Test subjects a major factor in Sinovac Covid-19 vaccine trial result

A health worker shows a vial of Sinovac's Covid-19 vaccine in the Positivo event center at the Barigui Park in Curitiba, Brazil on Jan 28, 2021. - Reuters

PETALING JAYA: Is the Sinovac Covid-19 vaccine 91.2% effective or 50.3% effective in preventing symptoms of this infectious disease?

Interim results from the Phase Three clinical trial in Turkey show the much higher efficacy, while results from the Phase Three trial in Brazil show the latter.

The main differentiating factor, according to Pharmaniaga R&D head Dr Badarulhisham Abdul Rahman, is the populations the vaccine was tested on.

In Turkey, the Sinovac vaccine was tested mostly on adult volunteers aged 18 to 59 from the general population, with 10% comprising healthcare workers.

In Brazil, the 13,060 trial participants were solely made up of adult and elderly (aged over 60) healthcare workers.

"They were made up of those who were in direct contact with Covid-19 patients, like nurses and doctors, and some in state hospitals who dealt with Covid-19 patients for testing.

"Even though these are professionals who wore protective gear, they were still very much exposed to the virus," said Dr Badarulhisham.

He also said the 50.3% rate reflected the vaccine's ability to protect against very mild symptoms of Covid-19 in this highly-exposed population.

"This is more like the flu – you might get some mild symptoms, but are still very much functional," he said.

"But this is still above the requirement of the World Health Organisation (WHO) for registration and confirmation of vaccine efficacy," he added.

WHO requires that Covid-19 vaccines be at least 50% effective against the disease.

Dr Badarulhisham pointed out that the Sinovac vaccine actually provides protection to over three in four people who receive it (77.9%) against mild symptoms that might need supportive medical treatment, and 100% protection against hospitalisation for moderate or severe disease.

Pharmaniaga is partnering with Chinese pharmaceutical company Sinovac to conduct the fill-and-finish part of its vaccine production here in Malaysia.

The company is expected to produce 14 million vaccines in total, at a rate of two million a month beginning in April.

Twelve million of these doses have been procured by the government for distribution to Malaysians.

The other two million will likely be made available to government-linked companies (GLCs) and the banking industry – or "economic frontliners", as Pharmaniaga group managing director Datuk Zulkarnain Md Eusope terms them – as well as foreigners working in the country.

Zulkarnain told the media via an online press conference that the Sinovac vaccine is expected to receive approval from the National Pharmaceutical Regulatory Agency by the end of this month or early March if all goes well.