Virginia is ceasing the use of all Johnson & Johnson vaccines while the federal government investigates rare reports of potentially dangerous blood clots among recipients of the vaccine. Virginia State Vaccination Coordinator Dr. Danny Avula said in a statement Tuesday morning that the state was halting use of the vaccine until the federal investigation is complete. Avula said the pause demonstrates that the systems in place to monitor safety are working. Federal officials said Tuesday they are investigating unusual clots in six women. More than 6.8 million doses of the J&J vaccine have been administered in the U.S., the vast majority with no or mild side effects.