Researchers in South Africa and Brazil have initiated clinical trials to assess a Covid-19 vaccine candidate, ChAdOx1 nCoV-19 (AZD1222), developed by the University of Oxford and licensed to AstraZeneca.

Sponsored by Lemann Foundation, the trial in Brazil will assess the vaccine candidate in 2,000 health workers in Sao Paulo and 1,000 people in Rio de Janeiro.

Brazil’s health regulator Anvisa approved trials of the vaccine earlier this month. Researchers expect to launch the Covid-19 vaccine by the end of this year.

Meanwhile, the University of Witwatersrand in South Africa is working with the University of Oxford and the Oxford Vaccine Group to evaluate the vaccine candidate. This marks South Africa’s first trial of a vaccine against Covid-19.

Named Ox1Cov-19 Vaccine VIDA-Trial, the South African study will be led by Witwatersrand University vaccinology professor Shabir Madhi. The trial will be performed at several sites across South Africa.

The South African Health Products Regulatory Authority (SAHPRA) and the University of the Witwatersrand’s Human Research Ethics Committee approved the study.

Madhi noted: “This is a landmark moment for South Africa and Africa at this stage of the Covid-19 pandemic. As we enter winter in South Africa and pressure increases on public hospitals, now more than ever we need a vaccine to prevent infection by Covid-19.”

Screening of participants for the South African Oxford Covid-19 vaccine study commenced last week and the first participants are set to be vaccinated this week.

The vaccine candidate is made from ChAdOx1 virus, which is a weakened and non-replicating version of a common cold virus called adenovirus. Created at the Oxford University’s Oxford Jenner Institute, the vaccine has been engineered to express the SARS-CoV-2 spike protein.

Following vaccination, the human body is expected to identify and develop an immune response to the spike glycoprotein, in turn blocking the entry of SARS-CoV-2 virus into human cells.

In the UK, the vaccine’s trial has already enrolled more than 4,000 participants, with plans to enrol an additional 10,000 volunteers.