Covid-19 vaccine: Oxford to take volunteers from Brazil for clinical trials

Brasilia, June 05: Brazil reported record daily 1,473 more COVID-19 deaths, the biggest 24-hour increase in the country's death toll since the outbreak began. That's equal to more than one death per minute, and means the country now has the world's third-highest death toll.

Mexico on Wednesday announced more than 1,000 deaths in a day for the first time, while Brazil reported a record 1,349 daily deaths.

Meanwhile, the clinical trial for a vaccine conducted by experts at the University of Oxford will soon recruit 2,000 volunteers in Brazil.

The University of Oxford said that the Brazilian Health Regulatory Agency approved the inclusion of Brazil in the clinical trials.

Scientists are resuming Covid-19 trials of the now world-famous drug hydroxychloroquine, as confusion continues to reign about the anti-malarial hailed by US President Donald Trump as a potential "game-changer" in fighting the pandemic. It follows widespread criticism of the quality of data in a study in The Lancet which found high risks associated with the treatment.

The University and AstraZeneca have embraced a recombinant vaccine called AZD1222 to achieve a similar effect, engineering a chimpanzee adenovirus to carry DNA for the spike antigen. Because adenoviruses are themselves immunogenic, such types of approach could generate robust memory B cell and T cell responses that might result in better prophylaxis with fewer doses.

It should be noted that vaccine development is typically a long game. The US Food and Drug Administration only approved a first vaccine against Ebola virus last year, 43 years after the deadly virus was discovered.

In total, WHO lists more than 100 candidates in preclinical development. Many of the preclinical programmes exist on paper rather than in reality, cautions Wayne Koff, CEO of the Human Vaccines Project.