October 20, 2006
Last reviewed and revised on January 8, 2009
By Anthony L. Komaroff, M.D.
Brigham and Women's Hospital
Public health officials and researchers are planning for the possibility of an epidemic of bird flu. Everyone hopes that such an outbreak never occurs. Meanwhile, thousands of people die of regular flu each year. We talked with Anthony L. Komaroff, M.D., about the possible threat of bird flu and what you can do to prevent ordinary flu now. Dr. Komaroff is a professor of medicine at Harvard Medical School.
What is bird flu?
Bird (avian) flu is a type of influenza virus that affects mainly birds. However, the world health community is concerned about one particular strain of bird flu virus, H5N1, that can spread to humans. From 2003 through the end of 2008, this virus has infected about 400 people worldwide. Slightly more than half have died. This means that the virus currently is very hard to pass from animals to humans, and even harder to spread from humans to other humans.
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Bird flu received so much attention in 2005. Interest seems to have faded since then. What has changed?
Very little has changed, although there is less media coverage. Doctors remain very concerned about H5N1.
At the moment, this is a good news/bad news virus. The good news is that the virus has not developed the ability to spread easily from person to person, the way most flu viruses can. The bad news is that when humans are infected with the virus, they become extremely sick.
Scientists fear that the H5N1 virus will change (mutate) in a way that makes it able to spread to and among humans. If this occurred, it could cause a worldwide epidemic (called a pandemic).
The situation is still a worldwide concern for governments and health organizations. However, now that more countries have become aware of the avian influenza virus and the possible dangers, more preparation has been put into place.
The website of the U.S. Centers for Disease Control and Prevention (CDC) offers the latest information on bird flu around the world. Most outbreaks continue to be in Asia, parts of Europe, Africa and the Near East. They are not expected to ease any time soon.
In nearly all cases, the virus has been transmitted from birds to humans. Usually, the person got sick because he or she handled an infected bird. Only a few cases involved a human catching the disease from another person.
Nevertheless, the CDC and the World Health Organization are taking the possibility of an epidemic of bird flu quite seriously.
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With flu season starting, how would you compare the current threat of regular influenza with bird flu?
Today, regular influenza caused by the influenza A and B viruses poses a much greater threat than bird flu, because it can be spread easily among people. Approximately 20,000 to 40,000 U.S. citizens — most of them older and ill from other diseases — die each year from influenza.
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Few people have close contact with birds, so what's the big worry?
There would be no significant concern if we knew that the bird flu virus would never change. Unfortunately, however, the genes of flu viruses mutate (change) easily. The H5N1 virus still could mutate into a new form that spreads easily between species and, more importantly, between humans.
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If the virus did mutate and could be transmitted from human to human, how could we control it?
Scientists are making progress in developing a safe vaccine against bird flu. The antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza) may prevent bird flu, but we can't know how effective they are until and unless there is a pandemic of bird flu. Also, if too many people take Tamiflu or Relenza indiscriminately, the virus will almost surely become resistant to the medications.
Extraordinary measures might be used to keep people from being in close contact with one another. Schools might be closed, and events and meetings involving groups of people could be canceled. Workplaces probably would get people to work from home if possible. Public transportation also would be disrupted, if not stopped altogether, during an epidemic.
The elderly and others who need assistance would get the most attention from officials. Anyone who might need extra help should plan accordingly.
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What is the best way for an individual to prevent regular flu? Will this work for bird flu?
We know a lot about preventing regular flu caused by the influenza A and B viruses. First, practice good hygiene. This will help protect you against many types of infections, including all strains of influenza. Wash your hands frequently to prevent picking up the flu and spreading infection. When you cough or sneeze, cover your mouth and nose, and move away from people who may be close to you.
Get the flu shot or the intranasal vaccine. They really work and they do not cause the flu (as some people believe). While vaccines do not give you perfect protection, your risk of getting a bad case of influenza will decrease dramatically.
When an influenza outbreak occurs in a nursing home or similar living situation, doctors sometimes will recommend that everyone who resides or works there receive antiviral medications, to protect them against getting sick.
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Should everyone get a flu shot?
It's recommended that the following individuals get vaccinated during the 2008-09 flu season:
- Children ages 6 months up to their 19th birthday
- Pregnant women
- Adults age 50 or older
- People of any age with certain chronic medical conditions:
- Heart disease
- Kidney or liver disease
- Lung disease
- Metabolic disease, such as diabetes
- Asthma
- Anemia and other blood disorders
- 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 people at high risk for complications from the flu
- Household contacts and out-of-home caregivers of children younger than 6 months of age, who are too young to be vaccinated
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What about the nasal spray instead of the flu shot?
The intranasal vaccine spray called FluMist is an alternative for healthy people between 5 and 49 years of age who are not pregnant. It appears to offer protection similar to the regular flu vaccine. The treatment is still relatively new, so it's not recommended for people who are considered at high-risk (because of age, pregnancy, a weakened immune system or certain medical conditions).
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If I get the regular flu, is there anything I can take to get better more quickly?
There are four drugs available. But the two older, less expensive generic medications (amantadine and rimantadine) don't work on all influenza types. Also, the influenza A virus is showing more and more resistance to these two drugs. The newer and more expensive drugs, oseltamivir (Tamiflu) pills and zanamivir (Relenza) mouth inhaler, are more reliable, although one of the two influenza viruses circulating in the winter of 2008-09 is resistant to oseltamivir.
To be effective, an anti-flu drug must be started within 48 hours after symptoms appear. The drugs can make symptoms less severe and may help you recover a little faster.
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Anthony L. Komaroff, M.D. is the Simcox-Clifford-Higby professor of medicine and editor-in-chief of Harvard Health Publications at Harvard Medical School. Dr. Komaroff also is senior physician and was formerly director of the Division of General Medicine at Brigham and Women's Hospital. Dr. Komaroff has served on various advisory committees to the federal government, and is an elected Fellow of the American Association for the Advancement of Science.
