People who get a vaccine (shot) can use the V-safe After Vaccination Health Checker tool on their smartphones: https://vsafe.cdc.gov/. This smartphone tool will check in on them after they get their shots. Adverse event reporting (the reporting of harmful side effects) should be done through the Vaccine Adverse Event Reporting System (VAERS): https://vaers.hhs.gov/esub/index.jsp.  

Please call or visit your healthcare provider if you have concerns about your health. If your symptoms are life-threatening, go to the emergency room or call 9-1-1.

You can also report side effects to ModernaTX, Inc. at 1-866-MODERNA (1-866-663-3762) or to Pfizer at 1-866-8337.