Oxford-AstraZeneca Covid Vaccine Elicits Dual Immune Action

United Kingdom (Bloomberg) — A coronavirus vaccine the University of Oxford is developing with AstraZeneca Plc displayed highly encouraging results in early human testing, a sign of progress in the high-stakes pursuit of a shot to defeat the pathogen.

Early results of a closely watched Phase 1/2 trial published in The Lancet shows evidence that the vaccine ca produce immune responses that would be expected to protect people against the infection and also appear to be safe.

The Oxford vaccine prompted a neutralizing antibody response withing 28 days and immune T-cell response within. 14 days, according to the study organizers.  Neutralizing antibodies — so-called because they can neutralize the virus — were detected in most participants after one shot, and in all of them after two.The results are a key milestone for one of the fastest-moving vaccine projects globally.

“The immune system has two ways of finding and attacking pathogens — antibody and T cell responses. This vaccine is intended to induce both, so it can attack the virus when it’s circulating in the body, as well as attacking infected cells.”

University of Oxford pediatrician Dr. Andrew Pollard, the study’s lead author

The researcher hopes that the vaccine can protect people for an extended period and recommends further research to confirm that the vaccine effectively protects against SARS-CoV-2 infection, and for how long any protection lasts.

“Our hope is that we can actually start delivering a vaccine before the end of the year,” AstraZeneca Chief Executive Officer Pascal Soriot said on a call with Bloomberg. “We’re working as quickly as we can but of course there are things you cannot control.”

The vaccine trial included 1,077 people age 18 to 55 with no history of COVID-19 infection and took place in five UK hospitals from late April to late May. Participants received the Covid-19 vaccine or a meningitis vaccine.

There were no serious adverse events related to the vaccine; fatigue and headache were the most commonly reported side effects. Other common reactions included pain at the injection site, muscle ache, malaise, chills, feeling feverish and high temperature.

A positive outcome had been widely expected after reports last week lifted the stock, with the vaccine already in more advanced trials. According to Bloomberg, researchers plan to prioritize testing a two-dose regimen, rather than a single shot, dampening some of the enthusiasm over the vaccine, which they’ve previously said they hoped to deliver as early as September.

READ: Stocks In the Time of Pandemic

Other vaccine projects published in the medical journal The Lancet including shots being developed by China’s CanSino Biologics Inc., in partnership with Pfizer Inc. and BioNTech SE also delivered positive trial updates Monday.

The results, according to Bloomberg, boost optimism about ways to counter a pandemic that’s killed more than 600,000 people and triggered economic turmoil worldwide. 

Moderna Inc., another front-runner, released results last week from an early-stage test that showed its vaccine raised levels of antibodies that fight the virus.

The results, according to Bloomberg, boost optimism about ways to counter a pandemic that’s killed more than 600,000 people and triggered economic turmoil worldwide. Moderna Inc., another front-runner, released results last week from an early-stage test that showed its vaccine raised levels of antibodies that fight the virus.

“The market should be extremely gratified that we have several vaccine candidates that are making good progress,” Lancet Editor Richard Horton said in an interview with Bloomberg Television.

Moderna Therapeutics
Source: Brian Snyder/Reuters

Key Step

Although stimulating production of neutralizing antibodies doesn’t prove a vaccine will be effective, it’s considered an important early step in testing. Dr. Eric Topol stressed that Phase 1/2 vaccine trials aren’t intended to show prevention of infection/disease. According to the researcher, these important efforts are are doing precisely what they are designed to do: test the immune response in people and get a sense about safety.

The Phase 1 human trial of a single dose of Oxford vaccine resulted in a four-fold increase in antibodies to the virus’s spike protein in 95% of participants one month after injection, AstraZeneca said in a statement. SARS-CoV-2 uses the spike protein to enter cells. A T-cell response was induced in all participants who got the vaccine, peaking by day 14 after injection.

“The vaccine worked and developed the all-important neutralizing antibodies, in most cases after one shot and in all cases after 2 shots,”

Ian Jones, professor of biomedical sciences at the University of Reading.

Across the world, about 160 coronavirus vaccines are in various stages of development, according to the World Health Organization. With the Oxford shot as the front-runner, as it has already begun final-stage tests, AstraZeneca has said it may begin delivering doses to the U.K. as early as September.

AstraZeneca received a boost when the U.S. pledged as much as $1.2 billion toward development. Under its agreement with the British drugmaker, the U.S. could begin receiving supplies as early as October.

Covid Fight

Companies and universities are relying on an array of approaches in the fight against Covid-19. Bloomberg reported that the Oxford team has developed a technology that can speed up the process by using a harmless virus to carry some of the pathogen’s genetic material into cells to generate an immune response. The proposed vaccine is made from a weakened version of a common cold virus that’s genetically changed to make it unable to grow in humans.

US pharmaceutical company Pfizer and German biotechnology company BioNTech reported their Covid-19 vaccine candidate elicited a “robust” antibody and T-cell immune responses in an early Phase 1/2 study.

“The preliminary data indicate that our mRNA-based vaccine was able to stimulate antibody as well as T-cell responses at remarkably low dose levels…We believe both may play an important role in achieving effective clearance of a pathogen such as SARS-CoV-2.”

Dr. Özlem Türeci, chief medical officer and co-founder of BioNTech

According to BioNTech and Pfizer, a Phase 3 vaccine trial that might involve up to 30,000 healthy participants is expected to begin in late July, if it receives regulatory approval.


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