The National Health Service in the U.K. has issued a warning to people with a history of severe allergic responses after two health care workers experienced “anaphylactoid reactions” to the Pfizer COVID-19 vaccine. Yahoo News Medical Contributor Dr. Uché Blackstock explains what this means for the vaccine rollout in the U.S. — and why it’s not time to start panicking. Follow us on: Facebook: https://www.facebook.com/yahoonews Instagram: https://www.instagram.com/yahoonews/ Twitter: https://twitter.com/yahoonews TikTok: https://www.tiktok.com/@yahoonews Website: https://news.yahoo.com/ #COVIDVaccine #PfizerVaccine