Shortness of breath; loose bowels, cannot eat fiber; Bled a bit; Spasm in Neck; Temperature of 100.3; Chills very severe; Headache; Severe joint pain for her rotator cuffs and neck, tendons in arm, ribs, and all bones; Injection really hurt; Nausea; Knocked out from going up stairs and getting up chair now; Pain in tendons in her arm/ sore arm; Pain in ribs; Pain in all her bones; Rapid heartbeat/Palpitation Continues; This spontaneous case was reported by a consumer and describes the occurrence of LOSS OF CONSCIOUSNESS (Knocked out from going up stairs and getting up chair now) in a 77-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 021B21A and 036A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Arthritis (Patient had arthritis attack prior to vaccination.).   On 06-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 02-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 03-Apr-2021, the patient experienced LOSS OF CONSCIOUSNESS (Knocked out from going up stairs and getting up chair now) (seriousness criterion medically significant), TENDON PAIN (Pain in tendons in her arm/ sore arm), MUSCULOSKELETAL CHEST PAIN (Pain in ribs), BONE PAIN (Pain in all her bones), PALPITATIONS (Rapid heartbeat/Palpitation Continues), VACCINATION SITE HAEMORRHAGE (Bled a bit), PYREXIA (Temperature of 100.3), CHILLS (Chills very severe), HEADACHE (Headache), ARTHRALGIA (Severe joint pain for her rotator cuffs and neck, tendons in arm, ribs, and all bones) and VACCINATION SITE PAIN (Injection really hurt). 03-Apr-2021, the patient experienced MUSCLE SPASMS (Spasm in Neck) and NAUSEA (Nausea). On an unknown date, the patient experienced DYSPNOEA (Shortness of breath). an unknown date, the patient experienced DIARRHOEA (loose bowels, cannot eat fiber). The patient was treated with PARACETAMOL (TYLENOL) ongoing since an unknown date for Fever and Headache, at an unspecified dose and frequency and FEXOFENADINE HYDROCHLORIDE (ALLEGRA) ongoing since an unknown date for Allergic reaction, at an unspecified dose and frequency. On 05-Apr-2021, CHILLS (Chills very severe) had resolved. On 25-Apr-2021, TENDON PAIN (Pain in tendons in her arm/ sore arm), MUSCLE SPASMS (Spasm in Neck), PYREXIA (Temperature of 100.3) and NAUSEA (Nausea) had resolved. At the time of the report, LOSS OF CONSCIOUSNESS (Knocked out from going up stairs and getting up chair now), MUSCULOSKELETAL CHEST PAIN (Pain in ribs), BONE PAIN (Pain in all her bones), DYSPNOEA (Shortness of breath), VACCINATION SITE HAEMORRHAGE (Bled a bit), HEADACHE (Headache), ARTHRALGIA (Severe joint pain for her rotator cuffs and neck, tendons in arm, ribs, and all bones) and VACCINATION SITE PAIN (Injection really hurt) outcome was unknown and PALPITATIONS (Rapid heartbeat/Palpitation Continues) and DIARRHOEA (loose bowels, cannot eat fiber) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 03-Apr-2021, Body temperature: 100.3 (High) Temperature 100.3 Degree. On 01-Jun-2021, Cardiac monitoring: inconculsive (Inconclusive) Patient Wears a heart monitor.. On 16-Jun-2021, Antibody test: negative (Negative) Patient was reported to have no antibodies at all.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Patient's Date of Birth was reported to be 1944.  Chills were reported to be very severe and she could not get warm even with a heater on.  Patient was reported to have had a cardiogram done after consultation with physician.  No concomitant medications were reported.  Patient also reported that she could not eat fiber.  Patient still has heart palpitation and wears Heart monitor. The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was not applicable.  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 17-Jun-2021: Follow up was received on 17-JUN-2021. Lab data- antibody test was added. Additional event- diarrhea was added.. Event- Loss of consciousness was updated. Case was upgraded to serious- medically significant. Outcome of events- arthralgia, palpitations were updated. On 21-Jun-2021: Secondary reporter information was added. Added medical history Arthritis.Lab data-Cardiac monitoring was added. Added newevents spasm in neck and Nausea. Added stop date for sore arm/pain in tendon in her arm  event.; 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.