AstraZeneca (AZ) has reported preliminary data from a trial it conducted on its COVID-19 booster shot, Vaxzevria.
The results from the trial immunogenicity and safety trial, D7220C00001, reveal that the vaccine generated a higher antibody response against the Omicron variant as well as others, including Beta, Delta, Alpha, and Gamma, according to Reuters.
An increased response was seen in people who had previously been vaccinated with either Vaxzevria or an mRNA vaccine, AstraZeneca reported. They added that they would submit this data to regulators worldwide, in the wake of the current demand for booster doses.
AstraZeneca developed Vaxzevria alongside researchers from the University of Oxford, and lab studies found last month that a three-dose course of Vaxzevria was effective against Omicron. This data is the first released by the drug maker, from its trials into its booster vaccines. This adds to the growing evidence that supports a third dose of its vaccine.
Vaxzevria is made up of another virus (adenovirus) that has been modified to contain the gene for making the SARS-CoV-2 virus, which the virus needs to enter the body’s cells. Once it has been administered, the vaccine delivers the SARS-CoV-2 gene into cells into the body. The cells will use the gene to produce the spike protein. The individual’s immune system will then recognise this protein as foreign and produce antibodies in response, activating T cells to attack it.
In December 2021, a major British trial found that AstraZeneca’s shot increased antibodies when given as a booster after initial vaccination with its own shot or Pfizer’s, which is based on mRNA technology. Despite this, the study concluded that mRNA vaccines made by Pfizer and Moderna gave the biggest boost to antibodies when given as a booster dose.
"These important studies show that a third dose of Vaxzevria after two initial doses of the same vaccine, or after mRNA or inactivated vaccines, strongly boosts immunity against COVID-19," commented Oxford Vaccine Group chief Andrew Pollard.