED (I would like to report a positive side effect after receiving 4 doses of the Moderna COVID-19 vaccine). At the time of the report, THERAPEUTIC RESPONSE UNEXPECTED (I would like to report a positive side effect after receiving 4 doses of the Moderna COVID-19 vaccine) outcome was unknown.     The patient reported height 5 foot 10.5 inches, Patient reported height  used to be 5 foot 11.5 inches but has lost about an inch due to old age over the last 10 years.  The patient had no known allergies. It was unknown whether the patient had been diagnosed with/ tested positive for COVID 19.  Other vaccines given within 1 month prior to Moderna COVID-19 vaccine was reported as unknown  The patient reported a positive vaccine side effect after receiving 4 doses of the Moderna COVID-19 vaccine.  The patient reported that patient had been plagued with the Herpes Simplex 2  also known as cold sores or fever blisters through out patient's life. However, after receiving the Moderna COVID-19 vaccine, patient had not had any episodes of that. Patient reported that it just dawned at the time of report in the morning that certain things that would trigger episodes of cold sores, like eating peanuts or salty snack. All these had not been triggering those episodes anymore. Patient was able to eat all these trigger foods without any episode of cold sores. The patient would have at least one episode every quarter, but in the last year patient had not had any episodes at all.  Treatment information was not reported.   Most recent FOLLOW-UP information incorporated above includes: On 29-Jun-2022: Upon live follow-up concomitant medication added.