Over 100,000 music fans packed shoulder to shoulder at Lollapalooza as the four-day music festival kicked off in Chicago. Concertgoers must either show proof of vaccination or a negative COVID-19 test. Vaccines are also being offered on site. Experts are saying everyone in attendance should assume they’ve been exposed to the virus and get tested afterwards. The CDC now says new research shows the delta variant is way more dangerous than previously thought.