Tracking US Deaths versus Deaths in the Healthy

Much is made in official pronouncements as well as in the media about how much increased risk of severe illness and death there is from people who have pre-existing medical conditions if they also contract swine flu. That might be true with seasonal human influenzaviruses. Problem is, this is not a human influenzavirus.

In the US, seasonal influenza is said to kill 36,000 people every year (need source), of which roughly 90% are elderly. It is already borne out by the CDC and the WHO that deaths from swine flu are much higher in the young category than is typical in flu season.

Data from the US also show an increase in deaths from the healthy. I have put together a Google spreadsheet tracking US deaths over time as well as the percentage of total deaths that are in people who do not have underlying medical conditions.

There are some problems with this. I used as the source for my data a different spreadsheet mentioned in a thread on flutrackers.com. (link to original needed) It seems rather complete. The issue is that firm death dates are not given. When no death date was given I tried to use the lag time from other reports from that state to determine where to set a death date. If I couldn't make a determination, I made an assumption of 3-4 days lag. So other people might come up with slightly different graphs, but the trend and final number should be a good match.

To determine if a person was healthy I looked at the remarks. A null comment is assumed to be healthy. If an underlying condition is marked disputed I assumed a healthy individual. Given the risks of pregnancy in this pandemic I assumed pregnancy to be a valid underlying condition.

Here is my spreadsheet:


And here is a chart showing the increase in the death rate in healthy individuals:



There is clearly an upward trend, and we may soon break 50% of all US deaths being from healthy individuals. It is probably true that an elderly person (who is most at risk from seasonal flu) has one or more underlying conditions, so the deaths that made up that graph are probably in young and middle aged people.

Rapid onset of symptoms and Death

There was recently a discussion on the Rhizalabs Flutracker message board about the recent (as of mid-June) spate of rapid deaths in young, healthy people. I posted an explanation of why viral pneumonia from influenza seems to cause rapid onset of illness and death (often less than 24 hours) versus more "normal" bacterial pneumonia triggered deaths. This was apparently a well-received explanation as it was requested I repost it periodically. I am posting it here so I can have easy access to it. Note there may be some finer technical details that are off, but I believe this is largely good enough for the layman.

From various things I have read it seems the immune system treats a viral infection of the lungs much differently than it does a bacterial infection. Normally, your immune system has to fight off bacteria by having certain types of immune cells eat (phagocytose?) the organism. This can be done without the the extremely lethal parts of the immune system.

But a virus enters the cell and hijacks the internal mechanisms in order to make more virions. The body must kill parts of itself, either by triggering the infected cell to die (apoptosis?) or outright killing it. Whena virus infects the lungs the body has to mount an attack with essentially its full arsenal. This leads to a cascade that can result in, as I understand it, the spongy material of the lungs being transformed into scar tissue.

The progression is viral pneumonia -> cytokine storm -> ARDS -> (multiple organ failure?) The cytokine storm is a result of the viral pneumonia and ARDS and multiple organ failure are the consequences of the cytokine storm. This all happens very quickly.

Bacterial pneumonia takes advantage of the weakness in the body generated by the viral infection, and typically takes longer to develop. This is the cycle of being sick, getting better, then taking a turn for the worse.

Are we reliving 1918?

I am a member of FluTrackers where my name is wotan. Several weeks ago I started this thread:

I have been reading John Barry's The Great Influenza, and have been struck by a few things. First, I was aware that the first wave in the spring of 1918 was considered mild, but I did not realize the following:

The first wave (assuming it started in Haskell County, KS, which Barry says is more or less impossible to determine) appeared to be slightly more severe in the very beginning, but it was a slightly less severe variant that got out. Compare with Mexico, although I am not entirely convinced that the increased mortality in Mexico was due to anything more than not knowing to use Tamiflu in the early days of the outbreak.

Symptoms from the first wave were so light (apparently less than seasonal flu) that the disease could be mistaken for something else entirely. We have seen anecdotal evidence of swine flu being mistaken for any number of other conditions.

The first wave persisted in the northern hemisphere into August. Obviously, we are still in it here at the end of May.

There were isolated incidences of more severe disease during the first wave. There is at least some anecdotal evidence to support this in the current outbreak as well.

I'm still fairly early into the second wave in the book, so I don't know what else I will find.

Sadly, the parallels continue. Consider for a moment the demographics attacked by the 1918 Spanish Flu:

The unusually severe disease killed between 2 and 20% of those infected, as opposed to the more usual flu epidemic mortality rate of 0.1%.[9][12] Another unusual feature of this pandemic was that it mostly killed young adults, with 99% of pandemic influenza deaths occurring in people under 65, and more than half in young adults 20 to 40 years old.[23] This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70), and may have been due to partial protection caused by exposure to a previous Russian flu pandemic of 1889.[24]

Source: Wikipedia

Now, consider the demographics for the 2009 pandemic so far:

57% of the cases that we're having reported to us occur in people 5 to 24 years of age, and 41% of the hospitalizations are in that same age group -- the older children and young adults. But I also want to tell you about the rates, the cases per 100,000 population, and let you know that the highest rates of hospitalization are actually in children under 5. And the next highest rates are in those people 5 to 24. So it looks like this is a virus that's disproportionately affecting younger people but there are still lots of infections and hospitalizations in older persons.

Source: Flutracker's post of CDC transcript.


Let's make this clear. Seasonal flu disproportionately attacks the elderly. The 2009 pandemic flu attacks the young! The 1918 pandemic flu attacks the young!

Will the 2009 pandemic grow as severe as 1918? Probably not, but that it might is the scary thought.