England's National Health Service has issued a warning about Pfizer's COVID-19 vaccine. Two health care workers who received the new vaccine on Tuesday - among the first in the entire world - suffered adverse reactions. UK regulators now advise people who suffer from "significant" allergic reactions to medicine or food should not take the new Pfizer coronavirus vaccine. Several drug makers, including Pfizer, are currently waiting for Emergency Use Authorization for the vaccine here in the U.S. from the FDA.