Share on Twitter His situation has raised suspicion that he could be among the people who continue to shed the virus well after the infectious period. That was the case for American tennis star Tennys Sandgren, who was allowed by health authorities to travel to Melbourne for the Australian Open, despite testing positive for COVID-19. His medical evaluations showed that although his body was still shedding the virus, he did not represent a risk of contagion. But Miller does not have the freedom or opportunity to undergo the same medical tests to show that he no longer represents a biosecurity risk, says Dr Sara Carrillo, an expert in public health policies at Monash University.