count of 4  instead of a 100 platelets; they have little time left; have bruises on their arm and legs; felt sick; This spontaneous case was reported by a consumer and describes the occurrence of THROMBOCYTOPENIA (count of 4  instead of a 100 platelets) in a 77-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 004f21a) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Chronic lymphocytic leukemia. Concomitant products included CETIRIZINE HYDROCHLORIDE (ZYRTEC [CETIRIZINE HYDROCHLORIDE]) for an unknown indication.    On 24-Aug-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 07-Sep-2021, the patient experienced ILLNESS (felt sick). On 16-Sep-2021, the patient experienced CONTUSION (have bruises on their arm and legs). On an unknown date, the patient experienced THROMBOCYTOPENIA (count of 4  instead of a 100 platelets) (seriousness criterion medically significant) and GENERAL PHYSICAL HEALTH DETERIORATION (they have little time left). At the time of the report, THROMBOCYTOPENIA (count of 4  instead of a 100 platelets), ILLNESS (felt sick), CONTUSION (have bruises on their arm and legs) and GENERAL PHYSICAL HEALTH DETERIORATION (they have little time left) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Platelet count: count 4 instead of 100 (abnormal) count 4 instead of 100.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       No treatment medication details was provided. Chronic Lymphocytic Leukemia patient call to report that their doctor told them that they have a count of 4 instead of a 100 platelets, and that their body is having a bad reaction to the vaccine and these is taking place a couple of days after getting their second dose  of  the Moderna covid19 vaccine. They stated that they got the first dose of the Moderna covid19 vaccine on the 24Aug2021 on their left non dominant arm, and the second dose on the 21 Sept2021 with lot number 046c21a. Patient stated that on the 7 sept 2021 they felt sick, and on there 16 Sept they have bruises on their arm and legs, and on the 21Sep2021 they didn't feel good at all that day. Patient also stated that on the 18 Oct2021 they have bleeding in her mouth. Company comment: This is a spontaneous case concerning a 77-year-old female patient with relevant medical history of Chronic Lymphocytic Leukemia, who experienced serious, unexpected event of thrombocytopenia. The event occurred unknown days after the first dose of mRNA-1273. Doctor said that patient had a count of 4 instead of a 100 platelets. On 16-Sep patient experienced bruises on their arm and legs, on 18-Oct-2021 patient experienced bleeding in her mouth. Rechallenge is not applicable. Medical history of Chronic Lymphocytic Leukemia remains a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event seriousness assessed as per Medical judgment.   This case was linked to MOD-2021-367224 (Patient Link).; Sender's Comments: This is a spontaneous case concerning a 77-year-old female patient with relevant medical history of Chronic Lymphocytic Leukemia, who experienced serious, unexpected event of thrombocytopenia. The event occurred unknown days after the first dose of mRNA-1273. Doctor said that patient had a count of 4 instead of a 100 platelets. On 16-Sep patient experienced bruises on their arm and legs, on 18-Oct-2021 patient experienced bleeding in her mouth. Rechallenge is not applicable. Medical history of Chronic Lymphocytic Leukemia remains a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event seriousness assessed as per Medical judgment.