Pharmaceutical giant AstraZeneca is one of many drug companies participating in the race to a COVID-19 vaccine. Its experimental vaccine, known as AZD1222, was recently tested in pigs with positive results.
About AZD1222 Vaccine
Also known as the ChAdOx1 nCoV-19 vaccine, AZD1222 was developed by Oxford University scientists who are now working directly with AstraZeneca on development and production. It’s formulated with a weakened version of a common cold virus that has been genetically changed to make it impossible to grow in humans.
The AZD1222 construct also contains added genetic material, which is used to make proteins from the SARS-CoV-2 coronavirus called Spike glycoprotein. This protein exists on the surface of the virus and plays a critical role in the infection pathway of the coronavirus.
After vaccination with AZD1222, the surface spike protein is produced to prime the immune system to attack the first signs of COVID-19 if it ever infects the body. As a result, scientists hope that vaccination with AZD1222 will stop the coronavirus from entering human cells and ultimately prevent infection.
Oxford University Performing Phase 2/3 Clinical Trial
Oxford University initiated the first clinical trials with AZD1222 by testing it in more than 10,000 healthy adults and children. Phase 2 extended to include a small number of older adults aged 56-69 and over 70. Researchers are sessing the immune response to the vaccine in people of different ages to determine if there’s a variation in how well the immune system responds.
Professor Andrew Pollard, head of the Oxford Vaccine Group, said, “The clinical studies are progressing very well and we are now initiating studies to evaluate how well the vaccine induces immune responses in older adults, and to test whether it can provide protection in the wider population.”
Adult participants in both Phase 2 and 3 of Oxford University’s trial will be randomized to receive one or two doses of either AZD1222 or MenACWY, a control comparison currently used in the UK to immunize against meningococcus.
Double Dose Triggers Stronger Immune Response
As Oxford University continues its research, Britain’s Pirbright Institute recently released research showing that giving pigs an initial prime dose of AstraZeneca’s experimental vaccine, followed by a booster dose of the vaccine, elicited a stronger immune response than just a single dose.
“The researchers saw a marked increase in neutralising antibodies, which bind to the virus in a way that blocks infection,” the Pirbright team said in a statement.
However, the response in the human body still needs to be explored further. This makes the impending results of Oxford University’s Phase 2/3 trial all the more significant in identifying the true potential of AstraZeneca’s experimental vaccine.