A COVID-19 vaccine called AZD1222 being developed by AstraZeneca and the University of Oxford showed “robust immune responses” in early-stage clinical trials neutralizing antibody responses in 91 percent of the participants who received a single dose of AZD1222 and 100 percent of the participants who received the booster dose. The United States announced it secured 300 million doses of the experimental vaccine—nearly one-third of the first one billion doses the drug maker plans to produce. The U.S. Department of Health and Human Services pledged up to $1.2 billion to accelerate the program. Though these early trial results show that the vaccine induced a reaction in the body, much larger Phase III trials are still needed to determine if AZD1222 actually provides immunity to COVID-19. AstraZeneca announced that it has already concluded agreements for at least 400 million doses of AZD1222 and has the capacity to manufacture one billion doses. The company says it hopes to begin first deliveries by the end of 2020.
There are more than 160 experimental COVID-19 vaccines in development around the world but one of them, in particular, has become a leading contender in the global race to halt the spread of the coronavirus that causes the disease—SARS-CoV-2.
A COVID-19 vaccine called AZD1222 being developed by AstraZeneca and the University of Oxford triggered “robust immune responses” among participants in early-stage clinical trials. The vaccine triggered an increase in antibodies (proteins in the blood that help fight off infection) and a T-cell response. T-Cells also help the body fight disease.
The effectiveness of the experimental vaccine was assessed against a meningococcal conjugate vaccine that served as a control. Only the researchers knew which treatment the participants received.
The trials showed that neutralizing antibody responses were detected in 91 percent of the participants studied who received a single dose of AZD1222 and 100 percent of the participants who received the booster dose. A T-cell response was also induced in all of the participants studied, which was maintained two months after injection.
The Oxford vaccine uses another type of harmless virus to deliver biological instructions for how to fight off the coronavirus that causes COVID-19.
The viral vector used in the vaccine is based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein—the protein the coronavirus uses to invade people’s cells.
Recombinant vector vaccines, such as AZD1222, act like a natural infection, which means they may be particularly effective in teaching the immune system how to fight germs. After vaccination, the surface spike protein is produced, which primes the immune system to attack COVID-19 if it ever infects the body.
The virus that causes the common cold in chimpanzees was genetically modified to make it “appear” more like SARS-CoV-2—but it can’t cause infections in people.
Though these early trial results are promising and show that the vaccine induced a reaction in the body, much larger Phase III trials are still needed to determine if AZD1222 actually provides immunity to COVID-19.
Phase III trials are already underway in the U.K., the United States, Brazil and South Africa.
AstraZeneca announced, meanwhile, that it has already concluded agreements for at least 400 million doses of AZD1222 and has the capacity to manufacture one billion doses. The company says it hopes to begin first deliveries by the end of 2020.
Back on May 21, the United States announced it secured 300 million doses of the experimental vaccine—nearly one-third of the first one billion doses the drug maker plans to produce.
The U.S. Department of Health and Human Services secured the vaccines by pledging up to $1.2 billion to accelerate the drug maker’s vaccine development program.
FULL STORY. Link: https://www.sharecare.com/health/coronavirus/article/oxford-coronavirus-vaccine-shows-promise
BACKGROUND:
Link: https://www.sharecare.com/health/coronavirus/article/oxford-coronavirus-vaccine-shows-promise
Author: Mary Elizabeth Dallas, Senior Editor
Publisher: Sharecare (www.sharecare.com)
Published: July 21st 2020
Tags: COVID, AstraZeneca, robust immune responses, Oxford University