What is the case fatality rate (CFR) for H7N9?

Laidback Al · Apr 4, 2013

What is the CFR for H7N9?

It is not too early to start discussions about the case fatality rate (CFR) for the H7N9 virus. The case fatality rate is the number of individuals who die from a disease divided by the number of individuals infected with the disease.

Of the 14 confirmed cases, 6 are reported to have died and only 2 or 3 have recovered with the remainder still receiving treatment. Thus, the current CFR would be about .43 for these cases.

Like other outbreaks of novel diseases, it is not possible to know how many, if any, mild or asymptomatic H7N9 cases are being overlooked. If there are numerous mild infections, the CFR would decrease dramatically.

However, .43 is a very high CFR. For comparison, the 1918 pandemic was estimated to have a CFR of between .02 and .03. So, if this virus becomes easily transmissible and maintains its virulence, the world could be facing a dangerous pandemic.
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w

unctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w

oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

ontGrowAutofit/> <w:SplitPgBreakAndParaMark/> <w:EnableOpenTypeKerning/> <w

ontFlipMirrorIndents/> <w:OverrideTableStyleHps/> </w:Compatibility> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]-->

JimO · Apr 4, 2013

Re: What is the case fatality rate (CFR) for H7N9?

If the CFR was comparable to past human flu epidemics (0.02 to 0.03), then with 6 to 10 fatalities (assuming some have not been tested), then we should be seeing hundreds of cases. I suspect the Chinese government could be keeping that many cases quiet. So I would guess that it has a CFR similar to other serious human flu viruses.

Laidback Al · Apr 4, 2013

Re: What is the case fatality rate (CFR) for H7N9?

The situation of media reporting of recent H5N1 cases in Indonesia provides a counterpoint perspective to the media reports of H7N9 from China.

The case fatality rate of H5N1 cases in Indonesia between December 31, 2010 and January 1, 2013, is about 90% (.90). Only H5N1 deaths appear to be reported because suspicious deaths are highly visible in local communities. Additional testing might show more mild or asymptomatic human cases of H5N1, but I don't think Indonesia wants to be branded as the source of H5N1 if it goes pandemic.

It is possible that China is manipulating the media reports. But even China understands that it is very difficult to hide dead bodies from a watchful public. Until the Chinese start testing mild ILI cases for H7N9, it is hard to know how many people might be infected with H7N9. But at least China isn't only reporting fatalities from this new strain. In fact, at least one of the cases was reported while he was being hospitalized, and only dying after being publicly reported.
<object style="position:absolute;z-index:1000" type="application/x-dgnria" id="plugin0" height="0" width="0">

</object>

Giuseppe · Apr 5, 2013

Re: What is the case fatality rate (CFR) for H7N9?

Pure speculation:

-- A Chinese province with around 80,000,000 inhabitants:

-- A sporadic to regional activity;

-- An attack rate around 50%;

-- A weekly ILI number of cases around 250,000;

-- 25% requires hospitalization (50,000);

-- 10% has fatal outcome (5,000).

A conservative speculation would results in 5,000/10,000 deaths per week with fully sustained h2h transmission (AR 50%, like 1918, cfr 2%)....

What is the case fatality rate (CFR) for H7N9?

Laidback Al

Well-known member

JimO

Well-known member

Laidback Al

Well-known member

Giuseppe

Emeritus