FAQs About H1N1 Flu

Below you will find questions and answers about the 2009 novel H1N1 virus and vaccine from Sharp HealthCare and from the Centers for Disease Control and Prevention (CDC). For the latest information from the county, CDC and other agencies, please visit the County of San Diego's flu website.

What is H1N1?
Novel H1N1 (referred to as "swine flu" early on) was first detected in the United States in April 2009 as a new influenza virus causing illness in people. The virus spreads from person-to-person, in much the same way that regular seasonal influenza viruses spread.

Why is H1N1 sometimes called “swine flu”?
This virus was originally referred to as “swine flu” because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs (swine) in North America. But further study has shown that this new virus is very different from what normally circulates in North American pigs.

How serious is H1N1 flu? How is it spread?
Like seasonal flu, H1N1 flu in humans can vary in severity from mild to severe.

Spread of H1N1 virus occurs in much the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person through coughing or sneezing by people with influenza. Sometimes people may become infected by touching something — such as a surface or object — with flu viruses on it and then touching their mouth or nose. H1N1 influenza spreads person-to-person through coughing or sneezing of infected people.

What are the signs and symptoms of this virus?
People with H1N1 flu virus often exhibit the following symptoms:

  • Body aches
  • Chills
  • Cough
  • Fatigue
  • Fever 
  • Headache 
  • Runny or stuffy nose 
  • Sore throat   

A significant number of people infected with this virus also reported diarrhea and vomiting. Severe illnesses and death have occurred as a result of illness associated with this virus.

How severe is illness associated with H1N1 flu virus?
Illness with H1N1 virus has ranged from mild to severe. While most people who have been sick have recovered without needing medical treatment, hospitalizations and deaths from infection with this virus have occurred.

What groups are most affected by the H1N1 flu virus?
Six months to 60 years of age is the age group most affected. About 70 percent of people who have been hospitalized with H1N1 virus have had one or more medical conditions previously recognized as placing people at “high risk” of serious seasonal flu-related complications. This includes pregnancy, diabetes, heart disease, asthma and kidney disease.

When the novel H1N1 outbreak was first detected in mid-April 2009, CDC began working with states to collect, compile and analyze information regarding the novel H1N1 flu outbreak, including the numbers of confirmed and probable cases and the ages of these people. The information analyzed by CDC supports the conclusion that the new H1N1 flu has caused greater disease burden in people younger than 25 years of age than in older people.

How does H1N1 flu compare to seasonal flu in terms of its severity and infection rates?
Seasonal influenza and H1N1 can cause mild to severe illness, and at times can lead to death. Each year, in the United States, on average 36,000 people die from seasonal flu-related complications and more than 200,000 people are hospitalized from flu-related causes. In the 2009-2010 flu season, less than 1,000 deaths were associated with H1N1. For the latest statistics, please visit the CDC’s website.

How long can an infected person spread this virus to others?
People infected with seasonal and H1N1 flu may be able to infect others from one day before getting sick to five to seven days after. This can be longer in some people, especially children and people with weakened immune systems and in people infected with H1N1.

What can I do to protect myself from getting sick?
As always, a vaccine will be available to protect against seasonal influenza.

Take these everyday actions to help prevent the spread of germs that cause respiratory illnesses like influenza:

  • Avoid touching your eyes, nose or mouth. Germs spread this way. 
  • Cover your nose and mouth with a tissue when you cough or sneeze or cough into your sleeve. Throw the tissue in the trash after you use it and immediately wash your hands afterwards.
  • If you are sick with flu-like illness, CDC recommends that you stay home for at least 24 hours after your fever is gone except to get medical care or for other necessities. (Your fever should be gone without the use of a fever-reducing medicine.) Keep away from others as much as possible to keep from making others sick. If you work in a clinical setting, you must stay home 7 days from onset of symptoms or for 24 hours after your fever (without the use of fever-reducing medicine) has subsided, whichever is greatest.
  • Try to avoid close contact with sick people. 
  • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective. 

Other important actions that you can take are:

  • Be prepared in case you get sick and need to stay home for a week or so. A supply of over-the-counter medicines, alcohol-based hand rubs, tissues and other related items could be useful and help avoid the need to make trips out in public while you are sick and contagious.
  • Follow public health advice regarding school closures, avoiding crowds and other social distancing measures.

What is the best technique for washing my hands to avoid getting the flu?
Washing your hands often will help protect you from germs. Wash with soap and water or clean with alcohol-based hand cleaner. CDC recommends that you wash your hands with soap and warm water for 15 to 20 seconds.

What should I do if I get sick?
CDC recommends that you stay home for at least 24 hours after your fever is gone except if you need to get medical care or for other necessities. (Your fever should be gone without the use of a fever-reducing medicine.) If you work in a clinical setting, you must stay home 7 days from onset of symptoms or for 24 hours after your fever (without the use of fever-reducing medicine) has subsided, whichever is greatest.

Stay away from others as much as possible to keep from making others sick. Staying at home means that you should not leave your home except to seek medical care.

If you have severe illness or you are at high risk for flu complications, contact your health care provider or seek medical care. Your health care provider will determine whether flu testing or treatment is needed.

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:

  • Being so irritable that the child does not want to be held
  • Bluish or gray skin color
  • Fast breathing or trouble breathing
  • Flu-like symptoms improve but then return with fever and worse cough
  • Not drinking enough fluids
  • Not waking up or not interacting
  • Severe or persistent vomiting

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

  • Confusion
  • Difficulty breathing or shortness of breath
  • Flu-like symptoms improve but then return with fever and worse cough
  • Pain or pressure in the chest or abdomen
  • Sudden dizziness  
  • Severe or persistent vomiting

Are there medicines to treat H1N1?
Yes. Antivirals are sometimes used to treat influenza. If you have underlying medical conditions or are in a high-risk group, consult with your physician to determine if antivirals would be recommended.

How long can influenza virus remain viable on objects (such as books and doorknobs)?
Studies have shown that influenza virus can survive on environmental surfaces and can infect a person for two to eight hours after being deposited on the surface.

What kills influenza?
Influenza virus is destroyed by heat (167 to 212 degrees Fahrenheit [75 to 100 degrees Celsius]). In addition, several chemical germicides, including chlorine, hydrogen peroxide, detergents (soap), iodophors (iodine-based antiseptics) and alcohols are effective against human influenza viruses if used in proper concentration for a sufficient length of time. For example, wipes or gels with alcohol in them can be used to clean hands. The gels should be rubbed into hands until they are dry.

What surfaces are most likely to be sources of contamination?
Germs can be spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose or mouth. Droplets from a cough or sneeze of an infected person move through the air. Germs can be spread when a person touches respiratory droplets from another person on a surface like a desk, for example, and then touches his or her eyes, mouth or nose before washing his or her hands.

What can I do to prevent spread of the influenza within my home?
To prevent the spread of influenza virus, it is recommended that tissues and other disposable items used by an infected person be thrown in the trash. Additionally, persons should wash their hands with soap and water after touching used tissues and similar waste.

To prevent the spread of influenza virus it is important to keep surfaces (especially bedside tables, surfaces in the bathroom, kitchen counters and toys for children) clean by wiping them down with a household disinfectant according to directions on the product label.

Linens, eating utensils and dishes belonging to those who are sick do not need to be cleaned separately, but importantly these items should not be shared without washing thoroughly first. Linens (such as bed sheets and towels) should be washed by using household laundry soap and tumbled dry on a hot setting. Individuals should avoid “hugging” laundry prior to washing it to prevent contaminating themselves. Individuals should wash their hands with soap and water or alcohol-based hand rub immediately after handling dirty laundry. Eating utensils should be washed either in a dishwasher or by hand with water and soap.

For More Information
To learn more about Sharp's services or to find a Sharp-affiliated physician, search for San Diego doctors or call 1-800-82-SHARP (1-800-827-4277), Monday through Friday, 8 am to 6 pm. To find general information about flu care health, visit Influenza in Adult Health or read the Infectious Diseases News archive.