Editor’s note: While the world’s attention is on COVID-19 vaccine development, scientists around world are also racing against time for HIV vaccines. How close is China to developing an HIV vaccine? Shao Yiming, chief expert on AIDS at the Chinese Center for Disease Control and Prevention, shared his views.
CGTN: Can you brief us about the progress of China’s HIV vaccine？
Shao Yiming: We made our design different from other groups in the world. We do not use natural immunogen. We redesigned the HIV immunogen based on the first lentiviral vaccine. The first lentiviral vaccine is for a horse virus that has been invented by Chinese scientists in the 70s. We worked with Professor Shen, who invented the first lentiviral vaccine, and studied his mechanism, and we found a structure change on the envelope of this protein between the vaccine’s strain and wild type strain. Based on that, we redesigned the envelope of the HIV vaccine. This is one innovation.
Second innovation: We thought maybe not only the antibody, we still need the T cell immune response. We designed what we called heterologous prime-boost approach by priming the human or animal with DNA vaccine, and boost with another viral vector, which is a poxvirus. Again, different from many other groups that use non-replicating dead vector, we are using replication-competent live vector. So what we chose is the Chinese smallpox vaccine which has been used in the last century to eradicate smallpox in China. We use this vector by traditional skin scarification. In this combination, we can stimulate good antibody response and T cell response.
We have concluded three Phase-1 trials. We concluded the first Phase-2 trial of this type of replicating competent viral vector HIV vaccine. We are currently doing a second Phase-2 trial with additional vector boost. We are moving this vaccine project next year into Phase-3 trial — the last one to test if this vaccine works or not.
I should say, HIV vaccine is one of the most difficult scientific projects facing mankind. So, we don’t wish our design to be done by ourselves alone. We want to do it with international collaboration.
CGTN: When do you expect the first Chinese HIV vaccine to be ready?
Shao: We will initiate a Phase-3 trial next year. The trial takes about two and half years, I think in about three years and a half, we will get the results. Even though we have hope, scientific research is not the same as going to a fortune teller. We cannot tell the result beforehand. So we do our best, but we are prepared for either positive or negative results.
CGTN: What’s your take on relying on vaccine to prevent HIV infections?
Shao: What we have learned in the last 40 years, for a virus like AIDS which transmits closely linked with human behavior, there’s no silver bullet. We cannot imagine with one tool to end the epidemic. We have to always use a combined approach, a comprehensive approach, both social behavioral intervention through education, and also by medical intervention through drugs and vaccines. Success can only be reached by using all the tools and a vaccine is just one of the tools in the box.
(If you want to contribute and have specific expertise, please contact us at email@example.com.)