Pfizer, Moderna Vaccines Less Effective Against Delta In Elderly And Protection Wanes Rapidly Four Months After Second Covid Shot, Study Finds

 Pfizer and Moderna’s Covid-19 vaccines are much less effective at preventing infection of senior citizens with the delta coronavirus variant and protection fades rapidly four months after the final jab, new research published in JAMA Network Open has found, as experts race to understand how effective the shots are against the fast-spreading, potentially vaccine-resistant omicron variant.