This spontaneous case was reported by a consumer and describes the occurrence of THROMBOSIS (was very worried about a blood clot) in a 69-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 060A22A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below. No Medical History information was reported. On 23-Jun-2022, the patient received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In June 2022, the patient experienced THROMBOSIS (was very worried about a blood clot) (seriousness criterion medically significant). On 23-Jun-2022, the patient experienced VACCINATION SITE PAIN (she reports when she got the injection, she was amazed at how much pain she was in, but it was just for 10 minutes). On 24-Jun-2022, the patient experienced GAIT INABILITY (could barely walk around, legs not 100 percent) and PAIN IN EXTREMITY (legs were killing her, sharp pain, almost like an electric zap, she was driving, she had to take her foot off the accelerator, because the pain was so intense). On an unknown date, the patient experienced EXPOSURTO SARS-COV-2 (was around people with COVID). On 23-Jun-2022, VACCINATION SITE PAIN (she reports when she got the injection, she was amazed at how much pain she was in, but it was just for 10 minutes) had resolved. At the time of the report, THROMBOSIS (was very worried about a blood clot), GAIT INABILITY (could barely walk around, legs not 100 percent) and EXPOSURE TO SARS-COV-2 (was around people with COVID) outcome was unknown and PAIN IN EXTREMITY (legs were killing her, sharp pain, almost like an electric zap, she was driving, she had to take her foot off the accelerator, because the pain was so intense) was resolving. Patient had received all the previous doses of the Moderna COVID-19 Vaccines and reported nothing big in terms of side effects just felt tired. Patient had received all the doses in her left arm, since patient was right handed. Patient reported that the next day of fourth dose, she could barely walk around. Patient felt that her legs are not 100 percent. Patient reports that she had not been sick with COVID, even though she was around people with COVID. No concomitant and treatment product was provided. Company comment: This spontaneous case concerns a 69-year-old, female patient with no medical history reported, who experienced the unexpected serious (medically significant) AESI event of thrombosis, which occurred unspecified days after fourth dose of mRNA-1273 vaccine. Additionally non serious events gait instability, pain in extremity is also reported. It is reported that after fourth dose of vaccination patient could barely walk, patient legs were killing her and had sharp pain almost like electric zap and patient take foot off the accelerator because pain was so intense, patient worried about blood clot, with previous Moderna COVID-19 vaccines, patient being tried with no other side effects, had pain at the injection site but it was just 10 minutes, patient was not sick with COVID but people around was with Covid. The benefit-risk relationship of mRNA-1273 is not affected by this report. This case was linked to MOD-2022-595683 (Patient Link). Sender's Comments: This spontaneous case concerns a 69-year-old, female patient with no medical history reported, who experienced the unexpected serious (medically significant) AESI event of thrombosis, which occurred unspecified days after fourth dose of mRNA-1273 vaccine. Additionally non serious events gait instability, pain in extremity is also reported. It is reported that after fourth dose of vaccination patient could barely walk, patient legs were killing her and had sharp pain almost like electric zap and patient take foot off the accelerator because pain was so intense, patient worried about blood clot, with previous Moderna COVID-19 vaccines, patient being tried with no other side effects, had pain at the injection site but it was just 10 minutes, patient was not sick with COVID but people around was with Covid. The benefit-risk relationship of mRNA-1273 is not affected by this report.