Third virus vaccine reaches major hurdle: final US testing

FILE - This July 18, 2020, file photo, shows the AstraZeneca offices in Cambridge, England. AstraZeneca announced Monday, Aug. 31, its vaccine candidate has entered the final testing stage in the U.S. The company said the study will involve up to 30,000 adults from various racial, ethnic and geographic groups.




"To have just one vaccine enter the final stage of trials eight months after discovering a virus would be a remarkable achievement; to have three at that point with more on the way is extraordinary," Health and Human Services Secretary Alex Azar said in a statement.

NIH Director Francis Collins tweeted that his agency "is supporting several vaccine trials since more than one may be needed. We have all hands on deck."


Meanwhile, a U.S. advisory panel was expected to release a draft plan Tuesday for how to ration the first doses of vaccine. The National Academies of Science, Engineering and Medicine will solicit public comments on its plan through Friday.

There's a good reason so many COVID-19 vaccines are in development.

"The first vaccines that come out are probably not going to be the best vaccines," Dr. Nicole Lurie, who helped lead pandemic planning under the Obama administration, said at a University of Minnesota vaccine symposium.




For now, here's a scorecard of vaccines that already have begun or are getting close to final-stage tests:



Neither uses the actual coronavirus. Instead, they're made with the genetic code for the aptly named "spike" protein that coats the surface of the coronavirus. Inject the vaccine containing that code, called mRNA, and the body's cells will make some harmless spike protein — just enough for the immune system to respond, priming it to react if it later encounters the real virus.

These mRNA vaccines are easier and faster to make than traditional vaccines, but it's a new and unproven technology.


Britain's Oxford University and AstraZeneca are making what scientists call a "viral vector" vaccine but a good analogy is the Trojan horse. The shots are made with a harmless virus — a cold virus that normally infects chimpanzees — that carries the spike protein's genetic material into the body. Once again, the body produces some spike protein and primes the immune system, but it, too, is a fairly new technology.

Two possible competitors are made with different human cold viruses.




Making vaccines by growing a disease-causing virus and then killing it is a tried-and-true approach — it's the way Jonas Salk's famed polio shots were made. China has three so-called "inactivated" vaccine candidates against COVID-19 made this way.




Novavax makes "protein subunit" vaccines, growing harmless copies of the coronavirus spike protein in the laboratory and packaging them into virus-sized nanoparticles.

There are protein-based vaccines against other diseases, so it's not as novel a technology as some of its competitors. But it only recently finished its first-step study; the U.S. government's Operation Warp Speed aims for advanced testing later in the fall.


AP journalist Danica Kirka in London contributed to this report.

