Anthrax Q & A: Anthrax and Influenza
(flu) and inhalation anthrax can have similar symptoms. Does CDC recommend
that I get a flu shot to help diagnose anthrax?
You should get a flu shot only to prevent the flu. CDC does not recommend you get the flu shot so doctors can tell whether you have the flu or anthrax. Many illnesses (including anthrax) begin with flu-like symptoms, which include fever, body aches, tiredness, and headaches. In fact, most illnesses with flu-like symptoms are not either the flu or anthrax.
The flu vaccine is the best protection you can get to prevent the flu and its severe complications, especially among those who are at the highest risk (e.g., people older than 65 years old or younger people with chronic disease such as diabetes or heart disease). The flu shot can prevent 70%-90% of flu infections, but it will not prevent illnesses with flu-like symptoms caused by anything other than influenza.
a way to distinguish between early inhalation anthrax and flu?
Early inhalation anthrax symptoms can be similar to those of much more common infections. However, a runny nose is a rare feature of anthrax. This means that a person who has a runny nose along with other common influenza-like symptoms is by far more likely to have the common cold than to have anthrax.
In addition, most people with inhalation anthrax have high white blood cell counts and no increase in the number of lymphocytes. On the other hand, people with infections such as flu usually have low white blood cell counts and an increase in the number of lymphocytes.
Chest X-rays are also critical diagnostic tools. Chest X-rays showed that all patients with inhalation anthrax have some abnormality, although for some patients, the abnormality was subtle. CT scans can confirm these abnormalities.
a quick test that doctors can do to tell whether I have anthrax or an
illness like the flu?
Some influenza detection tests give results fairly quickly. However, these tests are not perfect and are not appropriate for every patient. Rapid influenza tests can provide results within 24 hours; viral culture provides results in 3-10 days. However, as many as 30% of samples that test positive for influenza by viral culture may give a negative rapid test result. And, some rapid test results may indicate influenza when a person is not infected with influenza.
For more information on testing for flu, go to www.cdc.gov/ncidod/diseases/flu/flu_dx_table.htm.
- Page last updated May 2, 2003
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