May 11th 2021, white blood cells were even lower,2.7.; even lower white blood count, 2500; even lower white blood count, 2700; On March 16th had blood drawn in normal time and white bloods cells were low at 3.0 which is considered low.; low white blood count, 3000; This spontaneous case was reported by a consumer and describes the occurrence of WHITE BLOOD CELL COUNT DECREASED (On March 16th had blood drawn in normal time and white bloods cells were low at 3.0 which is considered low.), WHITE BLOOD CELL COUNT DECREASED (May 11th 2021, white blood cells were even lower,2.7.), WHITE BLOOD CELL COUNT DECREASED (low white blood count, 3000), WHITE BLOOD CELL COUNT DECREASED (even lower white blood count, 2700) and WHITE BLOOD CELL COUNT DECREASED (even lower white blood count, 2500) in a 67-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 012M20A and 011L20A) for COVID-19 vaccination.     The patient's past medical history included Type 2 diabetes mellitus on 01-Jan-2000.   On 13-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 10-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 01-Mar-2021, the patient experienced WHITE BLOOD CELL COUNT DECREASED (low white blood count, 3000). On 16-Mar-2021, the patient experienced WHITE BLOOD CELL COUNT DECREASED (On March 16th had blood drawn in normal time and white bloods cells were low at 3.0 which is considered low.). On 01-May-2021, the patient experienced WHITE BLOOD CELL COUNT DECREASED (even lower white blood count, 2700). On 01-Jun-2021, the patient experienced WHITE BLOOD CELL COUNT DECREASED (even lower white blood count, 2500). On an unknown date, the patient experienced WHITE BLOOD CELL COUNT DECREASED (May 11th 2021, white blood cells were even lower,2.7.). At the time of the report, WHITE BLOOD CELL COUNT DECREASED (On March 16th had blood drawn in normal time and white bloods cells were low at 3.0 which is considered low.), WHITE BLOOD CELL COUNT DECREASED (May 11th 2021, white blood cells were even lower,2.7.), WHITE BLOOD CELL COUNT DECREASED (low white blood count, 3000), WHITE BLOOD CELL COUNT DECREASED (even lower white blood count, 2700) and WHITE BLOOD CELL COUNT DECREASED (even lower white blood count, 2500) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 10-Jul-2020, White blood cell count: normal (normal) Normal. On 01-Mar-2021, White blood cell count: 3000 (Low) 3000. On 16-Mar-2021, White blood cell count: 3.0 (Low) 3.0. On 01-May-2021, White blood cell count: 2700 (Low) 2700. On 11-May-2021, White blood cell count: 2.7 (Low) 2.7. On 01-Jun-2021, White blood cell count: 2500 (Low) 2500. In July 2021, White blood cell count: 3500 (Low) 3500.         No concomitant medications were reported.  Patient reported that he was having type 2 diabetes mellitus and was having his blood drew every six months historically. The patient never had an issue with his blood test until Mar-2021.  It was reported that they were trying something, go back in another week for another blood test and taking off some diabetic medication to see if this affected. Patient stated that he was thinking of other changes, but major change was the vaccine. During this period, he visited his primary care physician a few times and eventually saw a hematologist. In July-2021, the count was back up to 3500. The patient and hematologist were not sure the cause was drug related or the vaccine.Patient preferred not to provide names of medication until safety contacts him.  Treatment information was not provided.   Most recent FOLLOW-UP information incorporated above includes: On 01-Aug-2021: Vaccine dose 1 lot number was added. Patient demographic details were added. Historical condition details were updated. Events were added. Laboratory tests were added. On 01-Aug-2021: Non-Significant follow up appended doc attached.