From SARS to H7N9: will history repeat itself?

China will never forget the epidemic of severe acute respiratory syndrome (SARS), for which it paid such a heavy and painful price a decade ago. According to WHO, from Nov 1, 2002, to July 31, 2003, 648 of the 7082 probable cases of SARS in mainland China and Hong Kong died. Many of the patients were front-line health workers. At that time, in the wake of its initial negative response to SARS, as well as proof of its fragmented and ineffective public health system, the Chinese Government's international reputation and domestic credibility were seriously damaged.

10 years on, the shadow of SARS is again hovering over Chinese hearts with the emergence of the novel influenza A (H7N9) virus. By the time The Lancet went to press, 63 confirmed cases of H7N9 human infection, including 14 deaths, had been reported over a wide area, ranging from eastern China (Shanghai, Jiangsu, Zhejiang, and Anhui provinces), central China (Henan province), to northern China (Beijing). Unavoidably, there are pervasive worries that history might repeat itself.

SARS coronavirus and H7N9 virus share some similarities. Neither virus had been reported in human beings previously. Worldwide, people of all ages have had little protective immunity, and there is a global pandemic threat. Both viruses can lead to severe disease, characterised by high fever, severe respiratory symptoms, and deaths. Additionally, the sources fuelling human infections of both viruses remain to be determined. SARS coronavirus is thought to be an animal virus from an as-yet-uncertain animal reservoir (perhaps bats) that spreads to other animals (civet cats) and then to the first infected human beings in southern China in 2002. As for H7N9 virus, the animal reservoir seems to be poultry. However, some patients had contact with poultry just before falling ill, whereas others had not.

Unlike SARS coronavirus transmission, sustained transmission of H7N9 virus between human beings has not yet been found. Worryingly, genetic changes among H7N9 virus suggests adaptation to mammals, as discussed in a World Report in this issue, and further adaptations can be expected. The mutations of H7N9 virus might not be controllable, but China's efforts to track and contain the outbreak of H7N9 can be managed and monitored.

As for SARS's legacy, China is now better prepared to deal with the H7N9 outbreak. The Chinese Government's response to H7N9 has been much swifter and more transparent than it was in the SARS outbreak, which has earned praise from the international community. “We are very satisfied and pleased with the level of information shared and we believe we have been kept fully updated on the situation”, said Michael O'Leary, WHO's representative in China. Having boosted investment enormously in the public health system since SARS, China has established and strengthened national and local surveillance systems to prevent and control diseases and has also expanded its laboratory capacity. Additionally, China's collaboration and communications with WHO and international scientific communities have been increased and strengthened.

The national and provincial government response, however, is not without controversy. There is debate within the Chinese news media and among the public that Shanghai might have deliberately delayed reporting cases of H7N9 human infection. The first infection in man was identified on Feb 19, but no public announcement was made until March 31. Treatment strategies against H7N9 virus infection are also being questioned. Chinese Government officials have suggested that people try the unproven indigowoad root (known as banlangen in Chinese) to prevent H7N9 virus infection. Furthermore, the efficacy of peramivir injection to treat H7N9 infection is as yet unclear, but this antiviral drug received accelerated authorisation on April 6 by the China State Food and Drug Administration to treat H7N9 human infection. Another weak link lies in China's agricultural departments. Unlike people, poultry infected with H7N9 virus show few symptoms, making detection very challenging. Health officials have acted promptly upon laboratory confirmation of cases, but can agricultural officials catch up with speed tracing to identify the animal origins of H7N9 virus?

China is once again back in the spotlight with the H7N9 virus outbreak, which will be a test not only for its health and agricultural systems, but also for its political system, and for the new Minister of Health, Li Bin. H7N9 presents China with the opportunity to prove its openness and ability to rapidly share information from its well-developed surveillance system and strong research capacity.