Third vaccine against virus hits major hurdle: final testing in US


A handful of the dozens of experimental COVID-19 vaccines in human tests have hit the last and biggest hurdle: Seeking evidence needed that they work as a U.S. advisory group suggested a way to ration on Tuesday the first limited doses once a vaccine is approved.

AstraZeneca announced Monday that its vaccine candidate has entered the final stages of testing in the United States. The Cambridge, England-based company said the study would involve up to 30,000 adults from various racial, ethnic and geographic groups.


Two other candidate vaccines began final testing on tens of thousands of people in the United States this summer. One was created by the National Institutes of Health and manufactured by Moderna Inc., and the other developed by Pfizer Inc. and Germany BioNTech.

“Getting a single vaccine into the final phase of testing eight months after a virus is discovered would be a remarkable achievement; to have three at this time with others on the road is amazing, ”Health and Human Services Secretary Alex Azar said in a statement.

FILE – In this file photo from August 14, 2020, lab technicians work at biopharmaceutical company mAbxience on an experimental coronavirus vaccine developed by the University of Oxford and the AstraZeneca lab in Garin, Argentina. AstraZeneca announced Monday, August 31, that its vaccine candidate has entered the final stages of testing in the United States (AP)

NIH Director Francis Collins tweeted that his agency “supports multiple vaccine trials because more than one may be needed. We all have our hands on the bridge ”.

AstraZeneca said development of the vaccine, known as AZD1222, is advancing around the world with advanced stage trials in the UK, Brazil and South Africa. Further trials are planned in Japan and Russia. The potential vaccine was invented by the University of Oxford and an associated company, Vaccitech.

Meanwhile, a U.S. advisory group on Tuesday released a draft plan on how to ration the first doses of the vaccine. The national academies of science, engineering and medicine have offered to administer the first doses of the vaccine – initial supplies should be limited to 15 million people – to high-risk health workers and first responders.

Next, older residents of nursing homes and other overcrowded facilities and people of all ages with health conditions that put them at significant risk would be prioritized. In subsequent waves of immunization, teachers, other school staff, workers in essential industries, and people living in homeless shelters, group homes, prisons and other facilities received the vaccines.

Healthy children, young adults and everyone else would not get the first vaccines, but would be able to get them once stocks increased.

The panel of experts described a “moral imperative” to reduce the heavy burden of COVID-19 disease on blacks, Hispanics, Native Americans, and Alaska Natives, and suggested that state and local authorities could target vulnerable neighborhoods using data from the Centers for Disease Control and Prevention.

National academies will be soliciting public comments on the plan until Friday.

There is a good reason why so many COVID-19 vaccines are in development.

“The first vaccines that come out are unlikely to be the best,” said Dr. Nicole Lurie, who helped lead pandemic planning under the Obama administration, at a University of Ottawa vaccine symposium. Minnesota.

There is no guarantee that any of the main candidates will be successful – and the bar is higher than for COVID-19 treatments, as these vaccines will be given to healthy people. The final tests, experts stress, must involve a large number of people to find out if they are safe enough for mass vaccinations.

They are made in different ways, each with advantages and disadvantages. One problem: Most of the main candidates are tested with two doses, which increases the time it takes to get a response – and, if one of them works, to fully immunize people.

Another: these are all blows. Vaccine experts are closely watching the development of some nasal spray alternatives that may well begin the first stage of human testing later this year – late in the race, but likely advantageous against a virus sneaking its way down the road respiratory.

For now, here is a dashboard of vaccines that have already started or are approaching end-stage testing:


Candidates Moderna and Pfizer began Phase 3 testing at the end of July.

Neither uses the actual coronavirus. Instead, they’re made with the genetic code for the aptly named “spike” protein that covers the surface of the coronavirus. Inject the vaccine containing this code, called mRNA, and the body’s cells will produce harmless spike proteins – just enough for the immune system to respond, causing it to react if it later encounters the real virus.

These mRNA vaccines are easier and faster to manufacture than traditional vaccines, but it is a new and unproven technology.


The UK University of Oxford and AstraZeneca are making what scientists call a “viral vector” vaccine, but a good analogy is the Trojan horse. The injections are made with a harmless virus – a cold virus that normally infects chimpanzees – that carries the genetic material of the spike protein around the body. Again, the body produces advanced proteins and primers the immune system, but this is also relatively new technology.

Two possible competitors are made with different human cold viruses.

The plans made by Johnson & Johnson began the first human studies at the end of July. The company plans to begin Phase 3 testing in September with 60,000 people in the United States and elsewhere.

The Chinese government has authorized the emergency use of CanSino Biologics’ adenovirus injections in the military before any final testing.


Making vaccines by growing a pathogenic virus and then killing it is a proven approach – this is how Jonas Salk’s famous polio vaccines were made. China has three so-called “inactivated” COVID-19 vaccine candidates made this way.

Sinovac has its candidate’s final studies underway in Brazil and Indonesia. Competitor SinoPharm has announced final test plans in some other countries.

Preparing and killing the virus safely takes longer than new technology. But inactivated vaccines give the body a glimpse of the germ itself rather than that single spike protein.



Novavax makes “protein subunit” vaccines, by growing harmless copies of the coronavirus spike protein in the lab and packaging them into virus-sized nanoparticles.

There are protein-based vaccines for other diseases, so it’s not as new a technology as some of its competitors. But he only recently completed his first study; The US government’s Operation Warp Speed ​​is targeting advanced testing later this fall.


AP journalist Danica Kirka in London contributed to this report.


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