Common flu: Influenza

(Survival manual/6. Medical/ b) Disease/ Common flu-Influenza)

The Flu Season
In the Northern hemisphere, winter is the time for flu. In the United States, the flu season can range from November through March, and even past March in some years. During the past 21 flu seasons, months with the heaviest flu activity (peak months) occurred in December in 4 years, January in 5 years, February in 9 years, and March in 3 years.

Note: Flu virus cannot live over 1 hour outside a human host.

Symptoms
If you get infected by the flu virus, you will usually feel symptoms 1 to 4 days later. You can spread the flu to others before your symptoms start and for another 3 to 4 days after your symptoms appear. The symptoms start very quickly and may include:
•  Body aches
•  Chills
•  Dry cough
•  Fever
•  Headache
•  Sore throat
•  Stuffy nose

Typically, the fever begins to decline on the second or third day of the illness. The flu almost never causes symptoms in the stomach and intestines. The illness that some call “stomach flu” is not influenza.

Influenza Symptoms: What to Expect
•  Fever over 102°: Fever generally lasts 3-5 days, and is often higher in the afternoons and evenings, with some decrease in the mornings. Fever typically runs higher in children and can be over 104°.
•  Cough: The cough starts as dry and hacking and progresses by the 3rd day to wet with thick mucous. The cough can worsen for the next 4-7 days and could last for over 2 weeks. This is the major symptom of influenza. Cough in children can be croupy and serious. Smokers are at risk for significant bronchitis and pneumonia.
•  Headaches and Muscle Aches: These can be severe for the first few days and will slowly improve.
•  Fatigue: Fatigue is common and severe, lasting for 1-3 weeks.
•  Sore Throat: Sore throat is most common in older children and adults. It can be severe for the first few days.
•  Nasal Congestion and Red Eyes: Nasal congestion lasts for 1-2 weeks, and eyes may be red for 3-4 days.
•  Vomiting or Diarrhea (in children less than 6 years of age):  Vomiting or diarrhea is unusual in adults. These symptoms are typically seen in children less than 6 years of age and last for the first few days. [If vomiting is present see post, ‘Stomach flu: gastroenteritus’]
•  Influenza is typically contagious for 5-7 days from fever onset.
•  Influenzas tend to kill most of their victims in two ways: dehydration and lung congestion. Even the Avian flu, which is respiratory usually starts with stomach flu symptoms. Stomach flus usually induce diarrhea which rapidly dehydrates the victim.

WhatYou Should Do If You Get the Flu
•  Rest
•  Drink plenty of liquids, have  Gatorade in stock for rehydration and cut 50% with water to reduce sugar content which exaberates diahhrea.
•  Avoid using alcohol and tobacco
•  Take medication to relieve the symptoms of flu

Homemade Oral Rehydration Solution
influenza’s tend to kill most of their victims in two ways: dehydration and lung congestion. Even the Avian flu, which is respiratory usually starts with stomach flu symptoms. Stomach flus usually induce diarrhea which rapidly dehydrates the victim. To fight this, you need to stock up on both anti-diarrhea medicines (such as Imodium AD–an anti-spasmodic) and electrolyte solutions such as Pedialyte. (The latter is available in bulk though large chain “warehouse” stores.) The various sports type drinks (such as Gatorade) can be used as oral rehydration solutions (ORSs) too.
However dilute them about 50% with water, they have a lot of glucose in them which will exacerbate diarrhea symptoms.

If commercial oral hydration solutions are not available, I have read that you can make an emergency
solution as follows:
•1/2 teaspoon of salt
•2 tablespoons honey, sugar, or rice powder
•1/4 teaspoon potassium chloride (table salt substitute)
•1/2 teaspoon trisodium citrate (can be replaced by baking soda)
•1 quart of clean water

Items to have on hand at home
•  Imodium is a trade name for Loperamide. It can be purchased generically for relatively little cost, at such places as warehouse stores. The generic (house brands) are just fine.
•  Stock up on Acetominophen (Tylenol) and Ibuprofen (Motrin) as well – for treating fevers. These two antipyretics can be taken together or on an alternating 4 hour schedule (take each every 4 hours but split them, for example at 8 AM take acetaminophen, at 10 AM take ibuprofen, etc. This makes it easier to monitor the patient and get them to drink fluids, if they’re up every 2 hours they will have to drink some fluids).
•  Either have a traditional glass thermometer for each person, or a digital thermometer with lots of disposable sleeves. The thermometers are a couple of bucks at most drug stores. The sleeves are a buck or so per hundred. Don’t cross-contaminate your patients.
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Notes regarding Chills
·  Chills: Chills are usually present at the beginning of an illness and often precede a fever. This rapid muscle contraction and relaxation are the body’s way of trying to generate heat. Illnesses that cause chills include influenza, strep throat, gastroenteritis (bacterial or viral) and meningitis.
·  Shaking: Shaking and goose bumps may occur when an illness is present or when an individual is exposed to a cold, as this is the body’s way to try to get warm. Shaking often occurs when a fever is present.
·  Treatment: The treatment for illnesses that produce chills, shaking and nausea is fever reduction and drinking plenty of fluids to avoid dehydration. It is important to replace electrolytes that are lost due to fever, and if nausea is persistent there are several medications that may be prescribed by a doctor that may help relieve it.

Flu Vaccine
The main way to keep from getting flu is to get a yearly flu vaccine. You can get the vaccine at your doctor’s office or a local clinic, and in many communities at workplaces, supermarkets, and
drugstores. You must get the vaccine every year because it changes.

Scientists make a different vaccine every year because the strains of flu viruses normally change from year to year. Nine to 10 months before the flu season begins, they prepare a new vaccine made from inactivated (killed) flu viruses. Because the viruses are killed, they cannot cause infection. The vaccine preparation is based on the strains of the flu viruses that are in circulation at the time. It includes those A and B viruses (see section below on types of flu viruses) expected to circulate the following winter.

Sometimes, an unpredicted new strain may appear after the vaccine has been made and distributed to doctor’s offices and clinics. Because of this, even if you do get the flu vaccine, you still may get infected. If you do get infected, however, the disease usually is milder because the vaccine still will give you some protection.
• The influenza virus usually change & mutate every year.
• These changes cause seasonal flu epidemics.
• These changes mean that the flu vaccine must be reformulated annually.

Arguments for getting a flu shot
1)     The vaccine is only about 70 percent effective to begin with – and that’s in a good year, when the vaccine is well-calibrated to circulating strains. That’s not good enough to protect the U.S. population for one year, let alone two, CDC officials say.
2)     But the main argument now is one of waning immunity. CDC officials believe that a year after someone gets the flu shot, antibody levels can fall by 66% or more; the resulting levels are not strong enough to be protective.

Vaccine recommendations
If you are in any of the following groups or live in a household with someone who is, CDC recommends that you get the flu vaccine.
•  You are 50 years of age or older
•  You have chronic diseases of your heart, lungs, or kidneys
•  You have diabetes
•  Your immune system does not function properly
•  You have a severe form of anemia
•  You will be more than 3 months pregnant during the flu season
•  You live in a nursing home or other chronic-care housing facility
•  You are in close contact with children 0 to 23 months of age

Medicine for Prevention
Although the flu vaccine is the best way to prevent getting the flu, three antiviral medicines also are available by prescription that will help prevent flu infection.
•  Tamiflu (oseltamivir)
•  Flumadine (rimantadine)
•  Symmetrel (amantadine)

Tamiflu is for use in adults and teenagers 13 years and older. Rimantadine and amantadine may be used by adults and children who are 1 year of age and older.
•  These medicines help prevent the flu if you take them for at least 2 weeks during the outbreak of flu in your community.
•  You may use these medicines if you are in close contact with family members or others who have the flu.
•  You may use them if you are in close contact with people who have been vaccinated but whom you want to give added protection from getting the flu.
•  You may use either medicine immediately following flu vaccination during a flu epidemic to protect you during the 2- to 4-week period before antibodies (proteins from your immune system that protect you from the flu virus) develop or when a flu epidemic is caused by virus strains other than those covered by the vaccine.

Flumadine and Symmetrel have unpleasant side effects. Your health care provider can help you decide which medicine is best for you. You should discuss the flu vaccine and medicines with your health care provider before the flu season begins.

Types of Flu viruses
The first flu virus was identified in the 1930s. Since then, scientists have classified flu viruses into types A, B, and C.
•  Type A is the most common and usually causes the most serious epidemics
•  Type B outbreaks also can cause epidemics, but the disease it produces generally is milder than that caused by type A
•  Type C viruses, on the other hand, never have been connected with a large epidemic

Q&A
1.  Does getting vaccinated against flu early in the season pose a risk that immunity may wane before the end of the season?
No. Flu vaccination provides protection against the influenza strains contained in the seasonal vaccine for the entire season. Vaccination can begin as soon as vaccine becomes available.
2.  Is it too late to get vaccinated after Thanksgiving (or the end of November)?
No. CDC recommends that providers begin to offer seasonal influenza vaccination as soon as vaccine
becomes available in the fall, but if you have not been vaccinated by Thanksgiving (or the end of November), it can still be protective to get vaccinated in December or later because influenza disease usually peaks in January or February most years, and disease can occur as late as May.
3.  Does flu vaccine work right away?
No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection. In the meantime, you are still at risk for getting the flu. That’s why it’s better to get vaccinated early in the fall, before the flu season really gets under way.
4.  Can I get seasonal flu even though I got a flu vaccine this year?
Yes. The ability of flu vaccine to protect a person depends on two things: a) the age and health status of the person getting vaccinated, and b) the similarity or “match” between the virus strains in the vaccine and those circulating in the community. If the viruses in the vaccine and the influenza viruses circulating in the community are closely matched, vaccine effectiveness is higher. If they are not closely matched, vaccine effectiveness can be reduced. However, it’s important to remember that even when the viruses are not closely matched, the vaccine can still protect many people and prevent flu-related complications. Such protection is possible because antibodies made in response to the vaccine can provide some protection (called cross-protection) against different, but related strains of influenza viruses.
5. Why do I need to get vaccinated against the flu every year?
Flu viruses change from year to year, which means two things. First, you can get the flu more than once during your lifetime. The immunity (natural protection that develops against a disease after a person has had that disease) that is built up from having the flu caused by one virus strain doesn’t always provide protection when a new strain is circulating. Second, a vaccine made against flu viruses
circulating last year may not protect against the newer viruses. That is why the influenza vaccine is updated to include current viruses every year.Another reason to get flu vaccine every year is that after you get vaccinated your immunity declines over time and may be too low to provide protection after a year.

Pasted from <http://www.cdc.gov/flu/about/qa/fluvaccine.htm>