A combined approach to COVID-19 vaccines could provide logistical and immunological benefits


WAlthough it is now quite easy to get a COVID-19 in most places in the US, vaccine implementation in other parts of the world has been slow or inconsistent due to scarcity, unequal access i security concerns.

Researchers hope that a combined approach to COVID-19 vaccines will help alleviate these problems and generate more flexibility in vaccination regimens available to people.

Around the world, different pharmaceutical companies have adopted different approaches to developing vaccines. Pfizer-BioNTech and Modern created MRNA vaccines. Oxford-AstraZeneca and Johnson & Johnson went with what is called viral vectors. The Novavax COVID-19 vaccine is protein-based.

Therefore, mixing vaccines could mean something more than changing manufacturers, such as Pfizer for the first dose to Moderna for the second dose. You may be taking advantage of a file a different way to stimulate your immune response if you opt for a first dose of AstraZeneca and a second dose of Moderna.

The most obvious advantages of treating various brands and types of COVID-19 vaccines as interchangeable are logistics – People can get any available shot without worries. Accelerating the global launch of vaccination, mixing and combining vaccines could help end this pandemic. Researchers also expect the combination of different vaccines to trigger one more robust and longer lasting immune response compared to receiving both doses of a single vaccine. This approach can better protect people from emerging variants.

Biological effects of a mix-and-match approach

Scientists suspect that there are some ways to receive two different COVID-19 vaccines it can trigger a stronger immune response.

Each company used it lightly different regions of the SARS-CoV-2 ear protein in their formulations. It is the ear protein of the virus to which your immune system responds, so exposure to different portions of the ear protein should mean that your body will form a series of corresponding antibodies that can defend against future infection. The range of antibodies should provide better protection and increase the likelihood that you are protected from variants with spike protein changes.

And different vaccine technologies activate unique aspects of the immune system thanks to how they present their portion of ear protein.

He Pfizer i Modern Vaccines consist of a small fragment of mRNA, a genetic material contained in the recipe to form a region of the SARS-CoV-2 ear protein. Wrapped in a layer of fat, the mRNA slips into the cells of a vaccinated person where it directs the production of the viral protein. The person’s immune system then recognizes the strange ear protein and produces antibodies against it.

Several other COVID-19 vaccines are based on one viral vector. In these cases, researchers modified an adenovirus that usually causes the common cold to deliver DNA instructions to produce a portion of the SARS-CoV-2 ear protein. The modified virus is safe because it cannot replicate in people. Along with J&J i D’AstraZeneca, includes examples of COVID-19 viral vector vaccines used worldwide Sputnik Vand the Vaccine CanSino Biologics.

Your immune system can develop a immune response to the viral vector vaccine itself, which could reduce the effectiveness of the coronavirus vaccine. Experts expect the combination of vaccine platforms, for example, using an mRNA-based vaccine or to include a different viral vector for the second dose, could reduce this risk.

Investigate the safety and effectiveness of combos

All over the world, studies are underway in animals and people to investigate safety, the types of immune response generated, and how long the immunity lasts when a person receives two different COVID-19 vaccines.

Results of a Spanish trial of more than 600 people indicated that vaccination with both the AstraZeneca viral vector and mRNA-based Pfizer-BioNTech COVID-19 vaccines triggers a strong immune response against the SARS-CoV-2 virus.

Preliminary results a German study which has not yet been reviewed by experts, found that obtaining the AstraZeneca vaccine for the first time followed by the Pfizer vaccine resulted in the production of more protective antibodies and provided better protection against worrisome variants compared to two doses of AstraZeneca.

The Com-VOC study in the UK the safety and efficacy of giving patients a combination of AstraZeneca and Pfizer-BioNTech intakes is also being investigated. Preliminary conclusions indicate that people who received a shot of each type were more likely to report mild to moderate side effects than those who received two doses of the same vaccine. The final results of this study, including the effectiveness of this approach, are expected in June 2021. The extended study of Com-CoV2 is testing other combinations of COVID-19 vaccines, specifically the Moderna mRNA platform and the Novavax protein platform.

Combos could be a good anti-variant strategy

Emerging variants of coronavirus are one of the more intriguing reasons consider mixing vaccines. The administration of vaccines targeting different variants would provide broad collective immunity and limit the emergence of possibly more dangerous new strains.

People who are fully vaccinated may need a third shot to address genetic differences in new variants. Switching platforms for this reinforcing trait (e.g., if your first round was based on a viral vector, switching to mRNA, or protein-based) could help boost your immune response.

Influenza vaccines routinely protect against multiple strains of influenza virus – but they are usually made by the same company. In the future, this approach could lead to vaccines containing several regions of SARS-CoV-2 to protect against various variants, or regions of both coronavirus and influenza proteins, protecting against both viruses in one. taken away.

What is allowed so far?

For now, however, the U.S. Centers for Disease Control and Prevention only allows Pfizer and Moderna mRNA-based plans to be mixed into “exceptional situations“, Such as a limited supply of vaccines or if a patient does not know which vaccine they originally received.

The Public Health Agency of Canada has recently approved the mixture of different COVID-19 vaccines if the limited supply prevents someone from getting their second dose of the same vaccine, or if anyone is afraid of a second dose of AstraZeneca due to advertising side effects.

EU countries are so far pending further study results before allowing vaccine doses to be mixed.

Maureen Ferran, Associate Professor of Biology, Rochester Institute of Technology

This article is republished from The conversation under a Creative Commons license. Read the original article.

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