Testing timeline: What’s ahead for COVID-19 vaccines
Pfizer's surprising news that its COVID-19 vaccine might offer more protection than anticipated — an announcement right after a fraught U.S. presidential election campaign — is raising questions about exactly how the different shots will make it to market.
Pfizer Inc. and the maker of the other leading U.S. vaccine candidate, Moderna Inc., have been cautioning for weeks that the earliest they could seek regulatory approval for wider use of their shots would be late November. In Britain, AstraZeneca recently said it hoped to prove its own vaccine was effective by year’s end.
The hard truth: Science moves at its own pace. While COVID-19 vaccines are being developed at record speeds in hope of ending the pandemic, when they’re ready for prime time depends on a long list of research steps including how many study volunteers wind up getting the coronavirus — something scientists cannot control.
Here’s a look at the process:
HOW THE STUDIES WORK
Pfizer and its German partner BioNTech have enrolled nearly 44,000 people in final testing of their vaccine. Neither participants, their doctors nor Pfizer know who gets the real vaccine and who gets a dummy shot. They get a second dose about three weeks after the first.
And then another week after the second dose, key tracking begins: Counting anyone who experiences COVID-19 symptoms and tests positive for the virus as participants go about their daily routines, especially in hot spots.
Late-stage testing of other vaccine candidates is similar, varying slightly in the number of volunteers and timing.
HOW TO TELL SHOTS WORK
Every vaccine study is overseen by an independent “data and safety monitoring board,” or DSMB. These boards include scientists and statisticians who have no ties to the vaccine makers.
Before a...
