Fall Predicition for Swine Flu

[Jori]

 

I came across this on another site.

It came from a news blurb about this fall's H1N1 prediction.

Basically, the experts are speculating it will be similar to the

1957 asian flu pandemic.

 

 

So here's a summary from Global Security:

 

 

In 1957, which was on the whole a much milder illness than that of

1918, the global death toll was estimated to be around 2 million. In

1957, the Asian flu pandemic resulted in about 70,000 deaths in the

United States. An excess 30,000 deaths occurred in England and Wales

of which 6,716 were ascribed to influenza itself. Estimates in the UK

ranged from 1.3 to 3.5 deaths/1,000 cases. An estimate from 29 British

general practices was 2.3 deaths per 1,000 cases attended.

 

 

In February 1957, the Asian influenza pandemic was first identified in

the Far East. Immunity to this strain was rare in people less than 65

years of age, and a pandemic was predicted. In preparation, vaccine

production began in late May 1957, and health officials increased

surveillance for flu outbreaks. The 1957 pandemic is instructive in

that the first US cases occurred in June but no community outbreaks

occurred until August and the first wave of illness peaked in October.

 

 

Unlike the virus that caused the 1918 pandemic, the 1957 pandemic

virus was quickly identified, due to advances in scientific

technology. The 1957 pandemic was associated with the emergence and

spread of the H2N2 virus [this virus subtype stopped circulating in

1968]. Vaccine was available in limited supply by August 1957. The

virus came to the US quietly, with a series of small outbreaks over

the summer of 1957. When US children went back to school in the fall,

they spread the disease in classrooms and brought it home to their

families. Infection rates were highest among school children, young

adults, and pregnant women in October 1957. Most influenza-and

pneumonia-related deaths occurred between September 1957 and March

1958. The elderly had the highest rates of death.

 

 

During the 1957-1958 pandemic, a WHO expert panel found that spread

within some countries followed public gatherings, such as conferences

and festivals.16 This panel also observed that in many countries the

pandemic broke out first in camps, army units and schools; suggesting

that the avoidance of crowding may be important in reducing the peak

incidence of an epidemic.

 

 

During the first wave of the Asian influenza pandemic of 1957-1958,

the highest attack rates were seen in school aged children. This has

been attributed to their close contact in crowded settings. A

published study found that during an influenza outbreak, school

closures were associated with significant decreases in the incidence

of viral respiratory diseases and health care utilization among

children aged 6-12 years.

 

 

In 1957, up to 50% of British schoolchildren developed influenza, but

even those schools which were severely disorganised had returned to

normal 4 weeks after the appearance of the first case. In residential

schools in the UK, attack rates reached 90%, often affecting the whole

school within a fortnight.

 

 

In Liverpool in 1957 12.6-19.4% of nurses were absent during the first

4 weeks of the epidemic; in one hospital, nearly a third were absent

at the peak. During September and October 1957, the two main months of

the epidemic in the UK, it was estimated between 25,000 and 30,000

more cases of acute respiratory infection were admitted to NHS

hospitals in England and Wales than would have been expected at that

time of year. Hospital admission and bed bureaux could barely cope

with the demand placed upon them.

 

 

In 1957, of patients with pneumonia studied mainly in London teaching

hospitals, 28% of those with staphylococcal pneumonia and 12% with non-

staphylococcal pneumonia died. The death rate among patients with

pneumonia fell during the course of the epidemic from around 20% to

13%. Deterioration can be very rapid and a high proportion of those

hospitalised who die, do so within 48 hours of admission, ie so

rapidly that antibiotics may have little or no effect.

 

 

Vaccine production for the Asian flu began about 3 months after the

first outbreaks occurred in China. The first cases in the US occurred

in the summer, with a peak in October following school openings. The

first doses of vaccine became available in September and by mid-

October at the peak of the US pandemic fewer than half of the

approximately 60 million doses produced had been delivered.

 

 

By December 1957, the worst seemed to be over. However, during January

and February 1958, there was another wave of illness among the

elderly. This is an example of the potential "second wave" of

infections that can develop during a pandemic. The disease infects one

group of people first, infections appear to decrease and then

infections increase in a different part of the population.

 

 

Other pandemics had a faster spread than in 1957, in general the

weekly profile for these pandemics had a higher peak and a shorter

base.

The conventional wisdom conveys China's Great Leap Forward famine as a

man-made disaster where misguided economic policies precipitated

widespread famine and world record-breaking population losses. Barbara

Sands reconstructed regional population and grain availability data to

find more complex patterns than those suggested by classic famine.

While allowing for considerable excess mortality in this period, she

suggested that portions of it were due to the influenza pandemic of

1957, an alternative explanation of the Great Leap Forward famine.