Governments have been very bullish when it comes to scientific matters. Most of the politicians don't have any technical knowledge, and even fewer are humble enough to accept their lack of knowledge and learn. I won't be surprised to hear that the government is demanding such aggressive deadlines to appeal to the common people.
Vaccines are used healthy people or people who haven;t been already affected by the disease. There is no point in giving a vaccine once someone's affected by the virus.