is nowhere near enough to stop the spread of the delta variant and now health officials are bracing for an even bigger spike in infections. tonight, there are new fears of another covid surge in southernt spreading. l.a. and san diego counties are reporting their highest number of cases since february. how worried are you about the threat of the delta variant at this point? i m terrified. reporter: nationally new covid cases have spiked almost 50% with increases in all 50 states and 90% of u.s. jurisdictions, quinten lucas is the mayor of kansas city, missouri. i think every mayor of a major city in america is wondering if it s a time to return to mandates. reporter: florida is the nation s worst hot spot, accounting for more than one in five of all new cases. that didn t matter at miami s rolling loud music festival where thousands of people crammed together in california protestors rallied against vaccine requirements at this
care of one patient that i have gotten to remove the ventilator from and they succeed and get to move out of our unit. reporter: the delta variant highly contagious, and researchers are racing to discover whether it s deadlier, too. florida once again topping 10,000 cases a day. and this weekend, new superspreader concerns as tens of thousands flock to miami for rolling loud music festival. and tonight new questions about vaccine booster shots. the new york times reporting senior health officials now believe a third shot may be necessary for immunocompromised or elderly people who took the pfizer or moderna vaccines. the concern is immunocompromised people are more likely to get breakthrough infections, hospitalizations and deaths. reporter: the cdc has said it s exploring multiple options but notes more evidence is needed. o say reporter: sonya bryson-kirksey known for singing the national anthem at tampa bay lightning games is considered high risk because of multiple sc