The 2009 H1N1 virus (previously known as “swine flu”) is a respiratory disease that is caused by type A (H1N1) influenza viruses that originally were traced to pigs and then mutated into a strain that is a combination of pig, avian and human strains of influenza viruses. 

Like seasonal flu virus strains, the 2009 H1N1 virus can vary in severity from mild to severe. From 2005 until January 2009, the US documented 12 human cases of this flu, but it has rarely resulted in death. However, infection with this particular virus can present serious health risks. In September 1988, a previously healthy 32-year-old pregnant woman who became infected with the H1N1 virus was hospitalized for pneumonia and died eight days later. A 1976 outbreak in Fort Dix, NJ resulted in more than 200 reported cases of serious illness and one death.

Both the Center for Disease Control (US focus) and the World Health Organizations (global) sites are excellent sources for the most current information on the virus.

 CDC H1N1 flu site  

 WHO H1N1 flu highlights 

Who may be at risk

• Individuals who are at high risk for developing complications from influenza (persons with certain chronic medical conditions, the elderly)
• Household close contacts of a person who has been confirmed or is suspected of having influenza, or is in close contact with someone who is at high risk of developing complications from influenza
• School children who are at high risk for developing complications from influenza (persons with certain chronic medical conditions) and/or who have had close contact (face to face) with an individual confirmed or suspected to have influenza
• Travelers to Mexico who are at high risk for developing complications from influenza (persons with certain chronic medical conditions, the elderly)
• Border workers (US/Mexico) who are at high risk for developing complications from influenza (persons with certain chronic medical conditions, the elderly)
• Health care workers or public health workers who have had unprotected close contact with an individual who had a confirmed case of H1N1 virus infection during the individual’s infectious period
   

Antiviral chemoprophylaxis can be considered for the following:

• Any health care worker who is at high risk for developing complications from influenza (persons with certain chronic medical conditions, the elderly) who is working in an area with confirmed H1N1 virus infection cases and who is caring for patients with any acute febrile respiratory illness
• Non-high-risk persons who are travellers to Mexico, first responders, or border workers who are working in areas with confirmed cases of H1N1 virus infection.

Before traveling:

 CDC traveler's health site

Neither the WHO nor the CDC has issued travel restrictions to Mexico. The WHO is not restricting regular travel or closure of borders. There are, however, prudent courses of action:

• People who are ill should delay international travel.
• And people who develop symptoms following international travel should seek medical attention, in line with guidance from national authorities.

  WHO H1N1 update

• US travelers who are at high risk of severe illness from influenza (for example, the elderly and persons with chronic conditions such as diabetes, lung disease or heart disease) should take antiviral medications for prevention of this virus strain if they are traveling to Mexico.
• The European Union has issued a recommendation against unnecessary travel to Mexico and the United States.
• Hong Kong called for residents to avoid all travel to Mexico and to try to avoid travel to cities with confirmed cases in the United States.

Recommended antiviral drugs for swine influenza are oseltamivir (brand name Tamiflu®) and zanamivir (brand name Relenza®). Both are prescription drugs that help fight against the H1N1 virus by keeping flu viruses from reproducing in your body. These drugs can help prevent infection if taken as a prophylaxis. Talk to your doctor about correct indications for using influenza antiviral medications. Always seek medical care if you are severely ill.

 CDC traveler's health site

Practical advice: What you need to know about 2009 H1N1 virus

What are the signs and symptoms of the 2009 H1N1 virus (“swine flu”) in people?

The 2009 H1N1 virus symptoms are similar to the symptoms of more typical strains of human flu and include fever, cough, sore throat, body aches, headache, chills and fatigue. Some people have also reported diarrhea and vomiting. In the past, severe illness (pneumonia and respiratory failure) and deaths have been reported with H1N1 virus infections. As seen with seasonal flu, H1N1 virus may cause a worsening of underlying chronic medical conditions.

How does H1N1 virus spread?

Spread of this H1N1 virus is thought to be happening in the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person when droplets from a cough or sneeze of an infected person move through the air. Sometimes people may become infected by touching something that has flu viruses on it and then touching their eyes, mouth or nose. Germs can be spread when a person touches respiratory droplets from another person on a surface like a desk and then touches his or her own eyes, mouth or nose before washing his or her hands.

How long can an infected person spread H1N1 virus to others?

Infected people may be able to pass the virus to others beginning one day before symptoms develop and up to seven or more 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. People with H1N1 virus infection should be considered potentially contagious as long as they are symptomatic and possibly for up to seven days following illness onset. Children, especially younger children, might potentially be contagious for longer periods.

How long can viruses live outside the body?

We know that some viruses and bacteria can live two hours or longer on surfaces such as cafeteria tables, doorknobs and desks. Frequent hand washing will help you reduce the chance of getting contaminated with the H1N1 virus from these common surfaces.

Are any medicines available to treat H1N1 virus?

Yes. The US Centers for Disease Control and Prevention (CDC) recommends the use of oseltamivir (brand name Tamiflu®) or zanamivir (brand name Relenza®) for the treatment and/or prevention of infection with the H1N1 virus. Antiviral drugs are prescription medicines (pills, liquid or an inhaler) that fight against the flu by keeping flu viruses from reproducing in your body. If you get sick, antiviral drugs can help make your illness milder and help you feel better faster. They also may help prevent serious flu complications. For treatment, antiviral drugs work best if taken soon after getting sick (within two days of the onset of symptoms).

How can I help protect myself and others from getting sick?

While a specific vaccine is now available (still focused on those more at risks), certain everyday actions can help prevent the spread of germs. Take these everyday steps to protect your health:

• Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue into the trash after you use it.
• Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective.
• Avoid touching your eyes, nose and mouth whenever possible, and especially after you have been around infected individuals. Germs spread this way.
• Try to avoid close contact with people who are sick, and also try not to touch surfaces that may be contaminated with the flu virus.
• If you get sick or even develop symptoms of influenza, the CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.
• Get plenty of rest, be physically active, manage your stress, drink plenty of fluids and eat nutritious food.

What is the best technique for washing my hands to avoid getting the flu?

Washing your hands often will help protect you from becoming infected by germs. Wash with soap and water, or clean your hands with an alcohol-based hand cleaner. The CDC recommends that you wash your hands with soap and warm water for at least 15 to 20 seconds. When soap and water are not available, alcohol-based disposable hand wipes or gel sanitizers may be used. You can find them in most supermarkets and drugstores. If using gel, rub your hands until the gel is dry. The gel doesn't need water to work; the alcohol in it kills the germs on your hands.

What should I do if I get sick?

If you live in areas where H1N1 virus cases have been identified and become ill with influenza-like symptoms – including fever, body aches, runny nose, sore throat, nausea, or vomiting or diarrhea – you may want to contact your health care provider, particularly if you are worried about your symptoms. A health care professional can determine whether influenza testing or treatment is needed.

If you are sick, you should stay home and avoid contact with other people as much as possible to keep from spreading your illness to others.

If you become ill and experience any of the following warning signs, seek emergency medical care.

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 that 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

Download PDF of Practical Advice

 US print version   A4 print version

H1N1 Self-Assessment Resource

Emory University provided the content to populate this site and there is no licensing fee to access.  It contains survey questions and information on what to do if you have flu-like illness and is being offered to the public at no cost.