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Brazilian researchers report disappointing 50.4% efficacy of Chinese CoronaVac vaccine – Times of India

RIO DE JANEIRO: A vaccine against the coronavirus developed by Chinese Sinovac showed “general efficacy” of 50.4% in an advanced stage trial in Brazilbarely enough for regulatory approval and far from previous guidance, the researchers said on Tuesday.
The latest results are a big disappointment for Brazil, as the Chinese vaccine is one of two vaccines that the federal government has lined up to begin vaccination during the second wave of the world’s deadliest Covid-19 epidemic .
The disappointment after a more promising partial data release last week may also contribute to criticism that vaccines developed by Chinese manufacturers are not subject to the same public scrutiny as US and European alternatives.
Brazilian researchers last week celebrated results showing 78% effectiveness against Covid-19 cases, a rate they have since described as “clinical effectiveness.”
Ricardo Palacios, medical director of clinical research at the Butantan biomedical center in Sao Paulo, said the new figure included infections classified as “very mild” because they did not require clinical assistance.
Butantan researchers have delayed announcing their results three times, accusing a confidentiality clause in a contract with Sinovac.
In the meantime, researchers in Turkey said last month that CoronaVac was 91.25% effective based on an interim analysis. Indonesia on Monday gave approval for emergency use of the vaccine based on provisional data showing it is 65% effective.
Butantan officials said the design of the Brazilian study, which focused on frontline health workers during a severe epidemic in Brazil and included elderly volunteers, made it impossible to directly compare the results with other trials. or vaccines.
Yet the Covid-19 vaccines used by Pfizer Inc with its partner BioNTech SE and Moderna Inc have been shown to be around 95% effective in preventing the disease in their pivotal late stage trials.
Disappointing data from CoronaVac is the latest setback for vaccination efforts in Brazil, where more than 200,000 people have died since the start of the epidemic – the worst toll outside of the United States.
Brazil’s national immunization program currently relies on CoronaVac and the vaccine developed by the University of Oxford and AstraZeneca Plc – none of which has received regulatory approval in Brazil.
Brazilian health regulator Anvisa, which has stipulated an efficacy rate of at least 50% for vaccines in the pandemic, has already pressed Butantan for more details on his study, after filing for an authorization for use on Friday. emergency.
AstraZeneca failed to deliver active ingredients to Brazil over the weekend, leaving t

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