How the Sinopharm Covid-19 vaccine works

In early 2020, the Beijing Institute of Biological Products created an inactivated coronavirus vaccine called BBIBP-CorV. Subsequently, he underwent clinical tests by Chinese state-owned Sinopharm. On December 30, Sinopharm announced that the vaccine was 79.34% effective. The vaccine is already in use in Bahrain and the United Arab Emirates. Sinopharm also requested approval from the Chinese government.

A vaccine made from coronavirus

BBIBP-CorV works by teaching the immune system to produce antibodies against the SARS-CoV-2 coronavirus. Antibodies bind to viral proteins, such as so-called peak proteins, which are on their surface.

To create BBIBP-CorV, researchers at the Beijing Institute obtained three variants of the coronavirus from patients in Chinese hospitals. They chose one of the variants because it was able to multiply rapidly in monkey kidney cells grown in bioreactor tanks.

Killing the Virus

As soon as the researchers produced large stocks of coronavirus, they immersed them in a chemical called beta-propiolactone. The compound deactivated coronaviruses by binding to its genes. Inactivated coronaviruses could no longer replicate. But its proteins, including the peak, remained intact.

The researchers then removed the inactivated viruses and mixed them with a small amount of an aluminum-based compound called an adjuvant. Adjuvants stimulate the immune system to increase its response to a vaccine.

Inactivated viruses have been used for more than a century. Jonas Salk used them to create his polio vaccine in the 1950s and they are the basis for vaccines against other diseases, including rabies and hepatitis A.

Requesting an immune response

Since the coronaviruses in BBIBP-CorV are dead, they can be injected into the arm without causing Covid-19. Once inside the body, some of the inactivated viruses are swallowed up by a type of immune cell called an antigen-presenting cell.

The antigen-presenting cell separates the coronavirus and displays some of its fragments on its surface. A so-called auxiliary T cell can detect the fragment. If the fragment fits into one of its surface proteins, the T cell becomes activated and can help recruit other immune cells to respond to the vaccine.

Making Antibodies

Another type of immune cell, called a B cell, can also find the inactivated coronavirus. B cells have surface proteins in a wide variety of forms, and some may have the right shape to attach to the coronavirus. When a B cell is fixed, it can pull part or all of the virus inward and have fragments of coronavirus on its surface.

An auxiliary T cell activated against the coronavirus can attach to the same fragment. When this happens, cell B is also activated. It proliferates and releases antibodies that have the same shape as its surface proteins.

Stopping the virus

Once vaccinated with BBIBP-CorV, the immune system can respond to infection with live coronaviruses. B cells produce antibodies that attach to invaders. Antibodies that target the spike protein can prevent the virus from entering cells. Other types of antibodies can block the virus by other means.

Remembering the virus

Sinopharm’s clinical trials have shown that BBIBP-CorV can protect people against Covid-19. But nobody can say how long this protection lasts. It is possible that the level of antibodies will decrease over the months. But the immune system also contains special cells called memory B cells, which can retain information about the coronavirus for years or even decades.

Vaccines Timeline

January 2020 Sinopharm begins to develop an inactivated vaccine against the coronavirus.

June The researchers report that the vaccine produces promising results in monkeys. A phase 1/2 study shows that the vaccine does not cause serious side effects and allows people to produce antibodies to the coronavirus.

July A Phase 3 test begins in the United Arab Emirates.

August Phase 3 testing begins in Morocco and Peru.

September 14 The UAE gives emergency approval for the Sinopharm vaccine for use by healthcare professionals. Government officials and others begin to welcome you.

November Sinopharm’s president said that nearly a million people in China received vaccines against Sinopharm.

November 3 The Dubai ruler, Sheikh Mohammed bin Rashid al-Maktoum, announce he received the vaccine.

December 9th The United Arab Emirates give full approval to BBIBP-CorV, announcing that it has an efficiency rate of 86%. But the government did not release any details with the announcement, making it unclear how they reached their conclusions.

December 13 Bahrain also approves the vaccine.

December 30 Sinopharm announces that the vaccine is 79.34 percent effective. The company has not yet published the detailed results of its Phase 3 test.

Sources: National Center for Biotechnology Information; Science; The Lancet; Lynda Coughlan, University of Maryland School of Medicine; Jenna Guthmiller, University of Chicago.

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