Swine Flu: Questions and Answers

April 26, 2009 — -- The flu, generally, is a much more serious illness than most people appreciate. Even a "typical" flu season results in 36,000 American deaths each year, according to statistics from the U.S. Centers for Disease Control and Prevention.

The situation with swine flu is rapidly evolving, but here are some answers to questions on the top issues. Get the latest from the CDC here: http://www.cdc.gov/swineflu/

When will we have a swine flu vaccine?

To create a swine flu vaccine, the CDC together with the FDA and the NIH are working now to first make a "reference stock" of the swine flu virus. This is being done in fertilized hen cell eggs.

FDA officials have told ABC's Lisa Stark that this work began on April 24 and is taking place at a Level 3 biosafety lab at NIH. It will take a few weeks to develop this "reference stock" and the virus will then go to manufacturers to try to make a vaccine. Although the egg-based method has produced safe and effective vaccines, some analysts have said that experimental "cell-culture" based methods could cut production times.

The World Health Organization estimated that a vaccine would be available in five to six months.

John Barry, author of The Great Influenza, and distinguished visiting scholar at the Center for Bioenvironmental Research of Tulane and Xavier Universities, said that "in the best case scenario, a vaccine will be available in four months."

Should I be taking an antiviral medication such as Tamiflu or Relenza to reduce my risk for swine flu?

Infectious disease experts agree that general public should not be taking antiviral medications for protection against swine flu. The cases outside of Mexico have all been mild so far and the virus does not seem to be spreading among communities at this time. Health officials want to control use of the limited stockpiles of antiviral medications available. Broad use of the drugs also increases the odds that the swine flu virus will become resistant, and then the medications would be useless for all.

Do not take antiviral medications without consulting a physician. People who likely should be taking antiviral medications in consultation with a physician: those who are sick with the flu; those who are high risk because they have had direct contact with people who are sick; and those with compromised immune systems who are likely to have contact with the virus.

Antiviral medications such as Tamiflu and Relenza work by slowing the reproduction of the flu virus inside the body. If taken within the first 48 hours after flu symptoms start, these drugs can shorten the amount of time a person is sick by one to one-and-a-half days.

I had a flu shot this year. Will that vaccine protect me from the swine flu?

Highly unlikely. So far it appears as though the seasonal flu shot from the 2008 to 2009 flu season will not offer any protection from the swine flu virus. This is because the swine flu virus is too different from the virus strains contained within the vaccine. It is possible that health officials will decide to include the swine flu virus in next year's vaccine or design a separate swine flu vaccine. Only a vaccine that specifically included the swine flu virus would be expected to offer protection from the swine flu.

What is the difference between an epidemic and a pandemic?

An epidemic is an outbreak of disease that is limited to a discrete geographic location, while a pandemic is an epidemic that has spread to many locations – typically multiple countries.

What is the swine flu?

The swine flu is a type of influenza virus usually found in pigs. The most common version is H1N1, and the current virus causing concern is a new variation of an H1N1 virus.

Swine flu does not typically pass to humans directly, but such transmission can occur. The current swine flu virus is concerning to health experts because it has shown the ability to pass from human to human.

How big a threat is this new swine flu virus?

Scientists around the globe are working hard to determine the threat level of the current swine virus. Right now, the virus is said to have "pandemic potential" because it is a new virus that can spread from person-to-person. But if it turns out the virus does not spread easily among people, the threat level will go down. Similarly, if it turns out the virus can spread easily among people, the threat becomes more serious and the virus is more likely to trigger a pandemic.

What defines a flu pandemic?

A flu pandemic occurs when a new virus emerges that can spread easily among people. When a flu virus mutates in such a way that it forms a novel version, it means people typically have little-to-no protection because their immune systems have no experience fighting the virus in the past. Flu viruses can spread quickly and potentially cause more severe illness when the population lacks immunity.

But all pandemics are not equally deadly. Some kill millions more people than usual, while others are roughly on par with seasonal flu in terms of deaths.

It is not possible to predict a pandemic in advance so health officials keep a close watch on viruses that have "pandemic potential" -- new viruses that have shown at least some ability to transmit to humans. The current H5N1 bird flu circulating in Asia is an example of a virus that has pandemic potential, but has not yet caused a pandemic.

What does a pandemic mean in terms of the death rate? Would it necessarily be severe?

Pandemics can vary quite a bit in severity. The 1918 pandemic killed many more Americans than an ordinary flu, while the 1968 version killed about 34,000 people -- about the same number killed each year by seasonal flu, according to CDC statistics.

The world generally experiences at least two flu pandemics each century. Historically, the 20th century saw 3 pandemics of influenza:

The 1918 influenza pandemic caused at least 675,000 U.S. deaths and up to 50 million deaths worldwide.

The 1957 influenza pandemic caused at least 70,000 U.S. deaths and 1-2 million deaths worldwide.

The 1968 influenza pandemic caused about 34,000 U.S. deaths and 700,000 deaths worldwide.

How does the swine flu spread?

Researchers are still investigating how easily the swine flu virus spreads, but experts say that transmission likely occurs the same way people pass on the usual flu: coughing or sneezing from sick people, shaking hands or otherwise touching persons who are infected with the virus, touching surfaces and objects that sick people have touched.

Can I get the swine flu from eating pork?

No, there are no signs that people can get the swine flu from eating pork.

How can I protect myself?

The CDC recommends the following steps to protect yourself from flu:

Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.

Avoid touching your eyes, nose or mouth. Germs spread that way.

Try to avoid close contact with sick people.

Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people.

If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.

What are the symptoms of swine flu? How do I know if I have it?

The World Health Organization is working to develop a profile of the "typical case" of swine flu, but thus far, the symptoms appear to be essentially the same as those for the usual winter flu. Hallmark symptoms of flu include high fever, muscle aches, headache, and fatigue. People may also experience coughing and a runny nose, or less commonly, vomiting and diarrhea.

The only way to definitively diagnose swine flu is to have laboratory testing done to determine the exact subtype of the virus.

Can the swine flu be treated? What if I develop symptoms?

Yes, the swine flu can be treated with antiviral medications such as Tamiflu and Relenza, but treatment must be started within the first 48 hours after symptoms appear. If you have symptoms of flu, talk to your health care provider right away.

Sources: the CDC, the World Health Organization, and the National Institute of Allergy and Infectious Diseases