five allergic reactions that happened after people were administered Pfizer and BioNTech SE's coronavirus vaccine, the US Centers for Disease Control and Prevention has made recommendations on how people with histories of allergies should proceed.The US CDC on Saturday said it was monitoring reports of allergic reactions to the coronavirus vaccination.People who had a severe reaction to a vaccine against the novel coronavirus shouldn't get the second shot, the agency said, defining severe as needing the medication epinephrine or treatment in a hospital, reports news agency Reuters.The CDC also said that individuals who have had a severe allergic reaction to any ingredient in a Covid-19 vaccine should avoid the vaccine formulation containing.