What do we know about the Chinese coronavirus vaccine?


Various medical syringes with the Sinovac Biotech logo in the background.

Sinovac is a Beijing-based pharmaceutical company

Chinese vaccine producers Sinovac and Sinopharm have signed a global vaccine sharing scheme, Covax, aimed at distributing vaccines to poorer countries.

The Global Alliance for Vaccines and Immunization (Gavi) said it plans to make 110 million doses of vaccine available as part of the scheme.

Covax It has contracts with 11 vaccine manufacturers and plans to provide 2 billion doses worldwide by early 2022.

Approved for emergency use by the World Health Organization (WHO), Sinopharm and Sinovac are already in use in China and dozens of countries around the world.

But what do we know about Chinese vaccines, and how are they compared to those being developed elsewhere?

How does the Sinovac vaccine work?

Beijing-based biopharmacy company Sinovac is behind the inactivated vaccine CoronaVac.

It works by using killed viral particles to expose the body’s immune system to the virus without risking the reaction of a serious illness.

By comparison, the Moderna and Pfizer vaccines are mRNA vaccines. This means that part of the coronavirus’s genetic code is injected into the body and the body begins to produce viral proteins, but enough to train the body to attack the immune system, not the entire virus. is.

“CoronaVac is a more traditional method [of vaccine] It has been successfully used in many well-known vaccines such as rabies, “Associate Professor Luo Hai of Nanyang Technological University told the BBC.

On paper, one of the main benefits of Sinovac is that it can be stored in a standard refrigerator at 2-8 degrees Celsius, like the Oxford vaccine made from a genetically engineered virus that causes the chimpanzee’s cold.

In contrast, Moderna vaccines should be stored at -20 ° C and Pfizer vaccines should be stored at -70 ° C.

This means that both the Sinovac and Oxford-AstraZeneca vaccines are far more useful in developing countries, which may not have facilities to store large amounts of vaccine at such low temperatures.

Graph showing the most used vaccines: Oxford-AstraZeneca Top, Pfizer-BioNTech

Graph showing the most used vaccines: Oxford-AstraZeneca Top, Pfizer-BioNTech

How effective is it?

When the WHO approved the jab in June, the Sinovac vaccine “prevented symptomatological illness in 51% of vaccinated individuals and resulted in 100 severe Covid-19 and hospitalizations” for adults over the age of 18. Prevented by%, “said WHO.

He added that it was not possible to estimate the efficacy of that age group because only a few adults over the age of 60 were enrolled in clinical trials.

According to a study published in the New England Journal of Medicine In Chile, Sinovac is 65.9% effective against Covid-19, 87.5% effective in preventing hospitalization and 86.3% effective in preventing death.

However, there is little data on its effectiveness against delta variants.

How about the Shinofarm vaccine?

WHO has approved the Sinopharm vaccine manufactured by a Chinese state-owned enterprise.

Like Sinovac, it is an inactivated vaccine that causes the production of antibodies that fight the coronavirus.

The virus cannot infect Covid-19 because it is killed before it is injected into the human body.

At that time, WHO said: “Vaccine efficacy against symptomatological and inpatient disorders was estimated to be 79% for all age groups combined.”

However, he added again that there were not enough enrolled clinical trials in his 60s or older to estimate the effectiveness of the age group. Still, we recommend vaccines for the elderly.

Women are vaccinated with a Chinese COVID-19 vaccine syringe developed by the pharmaceutical company Sinopharm

Both United Arab Emirates and Bahrain use Chinese vaccines

According to the National Health Commission of China, China has given its inhabitants more than a billion doses of vaccine.

The epidemic of the coronavirus in China is largely contained and the country is widely open.

Which country is receiving the Chinese vaccine?

More than 80 countries, including many in Asia, including Indonesia, Thailand, Malaysia, Vietnam and the Philippines, use China’s Covid vaccine.

However, some countries that have opted for jabs in China have high immunization rates and are still experiencing a surge in infections.

For example, Chile has re-imposed a curfew and reinstated travel restrictions in response to the more contagious Delta subspecies than its predecessors.

Over 70% of Chileans are fully vaccinated, most of whom are vaccinated with the Sinovac vaccine.

Seychelles and Mongolia, on the other hand, have recently recorded the highest per capita cases despite their small population.

Both are heavily dependent on Sinopharm and the vaccination program is in progress. 68% of adults are fully vaccinated in Seychelles and 55% in Mongolia.

Thailand changes its vaccination policy to mix China’s Sinovac and AstraZeneca vaccines to enhance protection after catching Covid, despite hundreds of healthcare workers being fully vaccinated with Sinovac Did.

Meanwhile, in Indonesia, a major association of doctors and nurses said at least 30 healthcare workers died despite two doses of the Sinovac vaccine.

The country is currently planning to switch to another Covid-19 vaccine or administer a booster shot for a second dose to increase efficacy.

So is the vaccine failing?

Vaccines are not the only factor that explains what is happening in these countries.

One of the reasons may be that the vaccine may be less effective or less effective against new variants.

Pfizer recently said it would seek approval for booster shots in the United States to boost immunity.

Indonesian man gets Sinovac jab

Indonesia has a very low vaccination rate despite the availability of Chinese vaccines.

However, there are other factors to consider.

In Indonesia, the Association of Physicians said comorbidities may have played a role in the death of health care workers.

Vaccination rates in this country are also very low, with over 5% of the population receiving both vaccinations.

In Chile, some experts have blamed the surge in cases of mixed people shortly after the first dose of the vaccine.

Professor Ben Cowling, Head of Epidemiology and Biostatistics at the University of Hong Kong, Said despite having “moderate efficacy” For symptomatic Covid, both Sinovac and Sinopharm offer a “very high level of protection” against severe illness.

“That is, these inactivated vaccines would have already saved many lives,” he told the BBC.

How do mutants affect vaccines?

However, a study by Sinovac and Sinopharm tested the effectiveness of the vaccine against the first virus found in Wuhan, China. No new data has been published on how they deal with variants.

Based on a study attempting to model immune defenses from the virus, Professor Cowling said that the protection provided by inactivated viral vaccines against delta mutants could be up to 20% lower than in the original strain. I presume that there is.

His calculations suggest an even greater reduction against the first beta variant found in South Africa. This is the most different from the original virus.

Professor Jin Dong-yang, also a virologist at the University of Hong Kong, told the BBC that the effectiveness of Chinese vaccines is “expected” to be reduced against mutants containing delta.

But he states that “Sinovac and Sinopharm are excellent vaccines,” and even those who do not have access to more effective vaccines need to be injected.

However, he said they should continue to follow social distance rules and other means to control infection.

Report by Pablo Uchoa and Yvette Tan

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