How the Sinopharm Covid-19 vaccine works

In early 2020, the Beijing Institute of Biological Products created an inactivated vaccine against coronavirus BBIBP-CorV. It was later put into clinical trials by the state-owned Chinese company Sinopharm. On December 30, Sinopharm announced that the vaccine had an effectiveness of 79.34 percent. The vaccine is now used in Bahrain and the United Arab Emirates. Sinopharm has also applied to the Chinese government for approval.

A vaccine made from coronaviruses

BBIBP-CorV works by teaching the immune system to make antibodies against the SARS-CoV-2 coronavirus. The antibodies attach to viral proteins, such as the so-called vein proteins that study at the surface.

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

Killing the virus

After the researchers produced large stocks of coronaviruses, they used them with a chemical called beta-propiolactone. The compound eliminated the coronaviruses by binding to their genes. The inactivated coronaviruses could not be repeated. But their proteins, including veins, remained intact.

The researchers then extract the inactivated viruses and mix them with a small amount of an aluminum compound called an additive. Aids stimulate the immune system to increase the response to a vaccine.

Activated viruses have been in use for over a century. Jonas Salk used it to create his polio vaccine in the 1950s, and it is the basis for vaccinations against other diseases, including rabies and hepatitis A.

Request an immune response

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

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

Make antibodies

Another type of immune cell, called a B cell, can also encounter the inactivated coronavirus. B cells have surface proteins in a wide variety of forms, and some may have the right form to attach to the coronavirus. If a B cell locks up, it can pull a portion of the virus inside or present coronavirus fragments on the surface.

A helper T cell activated against the coronavirus can attach to the same fragment. If this happens, the B cell is also activated. It multiplies and releases antibodies that have the same shape as their surface proteins.

Stop the virus

Once vaccinated with BBIBP-CorV, the immune system can respond to a live coronavirus infection. B cells produce antibodies that attach to the invaders. Antibodies that target the peak protein can prevent the virus from entering cells. Other types of antibodies can block the virus in other ways.

Remember the virus

Sinopharm’s clinical trials have shown that BBIBP-CorV can protect humans against Covid-19. But no one can yet say how long the protection will last. It is possible that the level of antibodies decreases over the course of 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.

Vaccination timeline

January 2020 Sinopharm begins development of an inactivated vaccine against the coronavirus.

June Researchers report that the vaccine has shown promising results in monkeys. A Phase 1/2 study shows that the vaccine has no serious side effects and enables humans to make antibodies against the coronavirus.

July A Phase 3 trial is set to begin in the United Arab Emirates.

August Phase 3 trials begin in Morocco and Peru.

September 14 The UAE grants emergency permission for the vaccination of Sinopharm for health workers. Government officials and others are beginning to receive it.

November The chairman of Sinopharm says nearly a million people in China have received Sinopharm vaccinations.

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

December 9 The UAE gives full approval to BBIBP-CorV and announces that it has an efficiency rate of 86 percent. But the government did not release any details with their announcement, which left it unclear how they came to their conclusions.

December 13 Bahrain also approves the vaccine.

December 30 Sinopharm announces that the vaccine has an efficacy of 79.34 percent. The company has yet to publish the detailed results of their Phase 3 trial.

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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