The coronavirus pandemic is still rapidly spreading worldwide, infecting more than 14.44 million people. With more than 188 countries and territories affected, scientists are competing to develop a vaccine against coronavirus 2 for severe acute respiratory syndrome (SARS-CoV-2), the virus that causes coronavirus disease (COVID-19).
One of the forerunners in this vaccine race is a vector adenovirus vaccine from the University of Oxford, in association with AstraZeneca, which began its human trials in May.
In June, the research team reported the results of the trial that revealed a single dose of ChAdOx1 nCoV-19 (AZD1222) induced by antigen-specific antibodies and T-cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) in animal models.
The vaccine
The Oxford – AstraZeneca vaccine, ChAdOx1 nCov-19, is made from a virus called ChAdOx1, a weakened version of a common cold virus or adenovirus that causes infections in chimpanzees.
The vaccine, now called AZD1222 COVID-19, is being developed at the Jenner Institute at Oxford University and has been licensed by AstraZeneca.
The virus has been genetically modified so that it cannot replicate in humans.
It was developed by adding genetic material, known as a spike glycoprotein, that is expressed on the surface of the coronavirus to the ChAdOx1 virus. Scientists say the vaccine works by making the body recognize and develop an immune response to the spike glycoprotein, preventing the virus from entering human cells.
In June, the team began testing the candidate vaccine in South Africa and Brazil, with 4,000 and 5,000 participants, respectively.
Foster early results
The results of the first human clinical trial of the candidate vaccine will be published later today, July 20, by the journal. The lancet.
“We hope that this document, which is in the process of being edited and finally prepared, will be published on Monday July 20 for immediate publication,” a magazine spokesperson said in a statement.
The researchers revealed that the experimental vaccine provides double protection against SARS-CoV-2 after early-stage human trials. The volunteers’ blood samples showed that the vaccine had caused the body to produce antibodies and killer T cells to fight the infection.
.jpg "SARS-CoV-2 viruses that bind to ACE-2 receptors in a human cell. Image Credit: Kateryna Kon / Shutterstock")
SARS-CoV-2 viruses that bind to ACE-2 receptors in a human cell. Image Credit: Kateryna Kon / Shutterstock
Antibodies are proteins that can effectively kill the antigen, in this case, the new coronavirus. Meanwhile, T cells can kill a virus and the cells it has infected, providing a vital part of the body’s response to viral infections. The results are promising since scientists say that although the antibodies may disappear in a few months, the T cells can remain in the blood longer.
The phase 1 trial involving approximately 1,000 British volunteers has been completed, and the results will be published in the journal on July 20. The lancet. The team is now preparing for the Phase 3 trial, which will recruit tens of thousands of people in the UK, Brazil, the United States, and South Africa. Along with phase 3 testing, the team plans a challenge test.
Challenge test
Now, the Oxford vaccine team plans to begin testing on volunteers who will be intentionally exposed to the virus in a “challenge trial,” which has been deemed controversial since there is no approved drug yet to fight the infection.
In challenge trials, recruited volunteers are healthy and without any underlying health conditions. These volunteers are intentionally exposed to the pathogen in a controlled laboratory environment, which means it can be completed in weeks and requires fewer people than other types of tests.
“We hope to carry out challenge tests by the end of the year. This could be in parallel or it could be after phase three of testing is complete. They are not competing for options, they are complementary, ”said Professor Adrian Hill, director of the Jenner Institute at the University of Oxford. He added that the team is now preparing the laboratory on the technical side of the test. In a couple of months, the team hopes to recruit willing volunteers.
The coronavirus continues to spread throughout the world. With many countries beginning to reopen their economies and ease blockade measures, the number of cases is expected to skyrocket in the coming months. The situation highlights the dire need for an effective vaccine to contain the spread of the virus and protect people from infection.
The United States continues to be the nation with the highest number of infections, reaching 3.76 million with a death toll of more than 140,000. Brazil and India continue with a staggering 2.01 million and 1 million confirmed cases, respectively.
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