An investigation is under way into the death of a Gloucester woman hours after she received the COVID-19 vaccine. According to the Virginian-Pilot the 58-year-old woman received the Pfizer vaccine at a Warsaw clinic last Saturday and was being observed for post-dose side effects when she started having trouble breathing.The woman later died at Riverside Tappahannock Hospital.Virginia Vaccine Coordinator Dr. Danny Avula says investigators are looking for possible patterns and a causation versus just a correlation based on time.