Trials of variant-tweaked jab offer hope
Researchers in the United Kingdom are testing a new version of the COVID-19 vaccine from Oxford University and AstraZeneca that has been altered in order to provide better protection against variants of the novel coronavirus.
The new vaccine, called AZD2816, is closely based on the original AstraZeneca jab, with minor genetic alterations in order to increase efficacy against the Beta strain of the virus that was first identified in South Africa.
Oxford researchers say that other variants share some of the same mutations seen in Beta, so AZD2816 could provide protection against multiple strains.
Late-stage trials for the new jab started on Sunday, when the first of an eventual 2,250 participants in the UK, South Africa, Brazil and Poland received doses.
Researchers are initially testing the shot as a booster among participants who have already received a full course of the original AstraZeneca jab or an mRNA treatment, and further testing on unvaccinated people will follow.
“It is important we continue to stay ahead of genetically distinct variants of the coronavirus,” said Mene Pangalos, who is executive vice-president of biopharmaceutical research and development at AstraZeneca.
Results from the study should come through toward the end of the year.
Genetic information
The AstraZeneca vaccine works by delivering a harmless virus, called a viral vector, into the body’s cells. The vector contains genetic information that instructs cells to produce the spike protein found on the surface of the novel coronavirus. This familiarizes the immune system with the spike protein, so the body can react and neutralize the virus before infection takes hold.
Over the course of the pandemic, the coronavirus has evolved into a variety of strains, many of which have mutations to the spike protein. Some of these changes have made variants more infectious, and some mean that original vaccines are less effective at priming the immune system against a viral invasion.
Researchers at Oxford identified 10 mutations on the spike protein of the Beta variant, and adjusted the genetic instructions contained within the AZD2816 viral vectors accordingly. Many of the mutations in the Beta strain are seen in other so-called variants of concern, the researchers said, so the new jab could provide increased efficacy against other forms of the virus.
“Testing booster doses of existing vaccines and new variant vaccines is important to ensure we are best prepared to stay ahead of the coronavirus pandemic, should their use be needed,” said Andrew Pollard, the director of the Oxford Vaccine Group.