severe allergic reaction/anaphylaxis; hallucinations; accidentally given a 3 ml dose of the Moderna Covid-19 vaccine instead of 0.5 ml; nightly terrors; fear of dying; intermittent delusions that children were taken away; intermittent delusions that the vaccine was inside her and crawling through her skin; This case was received via an unknown source (no reference has been entered for a health authority or license partner) on 17-Mar-2021 and was forwarded to Moderna on 17-Mar-2021.    This spontaneous case was reported by a pharmacist and describes the occurrence of HALLUCINATION (hallucinations) and ANAPHYLACTIC REACTION (severe allergic reaction/anaphylaxis) in a 30-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 031A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included No adverse event (Medical history was not provided).    On 17-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 3 milliliter. In March 2021, the patient experienced SLEEP TERROR (nightly terrors), FEAR OF DEATH (fear of dying), DELUSION (intermittent delusions that children were taken away) and FORMICATION (intermittent delusions that the vaccine was inside her and crawling through her skin). On 17-Mar-2021, the patient experienced ANAPHYLACTIC REACTION (severe allergic reaction/anaphylaxis) (seriousness criterion hospitalization) and ACCIDENTAL OVERDOSE (accidentally given a 3 ml dose of the Moderna Covid-19 vaccine instead of 0.5 ml). On 24-Mar-2021, the patient experienced HALLUCINATION (hallucinations) (seriousness criterion medically significant). The patient was hospitalized from 17-Mar-2021 to 18-Mar-2021 due to ANAPHYLACTIC REACTION. In March 2021, ANAPHYLACTIC REACTION (severe allergic reaction/anaphylaxis) had resolved. On 17-Mar-2021, ACCIDENTAL OVERDOSE (accidentally given a 3 ml dose of the Moderna Covid-19 vaccine instead of 0.5 ml) had resolved. At the time of the report, HALLUCINATION (hallucinations), SLEEP TERROR (nightly terrors), FEAR OF DEATH (fear of dying), DELUSION (intermittent delusions that children were taken away) and FORMICATION (intermittent delusions that the vaccine was inside her and crawling through her skin) outcome was unknown.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   The patient did not have any psychological history; this was the first time she experienced hallucinations.  Treatment for the severe allergic reaction/anaphylaxis included intravenous steroids and hydrocortisone.  Treatment for hallucinations included droperidol and lorazepam.  Based on the current available information and temporal association between the use of the product and the start date of the event (anaphylactic reaction), a causal relationship cannot be excluded. Very limited information regarding the events (Hallucination, anaphylactic reaction, sleep terror, fear of death, delusion, and formication) has been provided at this time. This report refers to a case of (accidental overdose) for mRNA-1273, lot # 031A21A. Further information has been requested.   Most recent FOLLOW-UP information incorporated above includes: On 24-Mar-2021: Significant Follow up appended; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the event (anaphylactic reaction), a causal relationship cannot be excluded. Very limited information regarding the events (Hallucination, anaphylactic reaction, sleep terror, fear of death, delusion, and formication) has been provided at this time. This report refers to a case of (accidental overdose) for mRNA-1273, lot # 031A21A. Further information has been requested.