Maternal exposure during pregnancy; Congestion and tested positive 3 days after testing negative and improved symptoms; This spontaneous prospective pregnancy case was reported by a patient and describes the occurrence of COVID-19 (Congestion and tested positive 3 days after testing negative and improved symptoms) and MATERNAL EXPOSURE DURING PREGNANCY (Maternal exposure during pregnancy) in a 33-year-old female patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis.    Co-suspect product included non-company product NIRMATRELVIR, RITONAVIR (PAXLOVID) for COVID-19 treatment.    Concurrent medical conditions included Drug allergy (Name of drug was not reported.). Concomitant products included BENZONATATE (TESSALON PERLE) from 12-Sep-2022 to 20-Sep-2022 for an unknown indication.   On 12-Sep-2022, the patient started NIRMATRELVIR, RITONAVIR (PAXLOVID) (unknown route) at an unspecified dose. On an unknown date, the patient received dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. The patient's last menstrual period was on an unknown date and the estimated date of delivery was 18-Jan-2023. On 20-Sep-2022,  after starting mRNA-1273 (Spikevax), the patient experienced COVID-19 (Congestion and tested positive 3 days after testing negative and improved symptoms). On an unknown date, the patient experienced MATERNAL EXPOSURE DURING PREGNANCY (Maternal exposure during pregnancy). At the time of the report, COVID-19 (Congestion and tested positive 3 days after testing negative and improved symptoms) had not resolved and MATERNAL EXPOSURE DURING PREGNANCY (Maternal exposure during pregnancy) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In September 2022, SARS-CoV-2 test: Negative. On 20-Sep-2022, SARS-CoV-2 test: Positive.     The action taken with mRNA-1273 (Spikevax) (Unknown) was unknown.       Relevant concomitant medications were not reported. The patient was taking other medications and products within 2 weeks of starting COVID-19 treatment.  Company comment- This spontaneous case concerns a 33-year-old pregnant patient with no relevant medical history, who experienced unexpected, non-serious AESI Covid-19 (with positive Sars-CoV test), which occurred at an unknown time with regards vaccination with mRNA-1273. Maternal exposure during pregnancy was reported as an additional event. The date of vaccination, last menstrual period and gestational age at the time of vaccination were unknown. The patient reported congestion and she tested positive 3 days after testing negative, with improved symptoms. The outcome of the event Covid-19 was reported as resolved. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Sender's Comments: This spontaneous case concerns a 33-year-old pregnant patient with no relevant medical history, who experienced unexpected, non-serious AESI Covid-19 (with positive Sars-CoV test), which occurred at an unknown time with regards vaccination with mRNA-1273. Maternal exposure during pregnancy was reported as an additional event. The date of vaccination, last menstrual period and gestational age at the time of vaccination were unknown. The patient reported congestion and she tested positive 3 days after testing negative, with improved symptoms. The outcome of the event Covid-19 was reported as resolved. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.