Scientists are testing a new Covid-19 vaccine question: Mixing different doses

Finding ways to strengthen the body ‘s defenses has led to a new crisis following the emergence of changes in the virus, whose sensitivity to existing images is not well understood. .

Researchers said the mix-and-match approach, if proven in human trials, will bring another benefit as countries race to protect their citizens: it may help to reduce the pressure. increase vaccine supply by giving doctors more options when patients are expecting a second dose.

“You may know that you can mix different types of vaccines depending on the availability of supply just by speeding up vaccination efforts,” said Helen Fletcher, professor of vaccination at the London School of Hygiene and Tropical Medicine.

Researchers at Oxford University are enrolling volunteers in an 820-person test in the UK to evaluate a one-two combination of the image developed by Pfizer Inc.

and BioNTech BNTX in Germany 2.84%

SE and the vaccine developed by Oxford University and AstraZeneca PLC. The trial, part-funded by the UK government, was announced by the UK Department of Health and Social Care on Thursday.

AstraZeneca said in December that it intends to test its immunization with Sputnik V, the vaccine developed in Russia, in a human lawsuit.

Immunologists said the mix-and-match strategy is a tried-and-tested method to boost the body’s immune response to relapse. A heterologous primary stimulant vaccine has been developed against other infectious diseases, including ebola, malaria and tuberculosis, and has been used to sharpen the body’s attack against pathogens that cause some infections. cancers and against the tumors themselves.

“I don’t see any negative impact on major heterologous stimuli,” said Brian Lichty, associate professor of epidemiology and molecular medicine at McMaster University in Hamilton, Ontario.

By combining images that can train the immune system to recognize and attack a pathogen in different ways, the body could gather a larger or more equipped weapon to attack any invaders. whatever it meets, according to researchers. The combination strategy could avoid the risk of a traditional two-vaccine vaccine that the immune system will reintroduce the vaccine a second time.

Russia’s Sputnik V follows the mix-and-match idea by using different viral behaviors to train the immune system against Covid-19 in each of its two doses.

The UK test is the first to test against Covid-19 a mix-and-maids approach using different technologies. Pfizer and BioNTech vaccines rely on molecular messengers called messenger RNA to direct remodeling to cells. AstraZeneca’s uses a modified chimpanzee virus as a vector to deliver its payment burden.

Ugur Sahin, chief executive of BioNTech, said in December he opposed such a test, saying there was a lack of data on the safety and efficacy of Covid-19 vaccines. A study like this “uses up doses that could make people who need them profitable,” he said. “I’m not happy about this.”

Pfizer said in a statement that it recommends using its vaccine in a way that is supported by existing test data but said decisions about other dosing programs remain with health authorities. AstraZeneca said it is helpful of the tests.

Immunologists said a combination of technologies is not uncommon. Scientists at Oxford University in January in a study awaiting revision reported that the different vaccine-based RNA and viral-vector vaccine produced a stronger immune response in mice. Messenger RNA vaccines have been tested in combination with viral-vector vaccines in cancer types.

The aim of the UK test is to test whether a mix-and-match approach works as well as or better than normal practice, said Matthew Snape, associate professor of pediatrics and vaccines at Oxford and director the test.

Some participants get a glimpse of AstraZeneca first with the Pfizer firing in second place. Others will get behind. Control groups receive the standard two-dose record of a single vaccine. The trial will also look at the range of views over both four and 12 weeks. Preliminary results are expected in late May or early June, and participants will be closely monitored for side effects. The plan is to enroll more volunteers and try a new mix as more vaccines gain regulatory approval in the UK, Dr. Snape said.

Researchers regularly test participants’ blood for antibodies, disease-fighting T cells and other signs of immune system activity. They will compare those on the mixed regimen and those on the regular dosing system to find any differences. Prof. Snape said researchers will be able to use these samples to gauge the effectiveness of combination-and-maids vaccines against coronavirus changes that may not be as vulnerable to normal observations.

Mary Ramsay, head of vaccination at Public Health England, a UK health organization, said success in the trial could help doctors involved in bottling vaccine supply. A mix-and-match strategy might help if, for example, someone is unable to get a second dose of the original picture or a poor response to the first one.

“It really makes the implementation a lot simpler,” she said.

Mene Pangalos, AstraZeneca’s executive vice president for biopharmaceuticals research and development, said at a press conference Wednesday: “Ultimately, we want to understand the interoperability of these vaccines. These are important questions, because eventually, people use different vaccines at different times. “

– Jenny Strasburg and Bojan Pancevski contributed to this article.

Write to Jason Douglas at [email protected]