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Influenza Update USA and Europe

Monday, December 31, 2012 // Uncategorized

From ProMED Digest.  It certainly fits with my observations

INFLUENZA – (116): (USA), EARLY START
*************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Sat 29 Dec 2012
Source: The Washington Post, Associated Press report [edited]
<http://www.washingtonpost.com/national/health-science/early-flu-season-could-be-severe-experts-warn/2012/12/29/9ae51816-5045-11e2-839d-d54cc6e49b63_story.html?wpisrc=nl_headlines>

The flu season in the United States is having its earliest start in
nearly a decade, and health officials say this season [2012-2013]
could be a bad one. Although flu is always unpredictable, the early
nature of the cases and the predominant type circulating this year
[2012] could make this a severe flu season, said officials at the
Centers for Disease Control and Prevention [CDC]. But officials said
the vaccine formulated for this year is well-matched to the strains of
the virus seen so far and urged those who have not been vaccinated to
get a flu shot.

In early December 2012, the CDC said it was noticing an increase in
flu activity about a month before authorities normally see it, and the
earliest since the 2003-2004 flu season. The primary strain this
season is H3N2, an influenza A virus that has been associated in the
past with more severe flu seasons.

Since the beginning of December [2012], “there has been increasing
influenza activity in more parts of the United States and more cases
of flu,” said Joe Bresee, chief of epidemiology at CDC’s influenza
division, in an interview last week. “We have seen increasing trends
that flu is increasing in the last few weeks of the year, and I
wouldn’t be surprised if we see that continue into the new year.”
Influenza often peaks in January, February or even later.

Reports of flu have been reported in 29 states, including Maryland and
Virginia. As of 15 Dec 2012, higher-than-normal reports of flu-like
illnesses had been reported in 12 states, most of them in the South
and Southeast. They are: Virginia, Alabama, Georgia, Louisiana,
Mississippi, Missouri, North and South Carolina, Tennessee, Texas,
Illinois and Utah.

Based on data from the past 2 decades, during the years when H3N2 is
the predominant flu strain, “there are more deaths and
hospitalizations,” Bresee said. It is not completely clear why. One
factor may be that the elderly, who are at high risk for flu
complications, tend to become sicker with the H3N2 strain than the
other 2 common flu strains, he said.

But this flu season offers 2 bits of good news as well. Of the flu
strains that are spreading this year [2012], about 80 percent are the
influenza A type, and almost all of those are the H3N2 strain, Bresee
said. That matches well with this year’s flu vaccine, which includes
the H3N2 strain. Flu vaccines are designed to protect against 3
influenza viruses that experts predict will be the most common during
the upcoming season. The 3 kinds of influenza viruses that commonly
circulate among people today are influenza B, influenza A (H1N1), and
influenza A (H3N2). Each year, one flu virus of each kind is used to
produce seasonal influenza vaccine.

Also, the Food and Drug Administration on 21 Dec 2012 expanded the
approved use of Tamiflu [a neuraminidase inhibitor] to treat children
as young as 2 weeks old who have shown symptoms of flu. The drug was
previously approved to treat adults and children one year and older.
The dose for children under one year old must be based on their exact
weight.

Flu is extremely unpredictable. “You never know when the peak will
occur or how big the peak will be,” Bresee said. “If you’ve seen one
flu year, it’s just one flu year.” Last winter’s flu season
[2011-2012], for example, set a new record for the lowest and shortest
peak of influenza-like illness. The season began late and was mild
compared with most previous seasons. The last time a regular flu
season started this early was the winter of 2003-04, which proved to
be one of the deadliest seasons in the past 35 years, with more than
48 000 deaths. The dominant type of flu back then was the same one
seen this year [2012]. But experts said there is a critical difference
between then and now: In 2003-04, the vaccine was poorly matched to
the predominant flu strain. Also, health officials said more vaccine
is available now, and vaccination rates have risen for the general
public and for key groups such as children, pregnant women and
health-care workers.

About 112 million Americans had been vaccinated by the end of November
2012, the CDC said. Manufacturers were expecting to produce about 135
million total doses this year [2012]. Flu vaccinations are recommended
for everyone 6 months or older. On average, about 25 000 Americans die
each flu season, according to the CDC.

Flu usually peaks in midwinter. Symptoms can include fever, cough,
runny nose, head and body aches, and fatigue. Some people also suffer
vomiting and diarrhea, and some develop pneumonia or other severe
complications. A strain of swine flu that hit in 2009 caused a wave of
cases in the spring and then again in the early fall. But that was
considered a unique type of flu, distinct from the conventional
strains that circulate every year, experts said.

[Byline: Jacquelyn Martin]

– —
Communicated by:
ProMED-mail <[email protected]>

[There are distinctive differences in the characteristics of the early
phase of the northern hemisphere winter influenza epidemic between
North America and the European Region. In particular. Influenza
A/(H3N2) virus is not the predominant virus in the European Region.

According to the current EuroFlu – Weekly Electronic Bulletin (Week 5:
17/12/2012-23/12/2012, 28 Dec 2012, Issue N 468
<http://www.euroflu.org/cgi-files/bulletin_v2.cgi>): “Influenza
activity is slowly increasing with more countries in different parts
of the [European] Region reporting sporadic co-circulation of
influenza A(H1N1)pdm09, A(H3N2) and type B viruses. This week, the
reporting of influenza surveillance data is incomplete due to the
Christmas holidays. This is reflected in the lower number of tests
performed. However, the percentage of influenza-positive samples from
both sentinel and non-sentinel sources are similar to last week. The
number of reported hospitalisations due to severe acute respiratory
infection (SARI) remains similar to that seen in the previous several
weeks: One influenza detection was reported (influenza B). The number
of specimens testing positive for influenza decreased together with
the number of samples tested due to the relatively low reporting rate
by the countries in the western part of the region caused by holidays
this week. Overall, a total of 386 specimens tested positive for
influenza in week 51/2012: 275 were type A, and 111 were type B. Of
the influenza A viruses, 74 were subtyped: 38 as A(H3N2) and 41 as
A(H1N1)pdm09.” – Mod.CP

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