Post-Marketing Safety Study in Japan of Shock and Anaphylaxis After Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA-1273 COVID-19 Vaccine in Persons in at High Risk of Severe COVID-19

Inclusion Criteria: * Participants registered to receive the mRNA-1273 vaccine in the Pep Up vaccination history Database * Participants who have a history of vaccination with the mRNA-1273 vaccine in the Pep-Up vaccination history Database and the observation start date is at least 6 months prior to vaccination with the mRNA-1273 vaccine and have underlying diseases. Data period for confirmation of presence/absence of underlying disease is May 2021 to November 2021. Exclusion Criteria: * Underlying diseases that were determined undetectable by the pre-screening of JMDC * Participants who did not consent to the questionnaire.