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2012/2013 Flu Update

Situational Update #1 Week of Nov 21 to Dec 1, 2012

Our coverage of influenza and influenza like illness begins this week. We'll continue weekly updates throughout the season season.

Influenza season starts about this time of year with a peak usually seen in early February. During an average flu season in the United States there are 35,000 to 45,000 deaths attributed to seasonal flu. Those most at risk of serious illness or death from seasonal influenza include people with severe medical conditions, impaired immune systems, or extremes of age young or old. Although vaccine remains the mainstay of flu prevention, proper use of personal protective equipment (PPE) and other non-pharmacological interventions can’t be ignored.

Review: Types of influenza
Influenza virus belongs to the category of diseases known as Orthomyxoviruses and is divided into three types(Type A, B,  and C). Type A influenza is the variety that causes us the most concern for mutation and has the largest possibility for creating a pandemic situation. Type A influenza is also the one we hear described by a combination of letters and numbers; H1N1, H5N1 for example. The “H”, more precisely HA, stands for hemagglutinin and “N” (NA) indicates neurominidase. Hemagglutinin and Neurominidase are proteins that allow the flu virus to enter a host cell, reproduce, and get out of the host cell. Some of the most promising medications used to fight influenza are Neurominidase inhibitors (NI). Tamiflu is a NI that has been widely used to treat flu and has recently come under concern as flu becomes resistant. There are 15 different types of HA and nine types of NA giving us a total of 135 potential combinations of type A influenza. The seasonal flu vaccine contains only two of those combinations. Hopefully they are the two most prevalent circulating strains.

Type B influenza is seen mostly in humans and although it's very common it is much less severe than Type A influenza. Type C influenza infects humans and swine and has a completely different pattern of surface proteins. Normally Type C presents with rare occurrences and has mild or no symptoms. In fact, by age 15 most people have antibodies against Type C influenza.

Mandate or not? There has been a lot of discussion on the topic of mandated flu vaccine with many opinions and views, but few conclusions. Many healthcare institutions have adopted a mixed program that requires vaccine or signing a declination form. There may be increased PPE use requirements for those who choose not to take the vaccine.  Unprecedented reports have begun to question the validity of seasonal flu vaccine. A CIDRAP report  suggested that vaccine actually had limited protection for young/middle age and only modest protection > 65. Tamiflu concerns have also been in the news with some accusing Roche Pharmaceuticals of withholding data relating to increased flu resistance with Tamiflu  use.

The media and public may not fully understand the terms used in biologic/pandemic situations. Simple working definitions can be easily explained to the public, increase understanding and decrease anxiety.
Isolation - People who are sick are kept away from those who are not.
Quarantine - People who are not sick, but may have been exposed, are kept apart from others until the incubation period passes.
Social Distancing - A term that can mean anything from not shaking hands or hugging, maintaining a distance of 3 to 6 feet away from others, up to staying home when you’re sick. Social distancing can be used to describe extreme recommendations that include school closure. “Snow day” is a term that is sometimes used to describe a period when everybody stays home to decrease the spread of disease.
Pandemic refers to a disease that has spread to a large number of people over a large (national or global) geographical area. Pandemic is not synonymous with large numbers of fatalities.

Non Pharmacological Interventions
NonPharm practices can save the day. If used properly they can be vital in curbing the spread of disease. The non pharmacological interventions of hand hygiene, respiratory etiquette, and appropriate social distancing should be used in any actual or suspected case of Influenza Like Illness (ILI). The key to personal protective equipment or PPE - is using it correctly. Routine practice makes perfect when it comes to PPE and may be more important than annual testing.

On the Web
Centers for Disease Control Flu CDC Flu
CDC weekly flu report
Center for Infectious Disease Researsh and Policy CIDRAP
American Journal of Infection Control AJIC
Google Flu Trends

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