What would you do?

Just received a letter saying that if I don't get my Flu Vacc by now, I will not be able to continue working from 12am on the 11th. They claim the knowledge of this was well communicated the past month, but there has been nothing about it at work and the first email from them mentioning it was 2 days ago...Its 4:23 pm now and I work nights... Bastards!... I was looking to get time off work soon anyway.