Pfizer studying third COVID-19 vaccine dose to fight new strains Fox NewsA third Pfizer dose? The Covid-19 vaccine maker is studying booster shots. NBC NewsVaccines, excellent real world data Dr. John CampbellPfizer COVID-19 vaccine 94% effective in real-world conditions: study Fox NewsCanada sees good news about COVID-19 inoculations as doses arrive more quickly Yahoo NewsView Full Coverage on Google News