pfizer trial showed first dose by itself was extremely effective. check out the chart here: https://www.businessinsider.com/how-well-pfizer-shot-works-against-c

pfizer trial showed first dose by itself was extremely effective. check out the chart here: https://www.businessinsider.com/how-well-pfizer-shot-works-against-covid-19-2020-12 https://www.businessinsider.com/how-well-pfizer-shot-works-a... Much of the data comparing efficacy of 1 vs 2 doses doesn't wait until 10-days after the first dose, which defeats the point. That being said 2 doses is more effective, just not by as much as you'd might think. edit: replaced the above link because it was pay-walled