Djokovic had Covid in June (that's still accepted, right?). He is in the highest risk group for myocarditis from the vaccination. Omicron is dominant. Vaccine e

Djokovic had Covid in June (that's still accepted, right?). He is in the highest risk group for myocarditis from the vaccination. Omicron is dominant. Vaccine efficacy against Omicron is low. What is the scientific basis for mandating that he must be vaccinated in order to participate?