The world's first phase I clinical trial of a vaccine against severe acute respiratory syndrome (SARS) has started in China. The inactivated-virus vaccine was developed by the company Sinovac and researchers from the Chinese Academy of Medical Sciences, both in Beijing. On May 22, four volunteers were injected with vaccine or placebo at the China-Japan Friendship Hospital, Beijing. A second shot will be given 28 days after the first and all volunteers will be followed-up for 210 days. Altogether 32 volunteers from Beijing provinces will participate in the trial
As TLID went to press no adverse reaction had been registered. “The fact that the Chinese are moving forward with trials…is unprecedented in terms of the speed with which we've gone from identifying a new infectious agent to a prototype vaccine”, comments Gary Nabel (Vaccine Research Centre, NIH, Bethesda, MD, USA), whose team hopes to start their own phase I trials on a DNA vaccine later this year.
“The reason to enter a clinical trial is because we have done a lot of tests on different animals, such as mice, guineapigs, rats, rabbits, and Rhesus monkeys which have shown positive results with no immune enhancement occurring”, says Helen Yang, Sinovac spokesperson. Nabel cautions that should SARS be contained as successfully as last year, it may not be possible to do a human vaccine study capable of showing efficacy. “If that's the case, then before moving to much larger numbers of people, we definitely need better animal models. I don't think that any of the models that have been tested to date really give a very faithful model of the human disease.”
The Chinese State Food and Drug Administration is fast-tracking the drug approval process for the Sinovac vaccine. “Based on the regular drug approval process in China, it would take between 3 and 5 years for a SARS vaccine to receive final commercial approval. With fast-tracking, it could take as little as 1 to 2 years”. Whether or not such a compressed timetable proves feasible, phase I trials will yield an initial assessment of immunogenicity and safety in human beings. “While these new vaccines are being generated, they do provide some tools to work with if there should be an outbreak”, Nabel concludes.