H1N1 virus : news you should know about

[Bronco Yoda]

INFLUENZA PANDEMIC (H1N1) 2009 (72): PNEUMONIA
**********************************************
A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases


[1]
Date: Fri 16 Oct 2009
Source: The Washington Post [edited]



Viral pneumonia commoner with swine flu than common flu
-------------------------------------------------------
The World Health Organization (WHO) on Friday [16 Oct 2009] urged doctors
to treat suspected swine flu cases as quickly as possible with antiviral
drugs, warning that the virus can cause potentially life-threatening viral
pneumonia much more commonly than the typical flu, sometimes in relatively
young, otherwise healthy people. "It's not like seasonal influenza," said
Nikki Shindo, a medical officer in the WHO's Epidemic and Pandemic Alert
and Response Department. "It can cause very severe disease in previously
healthy young adults." Shindo's comments came at the conclusion of a
special 3 day meeting in Washington of more than 100 experts from around
the world. WHO called the meeting to review the latest research on the new
H1N1 virus [the pandemic (H1N1) 2009 virus] and to revise guidelines for
treating the infection [see part [2] below}.

Unlike the seasonal flu, Shindo said, the virus appears more likely to
travel deep into the lungs, where it can cause viral pneumonia. Such a
condition can cause severe lung damage and a life threatening condition
known as acute respiratory distress syndrome. "Remarkably different is this
small subset of patients that presents very severe viral pneumonia," Shindo
said. Shindo noted that some hospitals in Australia and New Zealand were
severely strained by seriously ill swine flu patients during their recently
ended winter.

"This disease overwhelmed emergency rooms and especially intensive care
units because of the very severe patients that required special care,"
Shindo said, urging hospitals to prepare for the possibility of a
significant number of patients requiring intensive care. "We can expect
more severe disease during the upcoming influenza season," she said. Shindo
noted that, although a few cases have been reported of people who have been
infected with virus that is resistant to antiviral drugs, the medications
remain highly effective for most patients if administered quickly. "Do not
delay treatment," Shindo said. "Do not miss this opportunity for early
treatment."

WHO's warnings came as US health officials announced that the number of
states reporting widespread flu had increased from 37 to 41 and regional or
local outbreaks were being reported in the remaining parts of the country.
The number of deaths from pneumonia and flu-like illnesses had surpassed
what the federal Centers for Disease Control and Prevention (CDC) considers
an epidemic level, said Anne Schuchat of CDC. About 6 per cent of all
doctor visits are for flu-like illnesses, she said. "It's unprecedented for
this time of year to see the whole country seeing such high level of
activity," she said.

CDC also reported that vaccine production was proceeding slower than
officials had hoped, meaning less vaccine was probably going to be
available by the end of the month than originally projected. While
officials had hoped about 40 million doses would be available by the end of
October [2009], that would probably fall short by about 10 million to 12
million doses, Schuchat said. "We do still expect to have the large number
of doses," Schuchat said. "Eventually anyone who wants to be vaccinated
will be able to be vaccinated. But it's a slow start. We unfortunately
won't have as much by the end of this month as we had hoped." So far 11.4
million doses have become available and states have ordered about 8 million
doses, but large amounts of vaccine will not become available until
November [2009], she said.

The number of children and teenagers who have died from the disease
continued to mount, Schuchat said. At least 86 Americans younger than 18
have died from the disease, including 11 deaths that have been reported in
the past week. About half of the deaths that have occurred in the past
month were among teenagers, she said. Since 30 Aug 2009, 43 pediatric
deaths have been reported, including 3 in those younger than age 2; 5 among
those ages 2 to 4, 16 in those ages 5 to 11; and 19 among those ages 12 to
17, she said. "These are very sobering statistics," Schuchat said, noting
that only about 40 or 50 children die during an entire flu season. While
many of the deaths occurred among those with other health problems, some
occurred in children who were otherwise healthy, she said. "Every death we
take seriously, but as a society the deaths of children are very hard to
take," she said.

[byline: Rob Stein]

--
communicated by:
ProMED-mail


******
[2]
Date: Fri 16 Oct 2009
Source: World Health Organization (WHO), CSR [edited]



Clinical features of severe cases of influenza pandemic (H1N1) 2009 virus
infection
Briefing note 13
-------------------------------------------------------
To gather information about the clinical features and management of
pandemic influenza, WHO hosted a 3 day meeting at the headquarters of the
Pan American Health Organization in Washington DC, on 14 Oct 2009. Findings
and experiences were presented by around 100 clinicians, scientists, and
public health professionals from the Americas, Europe, Asia, Africa, the
Middle East, and Oceania.

The meeting confirmed that the overwhelming majority of persons worldwide
infected with the new pandemic (H1N1) 2009 virus continue to experience
uncomplicated influenza-like illness, with full recovery within a week,
even without medical treatment.

However, concern is now focused on the clinical course and management of
small subsets of patients who rapidly develop very severe progressive
pneumonia. In these patients, severe pneumonia is often associated with
failure of other organs, or marked worsening of underlying asthma or
chronic obstructive airway disease. Treatment of these patients is
difficult and demanding, strongly suggesting that emergency rooms and
intensive care units will experience the heaviest burden of patient care
during the pandemic.

Primary viral pneumonia is the commonest finding in severe cases and a
frequent cause of death. Secondary bacterial infections have been found in
about 30 per cent of fatal cases. Respiratory failure and refractory shock
have been the commonest causes of death. Presentations during the meeting
explored the pathology of severe disease in detail, with findings supported
by work in experimental animals. These findings confirm the ability of the
pandemic (H1N1) 2009 virus to directly cause severe pneumonia.

Participants who have managed such cases agreed that the clinical picture
in severe cases is strikingly different from the disease pattern seen
during epidemics of seasonal influenza. While people with certain
underlying medical conditions, including pregnancy, are known to be at
increased risk, many severe cases occur in previously healthy young people.
In these patients, predisposing factors that increase the risk of severe
illness are not presently understood, though research is under way. In
severe cases, patients generally begin to deteriorate around 3 to 5 days
after symptom onset. Deterioration is rapid, with many patients progressing
to respiratory failure within 24 hours, requiring immediate admission to an
intensive care unit. Upon admission, most patients need immediate
respiratory support with mechanical ventilation. Some patients do not
respond well to conventional ventilatory support, however, further
complicating the treatment.

On the positive side, findings presented during the meeting add to a
growing body of evidence that prompt treatment with the antiviral drugs,
oseltamivir or zanamivir, reduces the severity of illness and improves the
chances of survival. These findings strengthen previous WHO recommendations
for early treatment with these drugs for patients who meet treatment
criteria, even in the absence of a positive confirmatory test.

In addition to pneumonia directly caused by replication of the virus,
evidence shows that pneumonia caused by co-infection with bacteria can also
contribute to a severe, rapidly progressive illness. Bacteria frequently
reported include _Streptococcus pneumoniae_ and _Staphylococcus aureus_,
including methicillin-resistant strains in some cases. As these bacterial
co-infections are more frequent than initially recognized, clinicians
stressed the need to consider empiric antimicrobial therapy for community
acquired pneumonia as an early treatment.

Participants agreed that the risk of severe or fatal illness is highest in
3 groups: pregnant women, especially during the 3rd trimester of pregnancy,
children younger than 2 years of age, and people with chronic lung disease,
including asthma. Neurological disorders can increase the risk of severe
disease in children.

Evidence presented during the meeting further shows that disadvantaged
populations, such as minority groups and indigenous populations, are
disproportionately affected by severe disease. Although the reasons for
this heightened risk are not yet fully understood, theories being explored
include the greater frequency of co-morbidities, such as diabetes and
asthma, often seen in these groups, and lack of access to care.

Although the exact role of obesity is poorly understood at present, obesity
and especially morbid obesity have been present in a large portion of
severe and fatal cases. Obesity has not been recognized as a risk factor in
either past pandemics or seasonal influenza.

WHO and its partners are providing technical guidance and practical support
to help developing countries better detect and treat illness caused by the
pandemic virus. Patient care advice that can be applied in resource-limited
settings is being rapidly compiled.

--
communicated by:
a correspondent who has requested anonymity

[Most people worldwide infected with the pandemic (H1N1) 2009 virus
continue to experience uncomplicated influenza-like illness. But both
pneumonia directly caused by replication of the virus, and pneumonia caused
by co-infection with bacteria, can contribute to a severe rapidly
progressive sometimes fatal illness. Risk of severe or fatal illness is
highest but not exclusively so in 3 groups: pregnant women, especially
during the 3rd trimester of pregnancy, children younger than 2 years of
age, and people with chronic lung disease, including asthma. However, the
factors predisposing apparently healthy young people to severe disease have
yet to be defined. - Mod.CP]

[see also:
Influenza pandemic (H1N1) 2009 (71): case counts 20091017.3568
Influenza pandemic (H1N1) 2009 (70): Nepal 20091016.3563
Influenza pandemic (H1N1) 2009 (69): case management 20091013.353
Influenza pandemic (H1N1) 2009 (68): Viet Nam, virus clearance 20091011.3519
Influenza pandemic (H1N1) 2009 (67): vaccine delivery 20091011.3515
Influenza pandemic (H1N1) 2009 (66): case counts 20091010.3510
Influenza pandemic (H1N1) 2009 (65): update 20091009.3495
Influenza pandemic (H1N1) 2009 (64): Canada, vaccination update 20091005.3457
Influenza pandemic (H1N1) 2009 (63): USA military vaccine 20091002.3437
Influenza pandemic (H1N1) 2009 (62): Taiwan hosp cases 20091001.3421
Influenza pandemic (H1N1) 2009 (61): FLAARDS 20091001.3419
Influenza pandemic (H1N1) 2009 (60): bacterial coinfection 20090930.3410
Influenza pandemic (H1N1) 2009 (50): oseltamivir-resistance 20090917.3260
Influenza pandemic (H1N1) 2009 (40): global update 20090906.3138
Influenza pandemic (H1N1) 2009 (30): assumptions 20090813.2879
Influenza pandemic (H1N1) 2009 (20): Peru, 33 percent asymptomatic
20090730.2668
Influenza pandemic (H1N1) 2009 (10): vaccine 20090720.2577
Influenza pandemic (H1N1) 2009 - Viet Nam: patient data 20090708.2450]

************************************************** **********
Become a ProMED-mail Premium Subscriber at

************************************************** **********
Visit ProMED-mail's web site at .

################################################## ##########
################################################## ##########