Scientists to test combination of Oxford-AstraZeneca and Russian vaccines

ASTRAZENECA MUST join a trial exploring whether a combination of its Covid-19 vaccine candidate and the Russian Sputnik V vaccine can offer better protection against coronavirus.

The pharmaceutical giant, which is developing the AZD1222 vaccine with the University of Oxford, said it would collaborate with the Russian Gamaleya Research Institute.

The trials will involve people over the age of 18, AstraZeneca said on Friday.

They will help investigate the possibility of a combination of two vaccines that boost the immune response of recipients to Covid-19.

The Oxford-AstraZeneca vaccine has not yet been approved for use in the UK, and the country’s drug regulator, the Medicines and Healthcare Products Regulatory Agency (MHRA) is still reviewing the data from the trials.

Sputnik V, which is currently available to Russians in high-risk groups, received regulatory approval from the Russian government in early August amid criticism after being tested on several dozen people.

Both injections are adenoviral vector vaccines that contain genetic material from the protein spike of Sars-Cov-2, the virus that causes Covid-19.

These types of vaccines are based on weakened versions of adenoviruses, which are a group of viruses that generally infect the membranes of the eyes, respiratory tract, urinary tract, intestines, and nervous system, and include the common cold.

They are a different kind of injection to the Pfizer / BioNTech vaccine being launched in the UK, which uses mRNA technology that tricks the body into producing some of the viral proteins.

AstraZeneca said it was considering how to evaluate “heterologous combinations of different vaccines.”

The drug company explained that vaccines often require more than one dose, an initial “prime” followed by a “boost.”

This can be done by administering the same jab multiple times, known as a “homologous boost”, or by combining different vaccines targeting the same antigen, known as a “heterologous boost.”

AstraZeneca said it was “working with industry partners, governments and research institutions around the world, and will soon begin exploring with the Gamaleya Research Institute in Russia to understand whether two adenovirus-based vaccines can be successfully combined.”

The UK has obtained 100 million doses of the Oxford-AstraZeneca vaccine.

The published provisional phase three results of the vaccine trials found that jab protects against symptomatic disease in 70% of cases, with an efficacy of 62% for those who received two full doses and 90% for those who received two full doses. they received half and then a full dose.

Dr Stephen Griffin, Associate Professor at the University of Leeds School of Medicine, explained that adenovirus vaccines can become “victims of their own success” after a first dose because they trigger an “anti-vector” response in the body. which reduces the effectiveness of a second jab.

He said this could be a factor in the Oxford-AstraZeneca vaccine showing less efficacy at a higher dose.

Dr. Griffin said: “Although our immune system has not seen chimpanzee adenovirus before, the first observation at the highest dose potentially generates sufficient responses to lessen the effect of the second boost.

“The Sputnik vaccine avoids this problem by using two different human adenoviruses for the first and second injections, which means that the anti-vector response is much less likely to have a negative impact.

“Therefore, combinations of these vaccines will give more flexibility in terms of regimens in the future, and it is also encouraging to learn that adenovirus and RNA vaccine combinations are planned.

“The importance of a second injection should not be underestimated, as it is important for the longevity, specificity and efficacy of response to most vaccines.”