Volunteers receive first doses of experimental vaccine

Covid-19 vaccine may not work for at-risk older people, say scientists

From The Guardian:

Volunteers in Brazil have begun to receive injections of an experimental coronavirus vaccine developed by researchers at Oxford University, AFP reports.

The vaccine, developed together with pharmaceuticals group AstraZeneca, is one of dozens that researchers worldwide are racing to test and bring to market.

Known as ChAdOx1 nCoV-19, it is already being tested in volunteers in Britain, and was due to start being administered this week in South Africa as well.

The Federal University of Sao Paulo (UNIFESP), which is coordinating the study in Brazil, said in a statement its researchers had begun issuing the first doses on Tuesday to health workers, including doctors, nurses and ambulance drivers, who were deemed to be likely to come into contact with the Sars-CoV-2 virus.

Researchers “began triaging volunteers [on] Saturday ... following the protocols established for the study. Participants must test negative for Sars-CoV-2, the virus that causes Covid-19,” the university said in a statement.

“Starting Tuesday, volunteers with a negative blood test were administered the vaccine.”

Volunteers must be between 18 and 55 years old and work “on the frontline” of the pandemic at the Sao Paulo-UNIFESP hospital, it said.

The vaccine will be administered to 2,000 volunteers in Brazil, while more than 4,000 participants are enrolled in the clinical trial in Britain, with another 10,000 due to be recruited, according to Oxford.

Brazil was selected because it is one of the countries where the virus is spreading fastest. It has the second-highest caseload and death toll worldwide after the United States, with more than 1.1 million people infected and 52,000 killed so far.

Brazil’s acting health minister, Eduardo Pazuello, said on Tuesday the country was close to signing a contract to produce the vaccine domestically.