CDC: H1N1 could kill hundreds of thousands in the USA

[Siegfried X]

Swine flu could strike 40% in 2 years

U.S. health officials say swine flu could strike up to 40 percent of Americans over the next two years and as many as several hundred thousand could die if a vaccine campaign and other measures aren't successful.

Those estimates from the Centers for Disease Control and Prevention mean about twice the number of people who usually get sick in a normal flu season would be struck by swine flu. Officials said those projections would drop if a new vaccine is ready and widely available, as U.S. officials expect.

The U.S. may have as many as 160 million doses of swine flu vaccine available sometime in October, and U.S. tests of the new vaccine are to start shortly, federal officials said this week.

The infection estimates are based on a flu pandemic from 1957, which killed nearly 70,000 in the United States but was not as severe as the infamous Spanish flu pandemic of 1918-19. But influenza is notoriously hard to predict. The number of deaths and illnesses would drop if the pandemic peters out or if efforts to slow its spread are successful, said CDC spokesman Tom Skinner.

A CDC official said the agency came up with the estimate last month, but it was first disclosed in an interview with The Associated Press.

"Hopefully, mitigation efforts will have a big impact on future cases," Skinner said.

In a normal flu season, about 36,000 people die from flu and its complications, according to American Medical Association estimates. Because so many more people are expected to catch the new flu, the number of deaths over two years could range from 90,000 to several hundred thousand, the CDC calculated. Again, that is if a new vaccine and other efforts fail.

First identified in April, swine flu has so far caused about 263 U.S. deaths, according to the latest numbers. CDC officials say it's likely that more than 1 million Americans have become sick from the virus, although many were probably mild cases never reported.

Because the swine flu virus is new, most people haven't developed an immunity against it. So far, most of those who have died from it in the United States have had other health problems, such as asthma.

The virus has caused an unusual number of serious illnesses in teens and young adults; seasonal flu usually is toughest on the elderly and very young children.

New swine flu illness have erupted through the summer, which is also unusual, though cases were less widespread this month. Officials fear an explosion of cases in the fall, when children return to school and the weather turns cold, making the virus easier to spread.

 

[Vibrant62]

Re: CDC: H1N1 could kill hundreds of thousands in the USA

An interesting question for everyone. How many people do not consult a doctor when they have normal seasonal flu, or even in the past pandemics where the inidividual flu was mild? Did caclulations of CFR in the past take note of these mild cases who self treated? I suspect that, like now, only those cases that were sufficiently ill to seek medical advice are recorded.

A recent news report from NZ based on a study indicated that the CAR was close to 79% (based on test results), but that only half of these cases went on to be symptomatic at all. If true it could be that CARs are generally far higher than recognised, so that the 30% CAR estimate of past pandemics only picked up the symptomatic cases.

If we accept such a principle (that generally CAR is underestimated due to high levels of very mild cases in the community) then comparison of past case numbers based on presentation to doctors and relative hospitaliation rates should hold reasonalbly well for comparison with the present pandemic.

Thoughts anyone?

 

[Mamabird]

Re: CDC: H1N1 could kill hundreds of thousands in the USA

There are generally two indices discussed with respect to influenza. Clinical infection rates and case fatality factors.

The first is a percetage of the population that presents with infection that is clinically categorized as influenza. During flu season, that may range from 5 to 15% of the total population. If you do not go to the doc, you don't get counted.

Case fatality factor is the percentage of clinical infections that lead to death. That may be close to .2% of diagnosed illnesses during the typical flu season.

So, with a US population of say 300 million, you could expect approximately 20 million to be clinically diagnosed with influenza during the normal season, with maybe 40,000 never recovering.

Swine flu is differenct than seasonal flu. It has a higher clinical infection rate, but a lower case fatality factor. But, like people with seasonl flu, there are many, many people with swine flu that do not see a doctor or seek medical attention as their symptoms are not serious enough to warrant.

 

[BioSafeT]

Re: CDC: H1N1 could kill hundreds of thousands in the USA

Calculating the CAR/CFR today is pretty much an exercise in futility, because we don't have accurate numbers.

There is a large "uncounted" population that had a very mild case, never consulted a doc and never got tested/confirmed. That could be a good thing.

Thus it is also possible that there have been a number of deaths, directly attributable to H1N1, but which didn't get reported either. Deaths masquerading as meningitis, COPD, septicemia, toxic shock, seizures.

We have a couple of good historical points that tell us the next wave will be MUCH longer and MUCH more severe...and some of the most severely ill may be those who were primed by a mild infection in the hearld wave.

That large "uncounted" population is starting to look less and less like a good thing.

Now factor in that the virus may shift/drift/mutate into something more efficient/more virulent.

No matter how you slice this pie graph...the North American autumn is looking pretty ugly.

 

[Mamabird]

Re: CDC: H1N1 could kill hundreds of thousands in the USA

Calculating the CAR/CFR today is pretty much an exercise in futility, because we don't have accurate numbers.

There is a large "uncounted" population that had a very mild case, never consulted a doc and never got tested/confirmed. That could be a good thing.


No matter how you slice this pie graph...the North American autumn is looking pretty ugly.

It is fairly clear that over the years we were never privileged with accurate numbers when it comes to influenza. There is just always a large number of "uncounted" population that never seek medical attention. In that regard, Swine Flu is no different than Seasonal Flu.

I sense that most agree that this fall is looking pretty ugly with respect to the number of Swine Flu infections, with a large percentage of the population getting sick. I think there is considerable debate, however, as to the number of deaths. To date, with everyone being very attentive to the Swine Flu problem, there have been about 1,000 deaths world wide. In a typical flu season in the US, there may be as many as 40,000 deaths. So, unless this virus changes its stripes, a lot of kids will get sick with the Swine Flu, but most should recover without medical attention.