76% think not enough is known about the long-term effects. 71% are worried about side effects. and 66% are worried about future fertility problems. to be clear, fertility concerns have been repeatedly debunked. and excessive number of employees at new york city's fire department are calling in sick. this comes after friday's deadline mandating that most city workers provide proof they received at least one dose of the covid-19 vaccine or be placed on unpaid leave. cnn's polo sandoval reports. >> reporter: new york city's fire department said it was prepared to overcome any potential staffing issues they may experience after that vaccine mandate took effect friday evening. and authorities saying they're now implementing some of the protocols to make sure that no calls go unanswered. on saturday, the head of the new york fire department actually released a statement reporting what was described as excessive sick leave being taken by multiple firefighters.