See how some of the major coronavirus vaccines work

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

Two vaccines are already authorized by the FDA and Europe and three are authorized in the United Kingdom. See how some of the major coronavirus vaccines and candidate vaccines work.

Pfizer and its German partner BioNTech use a new approach to making vaccines that use messenger RNA or mRNA.

This project was chosen for a pandemic vaccine years ago because it lends itself to rapid recovery. All that is needed is the genetic sequence of the virus that is causing the pandemic. Vaccine manufacturers don’t even need the virus itself – just the sequence.

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

Messenger RNA is a simple strand of genetic code that cells can “read” and use to make a protein. In the case of this vaccine, mRNA instructs muscle cells in the arm to manufacture the specific piece of the virus’s spine protein. Then the immune system sees it, recognizes it as strange and is prepared to attack when a real infection occurs.

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

“It takes 25 different coronavirus proteins to make a coronavirus, so there is no concern about the RNA that is producing a virus.”

Pfizer's Covid-19 vaccine appears to work against the mutation in new strains of coronavirus.

Clinical trials have shown that the Pfizer vaccine was 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 is wrapped in lipid nanoparticles – a coating of a buttery substance that can melt at room temperature. That is why the Pfizer vaccine should be kept at ultracold temperatures of around 100 degrees F (minus 75 degrees C). This means that special equipment is needed to transport and store this vaccine.

The Pfizer vaccine won the US FDA in December and is being delivered to millions of people in the United States and the United Kingdom. The United States government has signed a contract to purchase 200 million doses of the Pfizer coronavirus vaccine.

Side effects are rare and generally mild. They include fever and headache, although very few people have experienced allergic reactions to the vaccine. It is unclear what causes the allergic reaction, and the FDA and the US 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 encodes cells to make a piece of the peak protein. That was a careful choice – scientists had to choose a piece of the virus that they thought would not mutate, or change much, over time. The virus uses the spike protein to grab the cells it attacks and the structure appears to remain stable for generation after generation of viral replication.

Like the Pfizer vaccine, the Modern vaccine goes to muscle cells in the arm, and perhaps to nearby immune cells, and instructs them to make pieces of spike protein.

Clinical trials have shown that Moderna’s vaccine was 94% effective in preventing symptomatic infections and the company claims to have data showing that the vaccine also prevents all infections, including those that do not cause symptoms.

Moderna believes its vaccine will protect against coronavirus for at least one year

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

The FDA authorized Moderna’s vaccine in December and the United States contracted 200 million doses of Moderna’s vaccine.

Janssen Pharmaceuticals, vaccine arm of Johnson & Johnson

Janssen’s coronavirus vaccine is a recombinant vector vaccine. He uses a genetically modified version of adenovirus 26, which can cause the common cold, but genetic adjustments have disabled it. It also provides the genetic instructions for making a piece of protein spike.

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

Johnson & Johnson's coronavirus vaccine generates immune response, few side effects, in the first tests

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

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

AstraZeneca

The AstraZeneca vaccine, made by a team at Britain’s Oxford University, is called a vector vaccine. It uses a common cold virus called adenovirus to transport the coronavirus protein to cells.

It also aims to make people’s bodies produce their own vaccines, producing small copies of the protein spike, but the method of administration is different. This adenovirus infects chimpanzees, but does not make people sick. It was modified to not replicate – and then genetically modified to inject cells with the DNA that codes for the coronavirus spike protein.

The Covid-19 vaccine cannot be safe and other myths

It is a cheaper way to make vaccines – but slower than using RNA. The company has pledged to make its vaccine available economically to countries around the world. The vaccine can be kept stable for six months at normal refrigerator temperatures, the company said.

It is approved in Britain, but the US FDA is awaiting test data in the USA. Confusing test data indicated that the AstraZeneca vaccine may be 70% effective on average.

Novavax

Novavax, a biotechnology company based in Maryland, 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.

This is also a tried and tested vaccine approach. A hepatitis B vaccine given to newborns is a protein subunit vaccine, as is the human papillomavirus or vaccine against HPV and FluBlok, the vaccine against influenza from Sanofi.

Novavax uses an insect virus called baculovirus to obtain the coronavirus spike protein in the moth’s cells, which then produce the protein. This is harvested and mixed with an adjuvant – an immune booster – based on saponin, found in soap bark trees.

Sanofi and GlaxoSmithKline

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

Phase 1/2 tests showed that the vaccine induces an immune response comparable to patients who recovered from Covid-19 in young adults, but the vaccine did not produce the desired immune response in older adults. The companies plan to launch a new test 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 Sputnik V coronavirus vaccine is an adenoviral vector vaccine. It uses two common cold viruses called adenovirus 5 and adenovirus 26 to transport the genetic material for the spike protein to the body.

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