I read something this morning that said recovering from the virus would give better protection to re-infection than the vaccine.
The study I read about watched something like 6500 people with only 44 catching it again. I think it said they were medical staff, so likely to become re-infected if it was possible.
*EDIT* It was on the DM but is a PHE study.
Data from Public Health England (PHE) comes from more than 20,000 healthcare workers at more than 100 sites across Britain to see how likely reinfection was.
www.dailymail.co.uk