Why the Flu Is the Smartest Virus Around (Huff Post)

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Influenza Virus: Why the Flu Is the Smartest Virus Around by

Norman H. Edelman, M.D. Posted: January 25, 2011.

Thousands of people around the world are diagnosed with influenza each year. [1]

Even more do not receive an official diagnosis, but still have what is commonly

known as " the flu. "

It often starts as a cough, sore throat, chills, fever, or even just aches, and

is easily confused with the common cold. [2] What many do not understand is that

the influenza virus is both a serious respiratory condition and one of the

" smartest " viruses around. [3]

The history of the influenza virus can be traced back more than 800 years.

Before 1932, when the virus was first identified in a laboratory, the virus's

progression was tracked by written histories of the disease symptoms. [4]

The first influenza epidemic was reported in 1173 CE. [5] The most recent

influenza pandemic was the H1N1 strain, which sickened millions and led to more

than 18,000 deaths globally in 2009-10. [6]

Although we generally refer today to a single influenza virus, there are

actually many forms of influenza virus, none of which are either the same virus

identified in 1932 or the virus our ancestors suffered from 800 years ago. While

all varieties of influenza are RNA-type viruses that attack the respiratory

system, the molecular biology of each virus mutates frequently, effectively

trying to " outsmart " those of us physicians and scientists who strive to keep

the virus at bay. [7]

So let's take a look at exactly what this ever-changing influenza virus really

is. There are three types of influenza viruses -- A, B and C. [1] Influenza A

and B viruses cause seasonal epidemics of disease almost every winter in the

United States. Influenza A is the most common and is a quickly mutating serotype

and is often more debilitating than the Influenza B virus. Influenza type C

infections cause a mild respiratory illness and are not thought to cause

epidemics. [1]

All three influenza viruses continually mutate to " trick " the body's immune

system. Each year, we develop antibodies against one strain of influenza but the

virus often changes the next year and leaves us at risk again. In some cases,

the antibodies developed from previous years may provide some protection against

the new influenza virus, but that is not a game of chance we want to take and

why there is a need of annual vaccination. [8]

As antiviral drugs are only effective if given early, it is more important to

vaccinate as many people as possible before the start of flu season. [9] Each

year, the World Health Organization's (WHO) scientists look at the influenza

viruses and predict which three, two influenza A and one influenza B viruses,

will be the most prevalent during the upcoming season. [10] Pharmaceutical

companies then develop vaccines that provide the most protection against those

predicted viruses.

Since influenza viruses are continually " drifting " by undergoing small changes

from one season to the next or even within the course of one flu season, it is

impossible to predict with complete certainty which influenza viruses will be

predominate or the severity, timing or duration of an influenza season. The

vaccine can cross-protect against circulating viruses. Antibodies created

through vaccination with one strain of influenza viruses will often offer

protection against different, but related strains of influenza viruses.

The influenza virus is easily transmitted from person-to-person and we all are

at risk for contracting influenza. For some, this will only mean lost work or

school days, but for those at highest risk, the results can be more serious,

leading to hospitalization and even death. Although sanitizing your home, work

and other spaces can slow the virus progression, vaccination is the optimal way

to prevent influenza outbreaks. [11, 12]

The U.S. Centers for Disease Control and Prevention (CDC) recommends annual

influenza immunization for everyone over six months of age. Groups at higher

risk of influenza infection or complications include [11]:

People 50 years of age and older

Children six months-18 years of age

Pregnant women

People of any age with certain chronic medical conditions, such as asthma,

chronic obstructive pulmonary disease (COPD), heart disease, diabetes and others

Residents of long-term care facilities and nursing homes

What puzzles many of us in the health care industry is that although protection

against the virus is a simple vaccination, influenza immunization rates fall far

short of public health goals every year -- even among those at highest risk.

Studies have shown that influenza outbreaks typically start in areas in which

the population has little or no immunity. This can be either because of a

mutation to the virus or, as with some developing countries or rural areas,

vaccination is sparse. [13]

Why are immunization rates for many groups low? Is it the product of complacency

in those who have never had influenza, or something else? Whatever the reason,

it is important to be vaccinated annually each flu season. Contrary to popular

belief, however, the vaccine may not make you sick. According to the CDC, it is

safe and effective. [11] If you do get sick immediately after receiving the

vaccine, it is likely that you either were exposed to the virus either before or

within two weeks after receiving the vaccine, when your body is building

immunity against the strains or that it was a new strain not accounted for in

the vaccine. [2, 14]

It is important to learn as much as you can about the seasonal influenza virus

and vaccine to protect yourself and your loved ones. The American Lung

Association's Faces of Influenza campaign is a great place to get educated and

find a location to get your influenza vaccine if you haven't already. It is

rarely " too late " to get vaccinated, as flu season usually lasts well into the

spring, with virus activity peaking in February or March in most years.

More knowledge about this serious illness is just one click away at

www.facesofinfluenza.org.

References

1 The Centers for Disease Control Keys Facts About Influenza and the Flu

Vaccine. Accessed December 20, 2010. http://www.cdc.gov/flu/keyfacts.htm

2 The Centers for Disease Control Keys Facts About Influenza and the Flu

Vaccine. Accessed December 20, 2010. http://www.cdc.gov/flu/keyfacts.htm

3 C.W. Potter, Division of Molecular and Genetic Medicine, University of

Shefield Medical School, Shefield, UK and Department of Pathology, Perak College

of Medicine, Ipoh, Perak Darul Ridzuan, Malaysia, Journal of Applied

Microbiology 2001, p. 572

4 C.W. Potter, Division of Molecular and Genetic Medicine, University of

Shefield Medical School, Shefield, UK and Department of Pathology, Perak College

of Medicine, Ipoh, Perak Darul Ridzuan, Malaysia, Journal of Applied

Microbiology 2001, p. 572

5 C.W. Potter, Division of Molecular and Genetic Medicine, University of

Shefield Medical School, Shefield, UK and Department of Pathology, Perak College

of Medicine, Ipoh, Perak Darul Ridzuan, Malaysia, Journal of Applied

Microbiology 2001, p. 574

6 World Health Organization Pandemic Update 112, August 2010. Accessed December

20, 2010. http://www.who.int/csr/don/2010_08_06/en/index.html

7 WHO position paper: influenza vaccines WHO weekly Epidemiological Record 19

August 2005, vol. 80, 33, pp.282. Accessed December 20, 2010.

http://www.who.int/wer/2005/wer8033.pdf

8 Medicine.net. Why Should the Flu Vaccine Be Taken Every Year. Accessed

December 20, 2010. http://www.medicinenet.com/influenza/article.html

9 The Centers for Disease Control, " Key Facts About Anitviral Drugs and

Influenza. Accessed December 20, 2010.

http://www.cdc.gov/flu/protect/antiviral/keyfacts.htm

10 World Health Organization, " Recommended Viruses for Influenza Vaccines for

Use in the 2010-2011 Northern Hemisphere Influenza Season. " Accessed December

20, 2010.

http://www.who.int/csr/disease/influenza/recommendations2010_11north/en/index.ht\

m

11 Centers for Disease Control and Prevention (CDC). Prevention and control of

influenza with vaccines: recommendations of the Advisory Committee on

Immunization Practices (ACIP), 2010. MMWR. 2010;59(RR-8):1-62.

12 Centers for Disease Control and Prevention. " How To Clean and Disinfect

Schools To Help Slow the Spread of Flu. " Accessed December 20, 2010.

http://www.cdc.gov/flu/school/cleaning.htm

13 Medicine.net. Why Should the Flu Vaccine Be Taken Every Year. Accessed

December 20, 2010. http://www.medicinenet.com/influenza/article.html

14 Holmes, E; Ghedin E, N, J, Bao Y, St K, Grenfell B,

Salzberg S, Fraser C, Lipman D, Taubenberger J (2005). " Whole-genome analysis of

human influenza A virus reveals multiple persistent lineages and reassortment

among recent H3N2 viruses " . PLoS Biol 3 (9): e300.

doi:10.1371/journal.pbio.0030300. PMID 16026181.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180517/?tool=pmcentrez

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