May 31, 2013 (CIDRAP News) – Local emergency responses to H7N9 influenza outbreaks in China have all ended, a Chinese media report said today, as the World Health Organization (WHO) released an overview of what has been learned about the virus and the disease since it emerged 2 months ago.
All the areas of China affected by the virus had ended their emergency responses as of May 28, according to a report today from the Chinese news agency Xinhua (via China Daily).
"The epidemic will be under routine monitoring as it has been deemed controllable and there has been no evidence of human-to-human transmission," the story said.
Shanghai, the city where one of the first H7N9 cases was identified on Mar 31, was the first jurisdiction to call off its emergency response, on May 10, and Zhoukou city in central China's Henan province was the last, Xinhua said. Ten provinces and cities had cases.
The newest case in the outbreak was reported May 28 in a 6-year-old Beijing boy, after 20 days with no new cases. A total of 132 cases and 37 deaths have been tallied since the outbreaks began.
Another Xinhua story today said the Beijing boy was released from a hospital after he tested negative for the virus. The story said he had been hospitalized "for medical observation and treatment" after his infection was confirmed.
Also today, the WHO released "Overview of the emergence and characteristics of the avian influenza A(H7N9) virus," summarizing information about the virus in 8 pages of text and about 30 pages of charts and other materials.
Among other things, it notes that the median age of patients is 61, with males outnumbering females by 2.4 to 1. Following are some other points made in the report:
- There have been four clusters of two or more case-patients who were in close contact, meaning that limited human transmission can't be ruled out, though most patients had no known exposures to other patients.
- Complications of the infection have included septic shock, respiratory failure, acute respiratory distress syndrome, refractory hypoxemia, acute renal dysfunction, multiple organ dysfunction, rhabdomyolysis, encephalopathy, and bacterial and fungal infections.
- The median time from illness onset to death has been 11 days.
- Testing of tens of thousands of samples from poultry and their environments, mostly from live bird markets, have yielded 51 H7N9 isolates.
- Tests found no H7N9 in thousands of respiratory and serologic samples from swine farms and slaughterhouses in three provinces and Shanghai.
- Several candidate vaccine viruses have recently been made available to manufacturers.
- Although newer vaccine technologies such as cell-culture production and recombinant hemagglutinin may be used, "it will probably be many months before large quantities of a vaccine are available."
May 31 China Daily story about emergency responses
May 31 Xinhua story on release of Beijing boy from hospital
May 31 WHO overview of H7N9