Israeli researchers report that an additional dose of Pfizer (NYSE:PFE) and BioNTech’s (NISDQ:BNTX) COVID-19 vaccine leads to notable improvements in immunity in people 60 and older. The protection against infection increased fourfold 10 days after administration of the third dose, according to scientists at the Gertner Institute (Ramat Gan, Israel) and KI Institute (Kfar Malal, Israel).…