Science

The Chinese COVID-19 injection has four completely different efficacy rates

Days before the start of the global campaign, with the President of Indonesia receiving the Sinovac Biotech Ltd. On live TV, there is uncertainty about the effectiveness of the flagship Chinese footage, for which four different protection rate numbers have been released in recent weeks.

Indonesia, which is moving the fastest to distribute a Sinovac dose to its population, said a local trial had shown 65% effectiveness against COVID-19. But only 1,620 people in Indonesia participated in that experiment – and it’s too young to provide useful data.

Turkey said last month that the vaccine itself had shown a 91.25% efficacy in its local trial, which was similarly too small to yield an adequate result.

In Brazil, where the largest trial of Sinovac is taking place with more than 13,000 people, contrasting efficacy rates have been announced. The company’s local trial partner, Botantan Institute, said last week that the vaccine was 78% effective in preventing mild cases of COVID-19 and 100% effective against severe and moderate infections.

However, Butantan said Tuesday that the overall rate, which also includes very mild cases that do not require medical help, is actually 50.38%.

Overlapping efficacy data is not unprecedented in the COVID-19 vaccine race – AstraZeneca PLC released two separate protection ratios based on different dosing regimens last month – and all results are well above the 50% effectiveness threshold required by regulators to obtain approval.

However, the confusion that comes with the commitment of many governments to vaccinate their citizens with the Senovac bullet is fueling Doubts about Chinese vaccines, Which revealed less safety and testing information than the Western contestants. The disagreement over the data risks undermining confidence in the footage that President Xi Jinping promised to share with the rest of the world as a global public good.

“There is tremendous financial pressure and prestige pressure for these experiments to overestimate their results,” said Nikolai Petrovsky, a professor in the School of Medicine and Public Health at Flinders University.

“In many cases, such overestimation is also politically motivated, as countries that failed to properly control the epidemic now want to exaggerate the benefits of vaccines to gain votes and quell domestic unrest.”

A Sinovac spokesperson declined to comment on its experience numbers in Brazil, Turkey and Indonesia, and said that more data would be released by its Brazilian partner this week.

The data problem appears to be actually hindering regulatory approval for the Sinovac vaccine in some places.

Workers unload Sinovac vaccines for COVID-19 from a truck at a warehouse in Banda Aceh, Indonesia, on Tuesday. | Agence France-Presse – Gigi

Initially, Sinovac had intended to ship vaccine supplies to Hong Kong in January. “But they have delayed the release of data for phase III clinical trials three times,” said David Hui, a professor of respiratory medicine at the Chinese University of Hong Kong, who sits on the Asian Financial Center’s COVID-19 advisory committee. This would delay the evaluation of their requests. “

The massive Brazilian trial, which Senovac said will be where it gets its final efficacy data, has been under intense scrutiny.

Observers were stunned by the first efficacy rate of 78% announced by the Butantan Institute. According to the information disclosed, about 220 participants were infected in the trial: 160 in the placebo group and about 60 in the vaccinated group.

If the trial participants were split evenly between the vaccine and the placebo group, the efficacy rate should reach 62.5%, said Petrovsky, who is also the director of research at Vaxine Pty Ltd. , Which is a company developing a COVID-19 vaccine.

Raina MacIntyre, head of the Biosecurity Program at the Kirby Institute at the University of New South, said external calculations remain speculative unless more data, such as the total number of people in the placebo group and the group vaccinated, are released in peer-reviewed scientific journals. Wells.

Officials said Botantan on Tuesday clarified that 78% accounted for mild, moderate and severe cases. When very slight cases among the 13,000 volunteers are included, the figure is 50.4% – 167 volunteers infected in the placebo arm, and 85 in the vaccine arm. The shot is proven to be 100% effective in preventing severe cases.

Brazilian health organization Anvisa requested additional data from the Butantan Institute on the Sinovac trial before deciding whether to approve the use of the vaccine.

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