Here is how some of the leading coronavirus vaccines work

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

A few years ago, this design was chosen as a pandemic vaccine because it is easy to turn around quickly. All that is needed is the genetic sequence of the virus that caused the pandemic. Vaccine manufacturers don’t even need the virus itself, just the sequence.

In this case, BioNTech researchers used a small portion of genetic material to encode a spike protein that modifies the surface of the coronavirus to make it appear to be spotted.

Messenger RNA is a single strand of the genetic code that cells can “read”

; and use to make proteins. For this vaccine, mRNA instructs muscle cells in the arm to produce specific fragments of the virus’s spike protein. The immune system then sees it, recognizes it as a foreign body, and prepares to attack when the actual infection occurs.

Shane Crotty, a virologist at the La Jolla Institute of Immunology, said: “RNA is like the message of a glove that has disappeared. RNA vaccines will not become a permanent part of the human body. They are temporary messages that instruct cells to temporarily produce a viral protein. .”Twitter.

“The creation of coronavirus requires 25 different coronavirus proteins, so there is no need to worry about RNA producing viruses.”

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

MRNA is very fragile, so it is encapsulated in lipid nanoparticles-a coating of butter-like substance that can melt at room temperature. This is why Pfizer’s vaccine must be kept at an ultra-cold temperature of approximately minus 100 degrees Fahrenheit (minus 75 degrees Celsius). This means that special equipment is needed to transport and store this vaccine.

Pfizer’s vaccine was approved by the FDA EUA in December and is currently being provided to millions of people in the United States and the United Kingdom. The US government has signed a contract to purchase 200 million doses of Pfizer’s coronavirus vaccine.

modern

Like the Pfizer/BioNTech vaccine, it encodes cells to make fragments of the spike protein. This is a careful choice-scientists must choose a virus that they believe will not mutate or change significantly over time. The virus uses a spike protein to capture the cells it attacks, and the structure seems to remain stable throughout the process of virus replication.

Like Pfizer’s vaccine, the modern vaccine also enters the muscle cells of the arm, and even the nearby immune system cells, and instructs them to produce spike protein fragments.

Clinical trials have shown that Moderna’s vaccine is 94% effective in preventing symptomatic infections. The company said that data shows that the vaccine can also prevent all infections, including those that do not cause symptoms.

Moderna proposed another formulation for lipid nanoparticles to protect the mRNA in its vaccine. These formulas are confidential to the company, but Moderna believes its method is better and stated that its vaccine can be transported at minus 20 degrees Celsius (minus 4 degrees Celsius) and can be maintained at a temperature of 2 to 8 degrees Celsius (36 to 46F) Stable for 30 days), the temperature of a standard household refrigerator.

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

Johnson Pharmaceuticals

This is a vaccine that has been tested on the market before. The adenovirus 26 vector is used to manufacture the company’s Ebola vaccine, which was approved for sale by the European Commission in July.

This is a dose of vaccine. Data from Phase 1-2 trials published this week in the New England Journal of Medicine showed that the vaccine produced an antibody response in volunteers aged 18 to 55 and a second batch of volunteers 65 years and older. The side effects are minimal.

The company is also testing a two-dose treatment regimen in volunteers to see whether adding a second dose can provide better protection or longer-lasting protection.

AstraZeneca

The AstraZeneca vaccine produced by a team at the University of Oxford in the UK is called a carrier vaccine. It uses a common cold virus called adenovirus to carry the spike protein from the coronavirus into the cell.

It also aims to make the human body produce its own vaccine by stirring a small amount of spike protein, but the delivery method is different. This adenovirus can infect chimpanzees, but it does not make people sick. It was modified so that it would not replicate itself-and then genetically engineered to inject DNA encoding a complete coronavirus spike protein into the cell.

It has been approved in the UK, but the US FDA is waiting for data from the US trial. Confusing test data shows that AstraZeneca’s vaccine has an average effective rate of 70%.

Novax

Novavax, a biotechnology company based in Maryland, specializes in “protein subunit” vaccines. They are based on virus-like nanoparticles and genetically modified the coronavirus spike protein.

This is also a real vaccine method that has been tested in practice. The hepatitis B vaccine used by newborns is a protein subunit vaccine, as is the human papillomavirus or HPV vaccine and Sanofi’s flu vaccine FluBlok.

Novavax uses an insect virus called a baculovirus to bring the spike protein of the coronavirus into moth cells and then produce this protein. It is harvested and mixed with an adjuvant-an immune enhancer based on Quillaja saponins.

Sanofi and GlaxoSmithKline

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

Sinovac and Sinopharm Holdings

The Chinese company Sinovac’s CoronaVac uses an inactivated virus-the oldest method of vaccinating people. The entire batch of coronavirus is grown, “killed”, and then made into a vaccine. Similarly, the vaccine of Sinopharm is inactivated.

Sputnik V

Russia’s Sputnik Type V coronavirus vaccine is an adenovirus vector vaccine. It uses two common cold viruses, called adenovirus 5 and adenovirus 26, to carry the genetic material of the spike protein into the body.