An Epidemiologist on What to Expect From a Covid-19 Vaccine
Pfizer says they have a 90% effective vaccine. What does that mean?
The holy grail of Covid-19 has been, for most of the year, a vaccine. We’ve all been using “when we’ve got a vaccine” as a synonym for “back to normal,” because the only return to normalcy that we can really envision is based on everyone being immunized against infection. In all the conversations about how the pandemic might end, the one thing that is always featured is a vaccine that prevents the disease in the people who get it.
Which is why the recent Pfizer news feels momentous. The preliminary results from one of the first Phase 3 trials for a vaccine against Covid-19 have been reported, with Pfizer and BioNTech announcing that their vaccine is 90% effective at preventing Covid-19 at 28 days after the vaccine was given. All of a sudden, the hazy dreams of tomorrow where we are all safe from Covid-19 have become much more realistic in the near future.
But before we declare the pandemic officially over, it’s worth noting that this is just one more step in the long haul. Yes, these results are promising — and, I…
