Photographer: Lintao Zhang / Getty Images
Photographer: Lintao Zhang / Getty Images
Days before a global launch begins with the reception of the President of Indonesia Vaccination against Sinovac Biotech Ltd. on live television, uncertainty is swirling about the effectiveness of the leading Chinese shot, for which four different protection figures have been released in recent weeks.
Indonesia, which is moving the fastest to distribute the Sinovac shot to its population, said a local trial has a 65% effectiveness compared to Covid-19. But only 1,620 people in Indonesia took part in the trial – too small for meaningful data.
Turkey said last month that the same vaccine shows an efficiency of 91.25% in its local experiment, which was also too small to draw a sufficient conclusion.
In Brazil, where the largest trial of Sinovac is being conducted among more than 13,000 people, twin efficiency rates have been announced. The company’s local trial partner, Butantan 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.
Still a local news site reported this week that the “true” efficiency rate was between 50% -60%, citing unnamed sources. According to the Butantan Institute, it is ‘speculative’ and that it will release additional data on Tuesday.
Overlapping efficacy data are not unprecedented in the Covid-19 vaccine breed – AstraZeneca Plc last month released two separate protection figures based on different dosing systems – and all the findings are above the 50% efficacy threshold required by regulators for approval.
China struggles to enable world to trust its vaccines
The confusion, which comes as several governments commit themselves to vaccinating their citizens with Sinovac’s lap, fuels skepticism about Chinese vaccines, which revealed less safety and test information than Western forerunners. The data kerfuffle could undermine the confidence in shots that President Xi Jinping has promised to share with the rest of the world as a global public benefit.
“There is enormous financial and significant pressure for these trials to overestimate their results,” said Nikolai Petrovsky, a professor at the College of Medicine and Public Health at Flinders University.
“In many cases, such retellings have also been politically motivated, as countries that did not properly control the pandemic now want to exaggerate the benefits of the vaccines to win votes and appease local unrest.”
A Sinovac spokesman declined to comment on the numbers of his trials in Brazil, Turkey and Indonesia and said more information would be released this week by his Brazilian partner.
It seems that the data issue in some places already holds the regulatory approval of Sinovac’s vaccine.
‘Initially, Sinovac would send the vaccine supply to Hong Kong in January. But they have delayed the release of the Phase III clinical trials three times, ‘said David Hui, a professor of respiratory medicine at the Chinese University of Hong Kong, who is on the Asian Financial Center’s Covid-19 advisory panel. . “This will delay the evaluation of their application.”
Calculation Confusion
The massive trial in Brazil, which according to Sinovac will be where he gets the definitive effectiveness data, has been intensively investigated.
Observers were outraged at the first 78% efficiency rate announced by Butantan Institute. According to the information revealed, about 220 participants in the trial were infected: 160 in the placebo group and almost 60 in the vaccinated group.
If trial participants are evenly divided between the vaccine and placebo groups, the efficacy rate should be 62.5%, Petrovsky said. He is also research director of Vaxine Pty Ltd., a company developing a Covid-19 vaccine.
External calculations remain speculative unless more data, such as the total number of people in the placebo group and vaccinated group, are published in peer-reviewed scientific journals, said Raina MacIntyre, head of the Biosecurity program at the Kirby Institute at the University of New York. South, said. Wallis.
It remains unclear whether Sinovac’s trial in Brazil deviates from the protocol to some extent. This was the case with the survey developed by AstraZeneca and Oxford University: a 90% protection rate was found when the first dose was first delivered, followed by a full dose, which was done accidentally. Two full doses, as designed by researchers, show an efficiency of only 62%.
Brazilian drug regulator Anvisa is requesting additional information from the Butantan Institute on the Sinovac shot test, including whether dose deviation has occurred and its impact, before deciding whether to approve the vaccine for use.