Here’s how some of the top coronavirus vaccines work

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If they are positive, the company plans to seek emergency use authorization from the United States Food and Drug Administration and make the vaccine available to the public.

Two vaccines already have FDA and European authorization and three are authorized in the UK. Here’s how some of the best coronavirus vaccines and vaccine candidates work.

Pfizer and its Germany-based partner BioNTech are using a new approach to make vaccines that use messenger RNA or mRNA.

This design was chosen for a pandemic vaccine years ago because it lends itself to rapid turnover. All it takes is the genetic sequence of the virus that caused the pandemic. Vaccine makers don’t even need the virus itself – just the sequence.

In this case, researchers at BioNTech used a small piece of genetic material encoding a piece of the spike protein – the structure that adorns the surface of the coronavirus, giving it that studded appearance.

Messenger RNA is a single strand of genetic code that cells can “read” and use to make a protein. In the case of this vaccine, the mRNA instructs the muscle cells in the arm to make the particular piece of the virus spike protein. Then the immune system sees it, recognizes it as a stranger, and is ready to attack if there is a real infection.

“RNA is like Snapchat messages that expire. RNA vaccines do NOT become a permanent part of your body. They are temporary messages asking cells to temporarily make a viral protein,” said Shane Crotty, virologist at the La Jolla Institute of Immunology Twitter.

“It takes 25 different coronavirus proteins to make a coronavirus, so there is no need for the RNA to make a virus.”

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Clinical trials have shown Pfizer’s vaccine to be 95% effective in preventing symptomatic infections. Pfizer is working to show that the vaccine can prevent all infections, including those that do not cause symptoms.

MRNA is very fragile, so it’s enclosed in lipid nanoparticles – a coating of a buttery substance that can melt at room temperature. This is why Pfizer’s vaccine should be stored at ultra-cold temperatures of about minus 100 degrees F (minus 75 degrees C). This means that special equipment is needed to transport and store this vaccine.

Pfizer’s vaccine won the EUA from the FDA in December and is being shipped to millions of people in the US and UK. The US government has pledged to purchase 200 million doses of Pfizer’s coronavirus vaccine.

Side effects are rare and usually mild. They include fever and headache, although very few people have had allergic reactions to the vaccine. It is not known what causes the allergic reaction, and the FDA and the United States Centers for Disease Control and Prevention are investigating.

Modern

Moderna’s vaccine is also based on mRNA. “MRNA is like software for the cell,” Moderna said on its website.

And like the Pfizer / BioNTech vaccine, it codes for cells to make a piece of the spike protein. It was a prudent choice – scientists had to choose a piece of the virus that they believed wouldn’t mutate or change much over time. The virus uses the spike protein to attack the cells it attacks and the structure appears to remain stable from generation to generation of viral replication.

Like Pfizer’s vaccine, Moderna’s vaccine enters muscle cells in the arm, and possibly neighboring immune system cells, and instructs them to make advanced pieces of protein.

Clinical trials have shown Moderna’s vaccine to be 94% effective in preventing symptomatic infections, and the company says it has data showing that the vaccine also prevents all infections, including those that don’t cause symptoms.

Moderna believes his vaccine will protect against coronavirus for at least a year

Moderna has developed a different formulation for lipid nanoparticles in order to protect the mRNA of its vaccine. These formulations are company secrets, but Moderna thinks their approach is better and said their vaccine can be shipped at minus 20 degrees C (minus 4 degrees F) and can be kept stable for 30 days between 2 degrees and 8. degrees C (36 to 46F). ), the temperature of a standard household refrigerator.

The FDA cleared Moderna’s vaccine in December and the United States signed a contract for 200 million doses of Moderna’s vaccine.

The vaccine arm of Johnson & Johnson Janssen Pharmaceuticals

The Janssen coronavirus vaccine is a recombinant vector vaccine. It uses a genetically engineered version of adenovirus 26, which can cause the common cold, but gene tinkering has turned it off. It also provides the genetic instructions for making a piece of advanced protein.

It is a vaccine that has already been tested on the market. The adenovirus 26 vector was used to make the company’s Ebola vaccine, which received marketing authorization from the European Commission in July.

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It is a single dose vaccine. Data from the phase 1-2 trial published in the New England Journal of Medicine this week shows the vaccine generated an antibody response in volunteers aged 18 to 55 as well as a second batch of volunteers aged 65 and more. The side effects were minimal.

The company is also testing a two-dose regimen in volunteers to see if adding a second dose provides better protection or longer lasting protection.

AstraZeneca

AstraZeneca’s vaccine, made with a team from the UK University of Oxford, is called a vector vaccine. It uses a cold virus called adenovirus to transport the coronavirus spike protein into cells.

It also aims to make the human body produce its own vaccines by producing small copies of advanced proteins, but the method of administration is different. This adenovirus infects chimpanzees but does not make people sick. It was engineered to not replicate – then genetically engineered to inject cells with DNA encoding the full length coronavirus spike protein.

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It’s a cheaper way to make vaccines – but slower than using RNA. The company is committed to making its vaccine inexpensively available in countries around the world. The vaccine can be kept stable for six months at standard refrigerator temperatures, the company said.

It is approved in Britain but the US FDA is awaiting US test data. Confusing data from trials indicates that AstraZeneca’s vaccine may be 70% effective on average.

Novavax

Novavax, a Maryland-based biotechnology company, specializes in “protein subunit” vaccines. They use virus-like nanoparticles as a base and cover them with genetically modified pieces of the coronavirus spike protein.

It is also a proven vaccine approach. A hepatitis B vaccine given to newborns is a protein subunit vaccine, just like the human papillomavirus or HPV vaccine and FluBlok, the influenza vaccine from Sanofi.

Novavax uses an insect virus called baculovirus to get the coronavirus spike protein into butterfly cells, which then produce the protein. This is harvested and mixed with an adjuvant – an immune booster – made from saponin, found in soap bark trees.

Sanofi and GlaxoSmithKline

It is also a protein subunit vaccine, using Sanofi’s FluBlok technology with adjuvant GlaxoSmithKline. It also uses a baculovirus to grow small chunks of peak protein.

Phase 1/2 trials showed that the vaccine induces an immune response comparable to that of patients who recovered from Covid-19 in young adults, but the vaccine did not produce the desired immune response in adults more aged. The companies plan to launch a new trial in February.

Sinovac and Sinopharm

CoronaVac from Chinese company Sinovac uses an inactivated virus – one of the oldest methods of vaccinating people. Whole batches of coronavirus are grown, “killed” and then made into a vaccine. Likewise, the Sinopharm vaccine in an inactivated virus.

Sputnik V

The Russian vaccine against the Sputnik V coronavirus is an adenoviral vector vaccine. It uses two common cold viruses called adenovirus 5 and adenovirus 26 to carry the genetic material for the spike protein around the body.

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