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What we should know about China’s CoronaVac

Sinovac Biotech is a Chinese biopharmaceutical company that focuses on the research, development, manufacture and commercialization of vaccines that protect people against infectious diseases.

MJ Blancaflor

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The government announced on Thursday that the Philippines’ first coronavirus vaccine will arrive over the weekend.

Officials have said that 600,000 vaccine doses — donated by Beijing and developed by China-based drugmaker Sinovac Biotech — will be shipped to the Philippines via a military aircraft on Sunday, with the arrival ceremony to be held at Villamor Airbase in Pasay City.

What do we know about the vaccine and how does it compare to those being developed elsewhere?

Sinovac Biotech is a Chinese biopharmaceutical company that focuses on the research, development, manufacture and commercialization of vaccines that protect people against infectious diseases.

Its commercialized vaccines include Healive (hepatitis A), Bilive (combined hepatitis A and B), Anflu (influenza), Panflu (H5N1) and PANFLU.1 (H1N1).

The firm is developing vaccines for enterovirus 71 and human rabies.

But more importantly, it has developed CoronaVac, an inactivated virus Covid-19 vaccine.

The vaccine works by using “killed” viral particles or traditional technology to expose the body’s immune system to the virus and help it produce antibodies to fight off Sars-Cov-2, the virus which causes Covid-19, without risking a serious disease response.

To develop the vaccine, Sinovac researchers obtained coronavirus samples from patients in China, Britain, Italy, Spain, and Switzerland, then grew large stocks of it in monkeys’ kidney cells.

They doused the viruses with a chemical called beta-propiolactone to make it “inactivated.”

CoronaVac could be distributed to far-flung areas since it only requires 2 degrees Celsius (36 Fahrenheit), a temperature within the existing cold chain system in the country in which flu vaccines are kept.

Its storage requirement is comparable to Oxford-AstraZeneca’s coronavirus vaccine, which is made from a genetically engineered virus.

Efficacy rates

CoronaVac has been in Phase III clinical trials in Brazil, Chile, Indonesia, and Turkey, and its different efficacy rates have gotten attention in the country as early as of November last year.

Philippine lawmakers in the Senate have scrutinized the Duterte administration’s seeming preference for the Chinese vaccine despite its reported higher prices and its supposed confusing efficacy findings than other vaccine brands.

Researchers in Brazil initially said that CoronaVac was 78 percent effective in their clinical trials, which had recruited 12,396 medical workers older than 18 — a rate lower than that of Pfizer and Moderna.

In January, the researchers included more data in their calculations and revised the figure to 50.4 percent — barely passing the threshold set by the World Health Organization.

Sinovac’s executives defended the vaccine’s low efficacy rate in Brazil, arguing that their participants are medical workers who are likely to contract Covid-19.

On the other hand, interim data from the vaccine’s late-stage trials in Turkey and Indonesia showed that the jab was 91.25 percent and 65.3 percent effective, respectively.

The trial participants were not health care workers and came from other segments of the population.

CoronaVac is the sole vaccine brand which was known to be tested among medical workers.

The firm also said the effectiveness of its coronavirus jab increased by 20 percentage points in a small sub-group of patients who received their two doses three weeks apart.

Earlier in November, Sinovac’s trials were briefly halted after the reported death of a volunteer, but resumed after it was found to have no links to the vaccine.

The vaccine has been approved for emergency use in high-risk groups in China since July.

Side effects

There were no severe side effects reported with the vaccine.

Helen Yang, general manager of Sinovac’s Hong Kong office, said muscle pain is the only common side effect of the jab “due to the aluminum hydroxide which is adjuvant in the vaccine.”

“So, people just feel muscle pain after getting vaccination but it can go over after a day,” she said in a televised Palace briefing on Wednesday (Philippine time).

“There hasn’t been any fatal impact of relating to the use of the vaccine,” she added.

Which countries are signing up?

At least 12 countries have been using CoronaVac, according to Yang, which include Singapore, Indonesia, Malaysia, Thailand, and Hong Kong.

Turkey has also approved the Sinovac vaccine for emergency use and the company has also secured other deals with Brazil, Chile, Colombia, Mexico, and other Latin American countries.

“This number will go up to 15 by the end of this week,” Yang said in the news conference.

Price

Lawmakers have previously questioned its supposed higher price after it was reportedly sold at P1,814.75 per dose in the country.

After criticisms, Malacañang has said the government will purchase it for about P650 per dose only, which Palace spokesman Harry Roque called “presyong BFF (best friend forever/ at a friendly price)”.

Vaccine czar Secretary Carlito Galvez Jr. has explained the national government cannot disclose yet the actual negotiated prices of vaccines with manufacturers so as not to hamper the ongoing talks.

He has vowed to disclose all vaccine prices to the public in due time.

FDA approval

The Philippines’ Food and Drug Administration (FDA) has approved Sinovac’s coronavirus shots for emergency use, but the regulatory board did not recommend its use for health workers frequently exposed to the virus due to its 50.4 percent efficacy rate in the Brazil trial.

The vaccine was also not recommended for the elderly and individuals with underlying medical conditions, since its trials only included healthy people aged 18 to 59.

CoronaVac cannot be administered yet to recipients pending an official recommendation on its use, according to the health department.

Health care workers, the elderly, and people with comorbidities are supposed to receive the first Covid-19 vaccines in the country based on the priority list prepared by the government.

Officials have yet to announce whether the list needs to be shaken up in line with the FDA’s advice.

Specific details as to the allocation and subsequent rollout of the doses are still being evaluated by the National Immunization Technical Advisory Group, which is composed of experts on immunology, infectious diseases, among others.

The decision has to be approved by the pandemic task force.

The Philippines is expecting a total of 25 million vaccine doses from the Chinese firm this year.

Details of CoronaVac’s planned arrival ceremony are “still being finalized in close coordination” with the Embassy of the People’s Republic of China, the health department said.

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