Influenza Season 2009–2010

The flu is a contagious illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccination each year.

The symptoms of influenza include:

• Fever (usually high)

• Headache

• Extreme tiredness

• Dry cough

• Sore throat

• Runny or stuffy nose

• Muscle aches

• Stomach symptoms, such as nauseas, vomiting, and diarrhea, also can occur but are more common in children than adults.

Flu viruses mainly spread from person to person through coughing or sneezing of people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose. Most healthy adults may be able to infect others beginning one day before symptoms develop and up to five days after becoming sick. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick.

Yes. Complications of the flu can include bacterial pneumonia, ear infections, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.

The single best way to prevent the flu is to get vaccination each year. There are two types of vaccines:

• The “flu” shot- an inactivated vaccine (containing killed virus) that is given with a needle. The flu shot is approved for use in people 6 months of age and older, including healthy people and people with chronic medical conditions.

• The nasal-spray flu vaccine- a vaccine made with live, weakened flu viruses that do not cause the flu, (sometimes called LAIV for “Live Attenuated Influenza Vaccine.” LAIV is approved for use in healthy people 2-49 years of age who are not pregnant.

About two weeks after vaccination, antibodies develop that protect against influenza virus infection. Flu vaccines will not protect against flu-like illnesses caused by non-influenza viruses.

Yearly flu vaccination should begin in September or as soon as vaccine is available and continue throughout the influenza season, into December, January, and beyond. This is because the timing and duration of influenza seasons vary. While influenza outbreaks can happen as early as October, most of the time influenza activity peaks in January or later.

In general, anyone who wants to reduce the chances of getting the flu can get vaccinated. However, certain people should get vaccinated each year either because they are at high risk of having serious flu-related complications or because they live with or care for high risk persons. During flu seasons when vaccine supplies are limited or delayed, the Advisory Committee on Immunization Practices (ACIP) makes recommendations regarding priority groups for vaccination.

People who should get vaccinated each year are:

• Children aged 6 months up to their 19th birthday

• Pregnant women

• People 50 years of age and older

• People of any age with certain chronic medical conditions

• People who live in nursing homes and other long-term care facilities

• People who live with or care for those at high risk for complications from flu, including:

• Health care workers

• Household contacts of persons at high risk for complications from the flu

• Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)

Vaccination with the nasal-spray flu vaccine is an option for healthy people 2-49 years of age who are not pregnant, even healthy persons who live with or care for those in a high risk group. The one exception is healthy persons who care for persons with severely weakened immune systems who require a protected environment; these healthy persons should get the inactivated vaccine.

Different side effects can be associated with the flu shot and nasal spray.

The flu shot: The viruses in the flu shot are killed (inactivated), so you cannot get the flu from a flu shot. Some minor side effects that could occur are

• Soreness, redness, or swelling where the shot was given

• Fever (low grade)

• Aches

If these problems occur, they begin soon after the shot and usually last 1 to 2 days. Almost all people who receive influenza vaccine have no serious problems form it. However, on rare occasions, flu vaccination can cause serious problems such as severe allergic reactions.

LAIV (FluMist®): The viruses in the nasal-spray vaccine are weakened and do not cause severe symptoms often associated with influenza illness.

In children, side effects from LAIV (FluMist®) ca include:

• Runny nose

• Wheezing

• Headache

• Vomiting

• Muscle aches

• Fever

In adults, side effects from LAIV (FluMist®) can include:

• Runny nose

• Headache

• Sore throat

• Cough

Some people should not be vaccinated without first consulting a physician. They include:

• People who have a severe allergy to chicken eggs

• People who have had a severe reaction to an influenza vaccination in the past

• People who previously developed Guillain-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine

• Children less than 6 months of age (influenza vaccine is not approved for use in this age group)

• People who have a moderate to severe illness with a fever should wait to get vaccinated until their symptoms lessen

Influenza antiviral drugs are prescription medicines (pills, liquid, or an inhaler) that fight against the flu by keeping flu viruses from reproducing in your body. Antiviral drugs can make your illness milder and make you feel better faster. They may also prevent serious flu complications. This could be especially important for people at high risk.

While getting a flu vaccine each year is the best way to protect you form the flu, antiviral drugs can be used as a second line of defense to treat the flu or to prevent flu infection. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms). When used this way, these drugs can reduce the severity of flu symptoms and shorten the time you are sick by 1 or 2 days. They also may make you less contagious to other people.

When used to prevent the flu, antiviral drugs are about 70% to 90% effective. It’s important to remember that flu antiviral drugs are not a substitute for getting a flu vaccine.

Antiviral guidance for the 2009-10 flu season is not yet released. Please refer to the 2008-09 recommendations below. CDC and the Advisory Committee on Immunization Practices (ACIP) recommend that oseltamivir (brand name Tamiflu®) or zanamavir (brand name Relenza®) should be used for the treatment and prevention of flu in the United States this season. Although amantadine and rimantadine (two other influenza antiviral drugs) also are FDA-approved for treatment and prevention of influenza, these two drugs are NOT recommended for use in the United States during the 2008-09 flu season because recent flu viruses are resistant to these drugs. When viruses are resistant to drugs, the drugs don’t work or don’t work as well.

Oseltamivir and zanamivir are both “Pregnancy Category C” medications, indicating that no studies have been conducted to assess the safety of these drugs for pregnant women. Because of the unknown effect of these drugs on pregnant women and their unborn children, these two drugs should be used during pregnancy only if the potential benefit justifies the potential risk to the unborn child. Physicians considering using one of these drugs in a pregnant woman should consult the drug package insert.

Most healthy people recover from the flu without complications. If you get the flu:

• Stay home

• Get lots of rest, drink plenty of liquids, and avoid using alcohol and tobacco

• There are over-the-counter (OTC) medications to relieve the symptoms of the flu (but never give aspirin to children or teenagers who have flu-like symptom, particularly fever)

• Remember that serious illness from the flu is more likely in certain groups of people including people 65 and older, pregnant women, people with certain chronic medical conditions and young children

• Consult your doctor early for the best treatment, but also be aware of emergency warning signs that require urgent medical attention

In children, emergency warning signs that need urgent medical attention include:

• Fast breathing or trouble breathing

• Bluish skin color

• Not drinking enough fluids

• Not waking up or not interacting

• Being so irritable that the child does not want to be held

• Flu-like symptoms improve but then return with fever and worse cough

• Fever with a rash

In adults, emergency warning signs that need urgent medical attention include:

• Difficulty breathing or shortness of breath

• Pain or pressure in the chest or abdomen

• Sudden dizziness

• Confusion

• Severe or persistent vomiting

• Cover your mouth and nose when coughing or sneezing.

• Wash your hands often using soap for at least 15-20 seconds.

• Throw away tissues after using them.

• Use alcohol-based hand sanitizers when soap and water are not available.

• Clean commonly used surfaces often (e.g., desks, handrails, doorknobs).

• Avoid close contact.

• Avoid touching your eyes, nose, or mouth.