The COVID-19 vaccine works by teaching your body to fight the virus, and protects you from getting sick. Receiving a vaccination helps your body to make more antibodies which can help your body to fight off sickness. You will need 2 doses of the vaccine in your arm, at least 21 days apart. To ensure you have the best protection, make sure you get both doses. The vaccine cannot give you COVID-19.
With COVID delta variant, it looks very much like 2 doses of the vaccine will not completely eliminate risk of infection – some people are still getting infected, having high viral loads and transmitting to others – but they are not getting severe illness or dying. So it still gives excellent protection again bad outcomes from infection. This is different to herd immunity.