After Phase Three


Anchor lead: There are still many steps to getting a Covid-19 vaccine to market, Elizabeth Tracey reports

At least three vaccines against Sars-CoV2 are in later stage clinical trials domestically, with another just entering this phase. Andrew Pekosz, a vaccine expert at Johns Hopkins, says there’s no way to speed up the process.

Pekosz: These phase three trials just take time. Because you’re double-checking safety, you’re double-checking, in the case of a vaccine, what’s called immunogenicity, which is does the vaccine induce some sort of an immune response, and that immune response differs based upon the kind of vaccine you’re using, but the thing about phase three trials is it measures efficacy, so it actually goes out there and says, I’ve got a group here that’s been vaccinated, I’ve got a group here that’s been sham vaccinated, and we have less disease in our vaccinated group than in our sham group.  :30

Pekosz says exposure and potential infection with Sars-CoV2 is taking place naturally after a volunteer has been vaccinated, although in the UK there is consideration of exposing vaccinated volunteers to the virus to see if they are immune. At Johns Hopkins, I’m Elizabeth Tracey.