Arms felt very heavy; inflammatory process in my muscles; CPK Elevated; Bilateral leg paresis; Bilateral arm paresis; couldn't do normal activities; trouble walking; Couldn't lift herself up off bed/profound weakness; Low grade fever around 100.2 degree fahrenheit; Pain at injection site; Chills; Completely fatigued; Weird shakiness; This spontaneous case was reported by a health care professional (subsequently medically confirmed) and describes the occurrence of PARAPARESIS (Bilateral leg paresis), PARAPARESIS (Bilateral arm paresis), LIMB DISCOMFORT (Arms felt very heavy), ASTHENIA (Couldn't lift herself up off bed/profound weakness) and GAIT DISTURBANCE (trouble walking) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 013L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.  Concurrent medical conditions included Drug allergy. Concomitant products included MULTIVITAMIN ACTIVE WOMAN for Vitamin supplementation.    On 13-Jan-2021 at 12:30 PM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 13-Jan-2021, the patient experienced TREMOR (Weird shakiness) and FATIGUE (Completely fatigued). On 13-Jan-2021 at 5:30 PM, the patient experienced VACCINATION SITE PAIN (Pain at injection site) and CHILLS (Chills). On 13-Jan-2021 at 6:30 PM, the patient experienced PYREXIA (Low grade fever around 100.2 degree fahrenheit). On 13-Jan-2021 at 10:00 PM, the patient experienced ASTHENIA (Couldn't lift herself up off bed/profound weakness). On 18-Jan-2021, the patient experienced GAIT DISTURBANCE (trouble walking). On 23-Jan-2021, the patient experienced LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (couldn't do normal activities). On 23-Jan-2021 at 7:30 PM, the patient experienced PARAPARESIS (Bilateral arm paresis). On 23-Jan-2021 at 10:30 PM, the patient experienced PARAPARESIS (Bilateral leg paresis). On an unknown date, the patient experienced LIMB DISCOMFORT (Arms felt very heavy), MYOSITIS (inflammatory process in my muscles) and BLOOD CREATINE PHOSPHOKINASE INCREASED (CPK Elevated). On 15-Jan-2021, VACCINATION SITE PAIN (Pain at injection site), CHILLS (Chills) and PYREXIA (Low grade fever around 100.2 degree fahrenheit) had resolved. At the time of the report, PARAPARESIS (Bilateral leg paresis) and PARAPARESIS (Bilateral arm paresis) had not resolved and LIMB DISCOMFORT (Arms felt very heavy), ASTHENIA (Couldn't lift herself up off bed/profound weakness), GAIT DISTURBANCE (trouble walking), LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (couldn't do normal activities), MYOSITIS (inflammatory process in my muscles), BLOOD CREATINE PHOSPHOKINASE INCREASED (CPK Elevated), TREMOR (Weird shakiness) and FATIGUE (Completely fatigued) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 13-Jan-2021, Body temperature: 100.4 (Inconclusive) increased - 100.4 degree Fahrenheit. On an unknown date, Blood creatine phosphokinase: (High) CPK Elevated. On an unknown date, Body temperature: 100.1 increased - temperature was around 100.1 F.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered PARAPARESIS (Bilateral leg paresis), PARAPARESIS (Bilateral arm paresis), LIMB DISCOMFORT (Arms felt very heavy), ASTHENIA (Couldn't lift herself up off bed/profound weakness), GAIT DISTURBANCE (trouble walking), LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (couldn't do normal activities), MYOSITIS (inflammatory process in my muscles), BLOOD CREATINE PHOSPHOKINASE INCREASED (CPK Elevated), TREMOR (Weird shakiness), VACCINATION SITE PAIN (Pain at injection site), CHILLS (Chills), PYREXIA (Low grade fever around 100.2 degree fahrenheit) and FATIGUE (Completely fatigued) to be possibly related.    Lab Data Includes blood tests which came back negative, except for the CPK which was increased. The patient's neurologist said this could be a sign of an inflammatory process in her muscles, but could not explain why it happened, other than to say she thought I had a reaction to the Moderna COVID-19 vaccine. The HCP told her to informed if patient got worse and did not recommend the 2nd shot.  Patient says she's not back to normal. She has not been able to do the same amount of exercise and activity as before she had the Moderna vaccine. She continues to have off and on fatigue and weakness, mostly in her legs, which is affecting her quality of life. Treatment information was not provided.  Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.   Most recent FOLLOW-UP information incorporated above includes: On 19-May-2021: Updated Facility Information, Vaccination time, Patient demographic details, Lab data, Concomitant Medications and an Event is added; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.