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November 15, 2003
Questions and Answers on Hepatitis A Outbreaks
Associated with Eating Raw or Undercooked Green Onions (Scallions)
What did FDA announce today?
FDA advised consumers that three recent hepatitis A outbreaks have been
associated with eating raw or undercooked green onions (scallions).
Does this announcement apply to all products containing green onions?
No. It only applies to raw or undercooked green onions or products
containing them. Commercially prepared products, such as salsa in jars,
have received a treatment that eliminates the hepatitis A virus.
- What can consumers do to decrease their risk of infection from
hepatitis A caused by contaminated green onions?
Consumers can cook all raw green onions thoroughly before eating them.
This minimizes the risk of illness by reducing or eliminating the virus.
Consumers can also avoid eating raw or lightly cooked green onions.
Consumers who wish to avoid undercooked green onions should also
specifically request that raw or lightly cooked green onions not be added
to their food prepared in restaurants.
- Should additional precautions be taken by people with chronic liver
disease or weakened immune systems such as patients undergoing
chemotherapy or AIDS patients?
Persons with chronic liver disease or weakened immune systems are not more
likely to acquire hepatitis A. However, persons with these chronic
illnesses sometimes have a more severe form of hepatitis A. People with
chronic liver disease or weakened immune systems should consider avoiding
raw or undercooked green onions until the cause of green onion
contamination has been identified and corrected. All persons with chronic
liver disease should get hepatitis A vaccination (see below).
- What caused the outbreak of hepatitis A in the Pittsburgh area?
The State of Pennsylvania, the Centers for Disease Control and Prevention
(CDC) and FDA are working together to investigate this outbreak. As of
November 15, 2003, the investigation is not finished, and it is not yet
known what caused this outbreak. Investigators are now trying to determine
if the outbreak was caused by a contaminated food such as raw or
undercooked green onions.
- Has FDA asked the restaurant industry to do anything in response to
Yes. FDA has informed the restaurant industry of the association of
hepatitis A with raw or undercooked green onions in recent outbreaks so
that restaurants can take actions to protect their customers.
- What are the symptoms of hepatitis A?
The average incubation period for hepatitis A is 28 days (range: 15-50
days). This means that symptoms of hepatitis A develop within 50 days of
exposure. Persons with hepatitis A virus infection may not have any signs
or symptoms of the disease. Adults are more likely to have symptoms than
children. If symptoms are present, they usually occur abruptly and may
include fever, tiredness, loss of appetite, nausea, abdominal discomfort,
dark urine, and jaundice (yellowing of the skin and eyes). Symptoms
usually last less than 2 months; a few persons are ill for as long as 6
months. There is no chronic infection with the hepatitis A virus.
- How serious is hepatitis A?
Most persons with hepatitis A make a full recovery and will never get
hepatitis A again. However, in rare instances (an average of 3 in every
1000 reported cases), hepatitis A can be fatal.
- What should consumers do if they recently ate food containing raw or
lightly cooked green onions?
Consumers who have recently eaten raw or lightly cooked green onions and
feel well only need to monitor their health. Consumers who are
experiencing symptoms that might be hepatitis A should consult their
health care provider.
- Is there a test for hepatitis A?
Yes, there is a blood test for hepatitis A, called an IgM anti-HAV.
However, the only people who need this test are those who are showing
symptoms of hepatitis A. Persons who feel well should not be tested, even
if they recently ate green onions.
- What is immune globulin (often called IG or ISG) and who should
Immune globulin is a preparation of antibodies that can be given before
exposure to provide short-term protection against hepatitis A to reduce
the risk of infection among persons who have recently been exposed to
hepatitis A. For maximum protection immune globulin must be given within 2
weeks after exposure. Persons who have recently eaten green onions do not
need to get immune globulin unless they have been specifically exposed
within the previous 2 weeks to individuals or food involved in an outbreak
and believe by public health officials to have been potentially
- Are there treatments for hepatitis A?
There is no medication that treats hepatitis A. Some patients with
hepatitis A may need to be hospitalized to treat dehydration or liver
- Is there a vaccine for hepatitis A?
Yes, but it should be given before an exposure to work most effectively.
Hepatitis A vaccine has been licensed in the United States for use in
persons 2 years of age and older. The vaccine is recommended for persons
who are more likely to get hepatitis A virus infection or are more likely
to get seriously ill if they do get hepatitis A. More information on
vaccination can be found at http://www.cdc.gov/ncidod/diseases/hepatitis/a/faqa.htm.
CDC does not recommend that persons who have eaten green onions get
vaccinated, unless a healthcare professional recommends that they get
vaccinated because of other risk factors for hepatitis A.
- Have there been other recent outbreaks of hepatitis A caused by
contaminated food in the U.S.? Have these outbreaks been associated with
raw green onions?
Yes. Hepatitis A outbreaks associated with raw or undercooked green onions
served in restaurants occurred in Tennessee, North Carolina and Georgia in
September. The source of the green onions from the Tennessee outbreak
appears to be Mexico. The agency has been in consultation with Mexican
authorities to obtain their assistance in assessing the situation. In
addition, FDA is monitoring certain import entries of green onions for
evidence of potential contamination.