It may well be that having already been infected doesn't prevent you passing on the virus, in exactly the same way. Whether your immune system knows how to fig

It may well be that having already been infected doesn't prevent you passing on the virus, in exactly the same way. Whether your immune system knows how to fight the virus from previous infection, or from a vaccine, it can take time for your immune system to kick in and fight of a new infection. During that time you might be infectious.