There have been over 15 million confirmed cases of the new coronavirus, SARS-CoV-2, and more than 624,000 COVID-19 deaths globally. Thus, scientists around the world have been competing against time to speed up the development of new treatments to combat the disease.
Around the world, scientists have been developing about 250 candidate vaccines against SARS-CoV-2 infection. Out of the 250, about, at least 17 were under evaluation in clinical trials.The scientists of the recent study have aimed to evaluate the safety and efficacy of a vaccine candidate called adenovirus type-5-vectored COVID-19 vaccine (Ad5-vectored COVID-19 vaccine).
They have also wanted to determine the most appropriate dose for a phase III trial in the coming months. They published their results in The Lancet.
The Beijing Institute of Biotechnology in Beijing, China, and CanSino Biologics developed the Ad5-vectored COVID-19 vaccine. This vaccine uses a weakened human common cold virus (adenovirus) that produces an immune system response, including antibodies, to fight off the coronavirus.
Danny Altmann, Professor of Immunology at Imperial College London in the United Kingdom, who was not involved in the study, told the Science Media Centre in London:
“The Beijing approach is based on the backbone of a conventional human, common cold virus to which some people have preexisting antibodies, and they, therefore, make a lower response in some people to the vaccine because people have preexisting antibodies to their vector, so may clear it before it has a chance to work properly.” (Source: Medical News Today)