According to Dr. Robby SIkka, a physician who worked with many NFL and NBA teams, professional sports leagues have the unique ability to track breakthrough Covid cases. They test thousands of athletes every day.CNBC's Sikka said that the highly transmissible Delta variant drives most of the Covid breakthrough cases."Delta drives this," stated Sikka, founder of Sports Medicine Analytics Research Team. This organization assists many professional sports leagues with injury data.We know that the Delta variant of HIV has a higher viral load. It's more contagious and infectious than the others, which is driving the number of cases in the community. The community has a very high viral burden.New research shows that Covid cases are on the rise nationwide and that fully vaccinated individuals can pass the virus to others as asymptomatic carriers. According to the Centers for Disease Control and Prevention, more than 5,900 Americans who were fully vaccinated died from or were hospitalized for Covid-related complications between July 19 and July 19. According to the website, 1,821 cases were either unrelated or asymptomatic of Covid-19.Sikka stated that vaccines can prevent severe illnesses such as Covid and the delta variant. She also said that athletes who have been vaccinated return to sports sooner than those who have not.Sikka stated that athletes who received Covid vaccines, despite not being vaccinated, have returned to perform well and were able to perform at a high standard.