The Virginia Department of Health has stopped administering the Johnson & Johnson COVID-19 vaccine while the federal government investigates “an extremely rare possible side effect” in people who have received the vaccine.

Those with upcoming appointments for the vaccine will be contacted to reschedule their appointments, said a press release.

“This pause is reassuring in that it demonstrates that the systems that are in place to monitor vaccine safety are working,” said the release.

While the investigation is underway, the rollout of the Pfizer and Moderna vaccines will continue, said the release.