Via CIDRAP, Lisa Schnirring writes: Officials report 2 more H7N9 cases, list deaths at 112. After describing the cases, she goes on to say:
China's government hasn't publicly released any overall H7N9 illness and death numbers since last spring, but it has kept Hong Kong's Centre for Health Protection and other groups updated on the number of infections and other details about the outbreak.
Groups including FluTrackers have kept a close count of the illnesses, but the number of fatalities is murky, because many of the patients have been hospitalized with severe pneumonia, with lengthy stays in intensive care units, which makes tracking outcomes difficult.
However, new information today on the number of cases and deaths came from three official sources. A report from the World Health Organization (WHO) said that, since February 2013, 355 cases with 112 deaths have been reported. The information was in a technical report that accompanied the WHO's recommendation on seasonal flu vaccine strains.
In addition, FluTrackers found reports in Chinese from the country's agriculture ministry and Xinhua, the state news agency, that listed the number of illnesses as 347 and put the number of deaths at 109.
Accurate numbers for illnesses and deaths are needed to calculate the case-fatality ratio (CFR), one measure health officials use to assess risk.
The European Centre for Disease Prevention and Control (ECDC) said in a Feb 7 risk assessment that the number of deaths in the H7N9 outbreak is not systematically reported to WHO or ECDC, but that at least 63 patients were known to have died. The ECDC put the CFR at 20.5%.
Using the WHO's numbers, the CFR would be about 31.5%, which is fairly close to the 28% CFR from last May as the first wave of infections was winding down, when China was reporting 132 cases and 37 deaths.
However, health officials recently urged caution in interpreting the CFR for the second wave, which initially seemed to be lower than during the first wave, because many of the patients were still hospitalized, some with severe infections.