China approves its first human H5N1 vaccine
[BEIJING] China's State Food and Drug Administration approved production of the country's first human vaccine for the H5N1 virus last week (2 April).
Developed by Beijing Sinovac and the Chinese Center for Disease Control and Prevention (China CDC), the vaccine is based on whole, inactivated virus particles of a H5N1 strain identified by the WHO in Vietnam.
Similar vaccines made by French pharmaceutical companies Aventis Sinofi, UK-based GlaxoSmithKline and the Swiss firm Norvatis received their production licences between March 2007 and February 2008, but have so far not been approved in China.
Like its Western counterparts, the Sinovac vaccine was approved after two phases of clinical trials — enrolling a total of 402 participants — showed its safety and ability to induce an immune response.
The third phase, to test whether the vaccine prevents real infection, has not yet been carried out, as there has been no massive spread of H5N1 influenza in people.
Without the phase III clinical trial, approvals for the Sinovac vaccine and other H5N1 vaccines are currently for production only, rather than direct vaccination.
There is widespread concern that the viral strain that could eventually cause a pandemic will be a mutated form, invalidating the stockpiles based on the current epidemic strain.
Dong Xiaoping, a researcher at China CDC and chief scientist of the Sinovac vaccine, told SciDev.Net that if pandemic flu were caused by a new strain, the vaccine would be immediately updated with the new strain, without the need to redesign and renovate production facilities.
The SFDA license would allow such a vaccine to be put into use without extra clinical trials.
"Before the new strain identification, the stockpiled vaccine will offer protection as much as possible amidst possible pandemic flu," Dong told SciDev.Net.
He added that monitoring of the development of H5N1 has shown that mutation of the virus has not so far been as extensive as predicted.