(Reuters) -Some employees at CVS Health Corp and Walgreens Boots Alliance's U.S. pharmacies launched a three-day walkout starting Monday to push the companies to improve working conditions and add more staff to their stores. The walkout, which has been dubbed "Pharmageddon" on social media platforms such as Meta's Facebook where it was largely planned, started on Monday and led to the closing of some stores in New York City, two organizers told Reuters. Shane Jerominski, a former Walgreens pharmacist and one of the organizers of the walkout, told Reuters that as many as 5,000 pharmacy workers would walk out across the three days, but said that the exact number of affected stores and participating staff was not clear due to the lack of a union.