WebMD Provides Answers to Your Questions About Swine Flu
By Daniel J. DeNoon
WebMD Health News
Reviewed By Louise Chang, MD
The swine flu virus in the U.S. is the same one causing a deadly epidemic in Mexico. What is swine flu? What can we do about it?
- What is swine flu?
- What are swine flu symptoms?
- Who is at highest risk of H1N1 swine flu?
- If I think I have swine flu, what should I do?
- How does swine flu spread?
- How is swine flu treated?
- Is there a vaccine against the new swine flu virus?
- I had a flu vaccine this season. Am I protected against swine flu?
- How can I prevent swine flu infection?
- Should I wear a face mask or respirator?
- How long does the flu virus survive on surfaces?
- Can I still eat pork?
- What else should I be doing?
- How severe is swine flu?
- Why has the swine flu infection been deadlier in Mexico than in other countries?
- Have there been previous swine flu outbreaks?
- I was vaccinated against the 1976 swine flu virus. Am I still protected?
- How many people have swine flu?
- How serious is the public health threat of a swine flu epidemic?
The Latest on
H1N1 Swine Flu
Learn about H1N1 swine flu:
- Swine Flu Symptoms
- Swine Flu FAQ
- Swine Flu Pictures
- Complete Swine Flu Coverage on WebMD
What is swine flu?
Like people, pigs can get influenza (flu), but swine flu viruses aren't the same as human flu viruses. Swine flu doesn't often infect people, and the rare human cases that have occurred in the past have mainly affected people who had direct contact with pigs. But the current "swine flu" outbreak is different. It's caused by a new swine flu virus that has changed in ways that allow it to spread from person to person -- and it's happening among people who haven't had any contact with pigs. That makes it a human flu virus. In an effort to avoid confusion, the CDC is calling the virus "novel influenza A (H1N1) virus" to distinguish it both from flu viruses that infect mainly pigs and from the seasonal influenza A H1N1 viruses that have been in circulation for many years.
What are swine flu symptoms?
Symptoms of swine flu are like regular flu symptoms and include fever, cough, sore throat, runny nose, body aches, headache, chills, and fatigue. Many people with swine flu have had diarrhea and vomiting. Nearly everyone with flu has at least two of these symptoms. But these symptoms can also be caused by many other conditions. That means that you and your doctor can't know, just based on your symptoms, if you've got swine flu. Health care professionals may offer a rapid flu test, although a negative result doesn't necessarily mean you don't have the flu.
Only lab tests can definitively show whether you've got swine flu. State health departments can do these tests. But given the large volume of samples coming in to state labs, these tests are being reserved for patients with severe flu symptoms. Currently, doctors are reserving antiviral drugs for people with or at risk of severe influenza.
Who is at highest risk of H1N1 swine flu?
Most U.S. cases of H1N1 swine flu have been in older children and young adults. It's not clear why, and it's not clear whether this will change.
But certain groups are at particularly high risk of severe disease or bad outcomes if they get the flu:
- Pregnant women
- Young children, especially those under 12 months of age
- Elderly people are at high risk of severe flu disease. But relatively few swine flu cases have been seen in people over age 65.
- People with heart disease or risk factors for heart disease
- People with HIV infection
- People with chronic diseases
- People taking immune-suppressing drugs, such as cancer chemotherapy or anti-rejection drugs for transplants
People in these groups should seek medical care as soon as they get flu symptoms.
If I think I have swine flu, what should I do? When should I see my doctor?
If you have flu symptoms, stay home, and when you cough or sneeze, cover your mouth and nose with a tissue. Afterward, throw the tissue in the trash and wash your hands. That will help prevent your flu from spreading.
If you have only mild flu symptoms, you do not need medical attention unless your illness gets worse. But if you are in one of the groups at high risk of severe disease, contact your doctor at the first sign of flu-like illness. In such cases, the CDC recommends that people call or email their doctor before rushing to an emergency room.
But there are emergency warning signs.
Children should be given urgent medical attention if they:
- Have fast breathing or trouble breathing
- Have bluish or gray skin color
- Are not drinking enough fluid
- Are not waking up or not interacting
- Have severe or persistent vomiting
- Are so irritable that the child does not want to be held
- Have flu-like symptoms that improve but then return with fever and a worse cough
- Have fever with a rash
Adults should seek urgent medical attention if they have:
- Difficulty breathing or shortness of breath
- Pain or pressure in the chest or abdomen
- Sudden dizziness
- Severe or persistent vomiting
- Flu-like symptoms that improve, but then come back with worsening fever or cough
Keep in mind that your doctor will not be able to determine whether you have swine flu, but he or she may take a sample from you and send it to a state health department lab for testing to see if it's swine flu. If your doctor suspects swine flu, he or she would be able to write you a prescription for Tamiflu or Relenza. These antiviral medications aren't a question of life or death for the vast majority of people. Most U.S. swine flu patients have made a full recovery without antiviral drugs.
How does swine flu spread? Is it airborne?
The new swine flu virus apparently spreads just like regular flu. You could pick up germs directly from droplets from the cough or sneeze of an infected person, or by touching an object they recently touched, and then touching your eyes, mouth, or nose, delivering their germs for your own infection. That's why you should make washing your hands a habit, even when you're not ill. Infected people can start spreading flu germs up to a day before symptoms start, and for up to seven days after getting sick, according to the CDC.
The swine flu virus can become airborne if you cough or sneeze without covering your nose and mouth, sending germs into the air.
The U.S. residents infected with swine flu virus had no direct contact with pigs. The only way to get the new swine flu is from another person.
How is swine flu treated?
The new swine flu virus is sensitive to the antiviral drugs Tamiflu and Relenza. The CDC recommends those drugs to prevent or treat swine flu; the drugs are most effective when taken within 48 hours of the start of flu symptoms. But not everyone needs those drugs. Most people who have come down with swine flu have recovered without treatment. The Department of Homeland Security has released 25% of its stockpile of Tamiflu and Relenza to states. Health officials have asked people not to hoard Tamiflu or Relenza.
Is there a vaccine against the new swine flu virus?
No. But the CDC and the World Health Organization are already taking the first steps toward making such a vaccine. That's a lengthy process that takes months. The process includes limited clinical tests to see how well the vaccine elicits flu-neutralizing antibodies and to evaluate vaccine safety. If everything goes perfectly -- and flu vaccine production is very tricky -- there could be a U.S. swine flu vaccine in October 2009. But that is an extremely optimistic prediction.
Even if officials decide to make a swine flu vaccine for this winter, many questions remain. It's not yet clear whether people will need one or two shots or whether an immune-boosting substance called adjuvant will have to be used. And, it's still not clear who should be vaccinated first, and who should be at the end of the line.
I had a flu vaccine this season. Am I protected against swine flu?
No. This season's flu vaccine does not protect against the new swine flu virus.
Whether or not there's a swine flu vaccine this winter, there will be a new seasonal flu vaccine in the fall. This year, it will be more important than ever to get a flu shot. It may not protect against swine flu -- but it will keep you and others from getting the seasonal flu viruses that kill some 36,000 Americans each year.
How can I prevent swine flu infection?
The CDC recommends taking these steps:
- Wash your hands regularly with soap and water, especially after coughing or sneezing. Or, use an alcohol-based hand cleaner if soap and water are not available.
- Avoid close contact -- that is, being within six feet -- with people who have flu-like symptoms.
- Avoid touching your mouth, nose, or eyes. That's not easy to do, so keep those hands clean.
- If you have flu-like symptoms -- fever plus at least cough or sore throat or other flu symptoms -- stay home for seven days after symptoms begin or until you've been symptom-free for 24 hours -- whichever is longer.
- The CDC does not recommend using a face mask or respirator in community or home settings. However, the CDC says that people at increased risk of severe flu illness may consider wearing a N-95 respirator or face mask in crowded settings in communities where swine flu is circulating or when taking care of a person with flu-like illness. It's not known whether face masks actually protect against flu transmission.
- People who have or are suspected of having swine flu should wear a face mask, if available and tolerable, when sharing common spaces with other household members, when outside the home, or when breastfeeding.
Should I wear a face mask or respirator?
Every day, newspapers carry pictures of people wearing face masks to prevent swine flu transmission. But very little is known about whether face masks actually protect against the flu.
There's a difference between a face mask and a respirator. A face mask does not seal tightly to the face. Face masks include masks labeled as surgical, dental, medical procedure, isolation, or laser masks. Respirators are N95 or higher filtering face pieces that fit snugly on the face. Respirators, when correctly adjusted, filter out virus particles -- but it's hard to breathe through them for extended periods, and they cannot be worn by children or people with facial hair.
People who have flu-like symptoms should carry disposable tissues to cover their coughs and sneezes. When going out in public, or when sharing common spaces around the home with family members, they should put on a face mask -- if one is available and tolerable.
People not at risk of severe flu illness can best protect themselves from swine flu with frequent handwashing and by staying at least six feet away from people with flu symptoms. But if swine flu is circulating in the community, a face mask or respirator may be protective in crowded public places.
People at increased risk of severe flu illness -- pregnant women, for example -- may wish to consider using a facemask under certain circumstances, such as when providing assistance to a person with flu-like illness. But the CDC prefers such people follow more tried-and-true methods of staying healthy, such as handwashing and avoiding ill people.
How long does the flu virus survive on surfaces?
Flu bugs can survive for hours on surfaces. One study showed that flu viruses can live for up to 48 hours on hard, nonporous surfaces such as stainless steel and for up to 12 hours on cloth and tissues. The virus seems to survive for only minutes on your hands -- but that's plenty of time for you to transfer it to your mouth, nose, or eyes.
Can I still eat pork?
Yes. You can't get swine flu by eating pork, bacon, or other foods that come from pigs.
What else should I be doing?
Keep informed of what's going on in your community. Your state and local health departments may have important information if swine flu develops in your area. For instance, parents might want to consider what they would do if their child's school temporarily closed because of flu. Don't panic, but a little planning wouldn't hurt.
Here's the advice from the U.S. government's pandemicflu.gov web site:
To plan for a pandemic:
- Store a two-week supply of water and food. During a pandemic, if you cannot get to a store, or if stores are out of supplies, it will be important for you to have extra supplies on hand. This can be useful in other types of emergencies, such as power outages and disasters.
- Periodically check your regular prescription drugs to ensure a continuous supply in your home.
- Have any nonprescription drugs and other health supplies on hand, including pain relievers, stomach remedies, cough and cold medicines, fluids with electrolytes, and vitamins.
- Talk with family members and loved ones about how they would be cared for if they got sick, or what will be needed to care for them in your home.
- Volunteer with local groups to prepare and assist with emergency response.
- Get involved in your community as it works to prepare for an influenza pandemic.
Items to have on hand for an extended stay at home:
Examples of food and non-perishables
Examples of medical, health, and emergency supplies
• Ready-to-eat canned meats, fish, fruits, vegetables, beans, and soups
• Prescribed medical supplies such as glucose and blood-pressure monitoring equipment
• Protein or fruit bars
• Soap and water, or alcohol-based (60-95%) hand wash
• Dry cereal or granola
• Medicines for fever, such as acetaminophen or ibuprofen
• Peanut butter or nuts
• Dried fruit
• Anti-diarrheal medication
• Canned juices
• Fluids with electrolytes
• Bottled water
• Cleansing agent/soap
• Canned or jarred baby food and formula
• Pet food
• Other non-perishable items
• Portable radio
• Manual can opener
• Garbage bags
• Tissues, toilet paper, disposable diapers
How severe is swine flu?
The severity of cases in the current swine flu outbreak has varied widely, from mild cases to fatalities. Most U.S. cases have been mild, but there have been a number of deaths and hundreds of hospitalizations -- mostly in young people aged 5 to 24 years.
It's impossible to know whether the virus will go away or whether it will become more deadly. Scientists are watching closely to see which way the new swine flu virus is heading -- but health experts warn that flu viruses are notoriously hard to predict.
But there's a lot of planning you can do. CDC officials predict that just about every U.S. community will have H1N1 swine flu cases. It's possible some schools in your community may temporarily close. So make contingency plans just in case you are affected. For more information on preparedness planning, see the U.S. government's pandemicflu.gov web site.
Why has the swine flu infection been deadlier in Mexico than in other countries?
That's not clear yet. Researchers around the world are investigating the differences between the cases in Mexico and those elsewhere. The data so far suggests that many more people in Mexico had mild swine flu infections than had originally been appreciated.
Have there been previous swine flu oubtreaks?
Yes. There was a swine flu outbreak at Fort Dix, N.J., in 1976 among military recruits. It lasted about a month and then went away as mysteriously as it appeared. As many as 240 people were infected; one died.
The swine flu that spread at Fort Dix was the H1N1 strain. That's the same flu strain that caused the disastrous flu pandemic of 1918-1919, resulting in tens of millions of deaths worldwide.
Concern that a new H1N1 pandemic might return in winter 1976 led to a crash program to create a vaccine and vaccinate all Americans against swine flu. That vaccine program ran into all kinds of problems -- not the least of which was public perception that the vaccine caused excessive rates of dangerous reactions. That may not have been the case. But after more than 40 million people were vaccinated, the effort was abandoned.
As it turned out, there was no swine flu epidemic.
Even though it's an H1N1 type A flu bug, the new swine flu is a different virus than the ones that emerged in 1918 and in 1976 -- and from the seasonal type A H1N1 virus that has been circulating for many years.
There have been two flu pandemics since 1918 -- one that began in 1957, and another that began in 1968.
I was vaccinated against the 1976 swine flu virus. Am I still protected?
Probably not. The new swine flu virus is different from the 1976 virus. And it's not clear whether a vaccine given more than 30 years ago would still be effective.
How many people have swine flu?
That's a hard question to answer because the figure is changing so quickly. If you want to keep track of U.S. cases that have been confirmed by lab tests and reported to the CDC, check the CDC's web site. If you're looking for cases in other countries, visit the World Health Organization's web site. And, when you hear about large numbers of people who are ill, remember that lab tests may not yet have been done to confirm that they have swine flu. And, there may be a little lag time before confirmed cases make it into the official tally.
But these numbers are misleading, because mild flu cases are rarely counted. Flu experts estimate that for every confirmed case of flu, there are 20 additional flu infections.
How serious is the public health threat of a swine flu epidemic?
The U.S. government has declared swine flu to be a public health emergency.
It remains to be seen how severe swine flu will be in the U.S. and elsewhere, but countries worldwide are monitoring the situation closely and preparing for the possibility of a pandemic.
The World Health Organization has declared swine flu to be a pandemic. That means that all nations can expect to see swine flu infections -- and should prepare for them -- but does not mean the virus has become more severe.
The H1N1 swine flu outbreak comes at the end of the U.S. flu season. The virus has spread across the nation. Nobody knows whether it will stick around all summer or whether it will get worse when flu season begins again this fall. But the CDC is warning Americans to prepare for a bad flu season this fall. It's better to over prepare and look a little silly if nothing happens than to be unprepared for an emergency.
Scientists are closely watching the Southern Hemisphere to see whether the H1N1 swine flu begins to circulate there. If it does, it will be important to see whether the virus changes over time, and whether it spreads more efficiently in the winter months.
WebMD senior writer Miranda Hitti contributed to this report.
SOURCES: CDC. World Health Organization. Pandemicflu.gov
©2009 WebMD, LLC. All Rights Reserved.