Pfizer and BioNTech applied for an Emergency Use Authorization for their Covid-19 vaccine. But their clinical trials still need to continue. | Tayfun Coskun/Anadolu Agency via Getty Images

What the latest Covid-19 vaccine announcements from AstraZeneca-Oxford, Pfizer-BioNTech, and Moderna can and can’t tell us.

The recent results of Covid-19 vaccine clinical trials from teams at the University of Oxford and AstraZeneca, Moderna, and Pfizer and BioNTech have been some of the most exciting and promising developments in the pandemic to date.

All three vaccine candidates appear to be highly effective against Covid-19, the research teams say. Pfizer and BioNTech say their vaccine had an efficacy of 95 percent against Covid-19, meaning 95 percent of people who received the vaccine were protected against the disease. Moderna reported that its product was 94.5 percent effective. Oxford and AstraZeneca reported that theirs was 62 percent