Several vaccinated people, including Olympic athletes, have tested positive for COVID-19 as the delta variant continues to spread. Should we be worried about these breakthroughs? UCSF Dr. Monica Ghandi discusses. Stay connected: Follow us on Twitter: http://www.twitter.com/nbcbayarea Like us on Facebook: http://www.facebook.com/nbcbayarea Follow us on Instagram: http://www.instagram.com/nbcbayarea Add us on Snapchat @NBCBayArea Catch up on all the day's news: http://www.nbcbayarea.com Download our app: On iOS: http://nbcbay.com/R1BhqYM On Android: http://nbcbay.com/rUcA97h