The Food and Drug Administration yesterday revised its emergency use authorizations for all COVID-19 antigen tests to authorize serial testing and require updates to product labeling regarding serial testing. As recommended in August, the revised EUAs and labeling call for users with COVID-19 symptoms to repeat testing at least twice over three days and users without symptoms to repeat testing at least three times over five days, with at least 48 hours between tests.In other news, the FDA yesterday designated the recall of 60,500 filters used in breathing systems a Class I recall, meaning the devices may cause serious injury or death. Teleflex recalled the Iso-Gard S filters in August. On Monday, FDA also alerted health care providers to a shortage of tracheostomy tubes, used to help people breathe after a tracheotomy, including a tube made by ICU Medical for pediatric patients. The agency recommends providers and other caregivers consider using certain conservation strategies.