Pfizer’s vaccine “may be more than 90% effective.” (Mahase, BMJ 2020;371:m4347, November 9) Specific data are not given but it is easy enough to approximate the numbers involved, based on the 94 cases in a trial that has enrolled about 40,000 subjects: 8 cases in a vaccine group of 20,000 and 86 cases in a … Continue reading Covid-19 vaccine candidate is unimpressive: NNTV is around 256 – BMJ