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Department of Health and Human Services
Centers for Disease Control and Prevention


Vaccines & Immunizations

Basics and Common Questions:

Possible Side-effects from Vaccines

Any vaccine can cause side effects. For the most part these are minor (for example, a sore arm or low-grade fever) and go away within a few days. Listed below are vaccines licensed in the United States and side effects that have been associated with each of them. This information is copied directly from CDC's Vaccine Information Statements, which in turn are derived from the Advisory Committee on Immunization Practices (ACIP) recommendations for each vaccine.

Anthrax vaccine side-effects

What are the risks from anthrax vaccine?

Getting anthrax disease is much more dangerous than any risk from the vaccine.

Like any medicine, a vaccine is capable of causing serious problems, such as severe allergic reactions. The risk of anthrax vaccine causing serious harm, or death, is extremely small.

Mild Problems

  • Soreness, redness, or itching where the shot was given (about 1 out of 10 men, about 1 out of 6 women)
  • A lump where the shot was given (about 1 person out of 2)
  • Muscle aches or joint aches (about 1 person out of 5)
  • Headaches (about 1 person out of 5)
  • Fatigue (about 1 out of 15 men, about 1 out of 6 women)
  • Chills or fever (about 1 person out of 20)
  • Nausea (about 1 person out of 20).

Moderate Problems

  • Large areas of redness where the shot was given (up to 1 person out of 20).

Severe Problems

  • Serious allergic reaction (very rare - less than once in 100,000 doses).
  • As with any vaccine, other severe problems have been reported. But these events appear to occur no more often among anthrax vaccine recipients than among unvaccinated people.
  • There is no evidence that anthrax vaccine causes sterility, birth defects, or long-term health problems.

    Independent civilian committees have not found anthrax vaccination to be a factor in unexplained illnesses among Gulf War veterans.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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DTaP vaccine side-effects
(Diphtheria, Tetanus, and acellular Pertussis)

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What are the risks from DTaP vaccine?

Getting diphtheria, tetanus or pertussis disease is much riskier than getting DTaP vaccine.

However, a vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of DTaP vaccine causing serious harm, or death, is extremely small.

Mild Problems (Common)

  • Fever (up to about 1 child in 4)
  • Redness or swelling where the shot was given (up to about 1 child in 4)
  • Soreness or tenderness where the shot was given (up to about 1 child in 4)

These problems occur more often after the 4th and 5th doses of the DTaP series than after earlier doses.

Sometimes the 4th or 5th dose of DTaP vaccine is followed by swelling of the entire arm or leg in which the shot was given, for 1 to 7 days (up to about 1 child in 30).

Other mild problems include:

  • Fussiness (up to about 1 child in 3)
  • Tiredness or poor appetite (up to about 1 child in 10)
  • Vomiting (up to about 1 child in 50)

These problems generally occur 1 to 3 days after the shot.

Moderate Problems (Uncommon)

  • Seizure (jerking or staring) (about 1 child out of 14,000)
  • Non-stop crying, for 3 hours or more (up to about 1 child out of 1,000)
  • High fever, 105 degrees Fahrenheit or higher (about 1 child out of 16,000)

Severe Problems (Very Rare)
Serious allergic reaction (less than 1 out of a million doses) Several other severe problems have been reported after DTaP vaccine. These include:

  • Long-term seizures, coma, or lowered consciousness
  • Permanent brain damage.

These are so rare it is hard to tell if they are caused by the vaccine.

Controlling fever is especially important for children who have had seizures, for any reason. It is also important if another family member has had seizures.

You can reduce fever and pain by giving your child an aspirin-free pain reliever when the shot is given, and for the next 24 hours, following the package instructions.

This information was taken directly from the Vaccination Information StatementAdobe Acrobat print-friendly PDF file

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Hepatitis A vaccine side-effects

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What are the risks from hepatitis A vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of hepatitis A vaccine causing serious harm, or death, is extremely small.

Getting hepatitis A vaccine is much safer than getting the disease.

Mild problems

  • soreness where the shot was given (about 1 out of 2 adults, and up to 1 out of 6 children)
  • headache (about 1 out of 6 adults and 1 out of 25 children)
  • loss of appetite (about 1 out of 12 children)
  • tiredness (about 1 out of 14 adults)

If these problems occur, they usually last 1 or 2 days.

Severe problems

  • serious allergic reaction, within a few minutes to a few hours of the shot (very rare)

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Hepatitis B vaccine side-effects

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What are the risks from hepatitis B vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of hepatitis B vaccine causing serious harm, or death, is extremely small.

Getting hepatitis B vaccine is much safer than getting hepatitis B disease.

Most people who get hepatitis B vaccine do not have any problems with it.

Mild problems

  • soreness where the shot was given, lasting a day or two (up to 1 out of 11 children and adolescents, and about 1 out of 4 adults)
  • mild to moderate fever (up to 1 out of 14 children and adolescents and 1 out of 100 adults)

Severe problems

  • serious allergic reaction (very rare)

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Hib vaccine side-effects

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What are the risks from Hib (Haemophilus influenzae type b) vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of Hib vaccine causing serious harm or death is extremely small.

Most people who get Hib vaccine do not have any problems with it.

Mild Problems

  • Redness, warmth, or swelling where the shot was given (up to 1 out of 4 children)
  • Fever over 101 degrees Fahrenheit (up to 1 out of 20 children)

If these problems happen, they usually start within a day of vaccination. They may last 2 to 3 days.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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HPV vaccine side-effects
(Human Papillomavirus vaccine)

What are the risks from HPV vaccine?

HPV vaccine does not appear to cause any serious side effects.

However, a vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of any vaccine causing serious harm, or death, is extremely small.

Several mild problems may occur with HPV vaccine:

  • Pain at the injection site (about 8 people in 10)
  • Redness or swelling at the injection site (about 1 person in 4)
  • Mild fever (100 degrees Fahrenheit) (about 1 person in 10)
  • Itching at the injection site (about 1 person in 30)
  • Moderate fever (102 degrees Fahrenheit) (about 1 person in 65)

These symptoms do not last long and go away on their own.

Life-threatening allergic reactions from vaccines are very rare. If they do occur, it would be within a few minutes to a few hours after the vaccination.

Like all vaccines, HPV vaccine will continue to be monitored for unusual or severe problems.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Influenza (inactivated) vaccine side-effects

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What are the risks from inactivated influenza vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small.

Serious problems from influenza vaccine are very rare. The viruses in inactivated influenza vaccine have been killed, so you cannot get influenza from the vaccine.

Mild problems:

  • soreness, redness, or swelling where the shot was given
  • fever
  • aches

If these problems occur, they usually begin soon after the shot and last 1 to 2 days.

Severe problems:

  • Life-threatening allergic reactions from vaccines are very rare. If they do occur, it is within a few minutes to a few hours after the shot.
  • In 1976, a certain type of influenza (swine flu) vaccine was associated with Guillain-Barré Syndrome (GBS). Since then, flu vaccines have not been clearly linked to G.B.S. However, if there is a risk of G.B.S. from current flu vaccines, it would be no more than 1 or 2 cases per million people vaccinated. This is much lower than the risk of severe influenza, which can be prevented by vaccination.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Influenza (live) vaccine side-effects

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What are the risks from LAIV?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. However, the risk of a vaccine causing serious harm, or death, is extremely small.

Live influenza vaccine viruses rarely spread from person to person. Even if they do, they are not likely to cause illness.

LAIV is made from weakened virus and does not cause influenza. The vaccine can cause mild symptoms in people who get it (see below).

Mild problems:
Some children and adolescents 5 through 17 years of age have reported mild reactions, including:

  • runny nose, nasal congestion or cough
  • headache and muscle aches
  • fever
  • abdominal pain or occasional vomiting or diarrhea

Some adults 18 through 49 years of age have reported:

  • runny nose or nasal congestion
  • sore throat
  • cough, chills, tiredness/weakness
  • headache

These symptoms did not last long and went away on their own. Although they can occur after vaccination, they may not have been caused by the vaccine.

Severe problems:

  • Life-threatening allergic reactions from vaccines are very rare. If they do occur, it is within a few minutes to a few hours after the vaccination.
  • If rare reactions occur with any new product, they may not be identified until thousands, or millions, of people have used it. Over four million doses of LAIV have been distributed since it was licensed, and no serious problems have been identified. Like all vaccines, LAIV will continue to be monitored for unusual or severe problems.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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JE vaccine side-effects
(Japanese Encephalitis)

What are the risks from Japanese encephalitis vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small.

Mild Problems

  • soreness, redness, or swelling where the shot was given (about 1 person in 5)
  • fever, headache, muscle pain, abdominal pain, rash, chills, nausea/vomiting, or dizziness (about 1 person in 10)

If these problems occur, they usually begin soon after the shot and last for a couple of days.

Moderate or Severe Problems

Serious allergic reactions including rash; swelling of the hands and feet, face, or lips; and breathing difficulty. These have occurred within minutes to as long as 10 to 17 days after receiving the vaccine, usually about 48 hours after the vaccination. (About 60 per 10,000 people vaccinated have had allergic reactions to JE vaccine.)

Other severe problems, such as seizures or nervous system problems, have been reported. These are rare (probably less than 1 per 50,000 people vaccinated).

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Lyme vaccine side-effects

What are the risks from Lyme disease vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small.

In clinical trials, Lyme disease vaccine has been associated only with mild problems, such as soreness where the shot is given.

Most people who get Lyme disease vaccine do not have any problems with it.

Mild Problems

  • soreness where the shot was given (about 1 person out of 4)
  • redness or swelling where the shot was given (less than 1 person out of 50)
  • muscle aches, joint pain, fever, chills (about 1 person out of 15 or less)

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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MMR vaccine side-effects
(Measles, Mumps, and Rubella)

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What are the risks from MMR vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of MMR vaccine causing serious harm, or death, is extremely small.

Getting MMR vaccine is much safer than getting any of these three diseases.

Most people who get MMR vaccine do not have any problems with it.

Mild Problems

  • Fever (up to 1 person out of 6)
  • Mild rash (about 1 person out of 20)
  • Swelling of glands in the cheeks or neck (rare)
    If these problems occur, it is usually within 7-12 days after the shot. They occur less often after the second dose.

Moderate Problems

  • Seizure (jerking or staring) caused by fever (about 1 out of 3,000 doses)
  • Temporary pain and stiffness in the joints, mostly in teenage or adult women (up to 1 out of 4)
  • Temporary low platelet count, which can cause a bleeding disorder (about 1 out of 30,000 doses)

Severe Problems (Very Rare)

  • Serious allergic reaction (less than 1 out of a million doses)
  • Several other severe problems have been known to occur after a child gets MMR vaccine. But this happens so rarely, experts cannot be sure whether they are caused by the vaccine or not. These include:
    • Deafness
    • Long-term seizures, coma, or lowered consciousness
    • Permanent brain damage

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Meningococcal vaccine side-effects

What are the risks from meningococcal vaccines?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of the meningococcal vaccine causing serious harm, or death, is extremely small.

Mild problems

Up to about half of people who get meningococcal vaccines have mild side effects, such as redness or pain where the shot was given.

If these problems occur, they usually last for 1 or 2 days. They are more common after MCV4 than after MPSV4.

A small percentage of people who receive the vaccine develop a fever.

Severe problems

  • Serious allergic reactions, within a few minutes to a few hours of the shot, are very rare.
  • A serious nervous system disorder called Guillain-Barré Syndrome (or GBS) has been reported among some people who received MCV4. This happens so rarely that it is currently not possible to tell if the vaccine might be a factor. Even if it is, the risk is very small.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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PCV7 vaccine side-effects
(Pneumococcal Conjugate Vaccine)

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What are the risks from pneumococcal conjugate vaccine?

In studies (nearly 60,000 doses), pneumococcal conjugate vaccine was associated with only mild reactions:

  • Up to about 1 infant out of 4 had redness, tenderness, or swelling where the shot was given.
  • Up to about 1 out of 3 had a fever of over 100.4 degrees Fahrenheit, and up to about 1 in 50 had a higher fever (over 102.2 degrees Fahrenheit).
  • Some children also became fussy or drowsy, or had a loss of appetite.

So far, no moderate or severe reactions have been associated with this vaccine. However, a vaccine, like any medicine, could cause serious problems, such as a severe allergic reaction. The risk of this vaccine causing serious harm, or death, is extremely small.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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PPV23 vaccine side-effects
(Pneumococcal Polysaccharide)

What are the risks from PPV?

PPV is a very safe vaccine.
About half of those who get the vaccine have very mild side effects, such as redness or pain where the shot is given.

Less than 1% develop a fever, muscle aches, or more severe local reactions.

Severe allergic reactions have been reported very rarely.

As with any medicine, there is a very small risk that serious problems, even death, could occur after getting a vaccine.

Getting the disease is much more likely to cause serious problems than getting the vaccine.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Polio vaccine side-effects

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What are the risks from IPV?

In countries using IPV, no increased risk for serious adverse events has been observed. Some people who get IPV get a sore spot where the shot is given. The vaccine used today has never been known to cause any serious problems, and most people don't have any problems at all with it.

However, a vaccine, like any medicine, could cause serious problems, such as a severe allergic reaction. IPV should not be administered to persons who have experienced a severe allergic reaction after a previous dose of IPV or to streptomycin, polymyxin B, and neomycin. The risk of a polio shot causing serious harm, or death, is extremely small.

Reporting reactions helps experts learn about possible problems with vaccines.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Rabies vaccine side-effects

What are the risks from rabies vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small. Serious problems from rabies vaccine are very rare.

Mild problems:

  • soreness, redness, swelling, or itching where the shot was given (30% - 74%)
  • headache, nausea, abdominal pain, muscle aches, dizziness (5% - 40%)

Moderate problems:

  • hives, pain in the joints, fever (about 6% of booster doses)
  • illness resembling Guillain-Barré Syndrome (GBS), with complete recovery (very rare)

Other nervous system disorders have been reported after rabies vaccine, but this happens so rarely that it is not known whether they are related to the vaccine.

NOTE: Several brands of rabies vaccine are available in the United States, and reactions may vary between brands. Your provider can give you more information about a particular brand.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Rotavirus vaccine side-effects

What are the risks from rotavirus vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of rotavirus vaccine causing serious harm, or death, is extremely small.

Getting rotavirus vaccine is much safer than getting the disease.

Mild problems

Children are slightly (1 to 3 percent) more likely to have mild, temporary diarrhea or vomiting within 7 days after getting a dose of rotavirus vaccine than children who have not gotten the vaccine.

Moderate or severe reactions have not been associated with this vaccine.

If rare reactions occur with any new product, they may not be identified until thousands, or millions, of people have used it. Like all vaccines, rotavirus vaccine will continue to be monitored for unusual or severe problems.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Shingles (Herpes Zoster) vaccine side-effects

What are the risks from shingles vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. However, the risk of a vaccine causing serious harm, or death, is extremely small.

No serious problems have been identified with shingles vaccine.

Mild Problems

  • Redness, soreness, swelling, or itching at the site of the injection (about 1 person in 3).
  • Headache (about 1 person in 70).

Like all vaccines, shingles vaccine is being closely monitored for unusual or severe problems.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Smallpox (Vaccinia) vaccine side-effects

What are the risks from smallpox vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of smallpox vaccine causing serious harm, or death, is very small.

Mild to Moderate Problems

  • Mild rash, lasting 2-4 days.
  • Swelling and tenderness of lymph nodes, lasting 2-4 weeks after the blister has healed.
  • Fever of over 100 degrees fahrenheit (about 70% of children, 17% of adults) or over 102 degrees Fahrenheit (about 15%-20% of children, under 2% of adults).
  • Secondary blister elsewhere on the body (about 1 per 1,900).

Moderate to Severe Problems

  • Serious eye infection , or loss of vision, due to spread of vaccine virus to the eye.
  • Rash on entire body (as many as 1 per 4,000).
  • Severe rash on people with eczema (as many as 1 per 26,000).
  • Encephalitis (severe brain reaction), which can lead to permanent brain damage (as many as 1 per 83,000).
  • Severe infection beginning at the vaccination site (as many as 1 per 667,000, mostly in people with weakened immune systems).
  • Death (1-2 per million, mostly in people with weakened immune systems).

For every million people vaccinated, between 14 and 52 could have a life-threatening reaction to smallpox vaccine.

People who come in direct contact with the vaccination site of a vaccinated person, or with materials that have touched the site, can also have a reaction. This is from exposure to virus from the vaccination site.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Td vaccine side-effects
(Adult Tetanus and Diphtheria)

What are the risks from Td vaccine?

As with any medicine, there are very small risks that serious problems, even death, could occur after getting a vaccine.The risks from the vaccine are much smaller than the risks from the diseases if people stopped using vaccine.

Almost all people who get Td have no problems from it.

Mild problems

If these problems occur, they usually start within hours to a day or two after vaccination. They may last 1-2 days:

  • soreness, redness, or swelling where the shot was given

These problems can be worse in adults who get Td vaccine very often.  Acetaminophen or ibuprofen (non-aspirin) may be used to reduce soreness.

Severe problems

These problems happen very rarely:

  • serious allergic reaction
  • deep, aching pain and muscle wasting in upper arm(s). This starts 2 days to 4 weeks after the shot, and may last many months.

What to do if there is a serious reaction:

  • Call a doctor or get the person to a doctor right away,
  • Write down what happened and the date and time it happened.
  • Ask your doctor, nurse, or health department to file a Vaccine Adverse Event Report form or call: (800) 822-7967 (toll-free)

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Tdap vaccine side-effects
(Combined Tetanus, Diphtheria and Pertussis)

What are the risks from Tdap vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. However, the risk of a vaccine causing serious harm, or death, is extremely small.

If rare reactions occur with any new product, they may not be identified until many thousands, or even millions, of people have used the product. Like all vaccines, Tdap is
being closely monitored for unusual or severe problems.

Clinical trials (testing before the vaccine was licensed) involved about 4,200 adolescents and about 1,800 adults. The following problems were reported. These are similar
to problems reported after Td vaccine.

Mild Problems
(Noticeable, but did not interfere with activities)

  • Pain (about 3 in 4 adolescents and 2 in 3 adults)
  • Redness or swelling (about 1 in 5)
  • Mild fever of at least 100.4°F (up to about 1 in 25 adolescents and 1 in 100 adults)
  • Headache (about 4 in 10 adolescents and 3 in 10 adults)
  • Tiredness (about 1 in 3 adolescents and 1 in 4 adults)
  • Nausea, vomiting, diarrhea, stomach ache (up to 1 in 4 adolescents and 1 in 10 adults)
  • Other mild problems reported include chills, body aches, sore joints, rash, and swollen lymph glands.

Moderate Problems
(Interfered with activities, but did not require medical attention)

  • Pain at the injection site (about 1 in 20 adolescents and 1 in 100 adults)
  • Redness or swelling (up to about 1 in 16 adolescents and 1 in 25 adults)
  • Fever over 102°F (about 1 in 100 adolescents and 1 in 250 adults)
  • Nausea, vomiting, diarrhea, stomach ache (up to 3 in 100 adolescents and 1 in 100 adults)

Severe Problems
(Unable to perform usual activities; required medical attention)

  • None were seen among adolescents.
  • In the adult clinical trial, two adults had nervous system problems after getting the vaccine. These may or may not have been caused by the vaccine. They went away on their own and did not cause any permanent harm.
  • A severe allergic reaction could occur after any vaccine. They are estimated to occur less than once in a million doses. A person who gets these diseases is much more likely to have severe complications than a person who gets Tdap vaccine.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Typhoid vaccine side-effects

What are the risks from typhoid vaccine?

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small. Serious problems from either of the two typhoid vaccines are very rare.

Inactivated Typhoid Vaccine (Shot)

  Mild Reactions

  • Fever (up to about 1 person per 100).
  • Headache (up to about 3 people per 100).
  • Redness or swelling at the site of the injection (up to 7 people per 100).
Live Typhoid Vaccine (Oral)

  Mild Reactions

  • Fever or headache (up to about 5 people per 100).
  • Abdominal discomfort, nausea, vomiting, or rash (rare).

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Varicella (Chickenpox) vaccine side-effects

What are the risks from chickenpox vaccine?

Getting chickenpox vaccine is much safer than getting chickenpox disease. Most people who get chickenpox vaccine do not have any problems with it.

However, a vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of chickenpox vaccine causing serious harm, or death, is extremely small.

Mild Problems

  • Soreness or swelling where the shot was given (about 1 out of 5 children and up to 1 out of 3 adolescents and adults)
  • Fever (1 person out of 10, or less)
  • Mild rash, up to a month after vaccination (1 person out of 20, or less). It is possible for these people to infect other members of their household, but this is extremely rare.

Note: MMRV vaccine has been associated with higher rates of fever (up to about 1 person in 5) and measles-like rash (about 1 person in 20) compared with MMR and varicella vaccines given separately.

Moderate Problems

  • Seizure (jerking or staring) caused by fever (less than 1 person out of 1,000).

Severe Problems

  • Pneumonia (very rare)

Other serious problems, including severe neurological problems (brain reactions) and low blood count, have been reported after chickenpox vaccination. These happen so rarely, however, that experts cannot tell whether they are caused by the vaccine or not. If they are, it is extremely rare.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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Yellow Fever vaccine side-effects

What are the risks from Yellow Fever vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small.

Reactions are less likely to occur after a booster dose of yellow fever vaccine than after the first dose.

Mild problems:

  • soreness, redness, or swelling where the shot was given
  • fever
  • aches

If these problems occur, they usually begin soon after the shot and last for 5 to 10 days. In studies, they occurred in as many as 25 percent of vaccine recipients.

Severe problems (estimates based on passive reporting):

  • Life-threatening allergic reaction (approximately 1 reported per 131,000 doses).
  • Severe nervous system reactions (approximately 1 reported per 150,000 to 250,000 doses).
  • Life-threatening severe illness with major organ system failure (approximately 1 reported per 200,000 to 300,000 doses, or 1 reported per 40,000 to 50,000 doses in people 60 years of age and older). More than half of the people who suffer these side effects die.

This information was taken directly from the Vaccine Information Statement Adobe Acrobat print-friendly PDF file

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What if there is a moderate or severe reaction?

What should I look for?

  • Look for any unusual condition, such as a high fever, behavior changes, or flu-like symptoms that occur 1 to 30 days after vaccination. Signs of an allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat, or dizziness within a few minutes to a few hours after the shot.

What should I do?

  • Call a doctor, or get the person to a doctor right away.
  • Tell your doctor what happened, the date and time it happened, and when the vaccination was given.
  • Ask the clinic where you received the vaccine to save any left over vaccine and the vaccine vial, and record the lot number.
  • Ask your doctor, nurse, or health department to report the reaction by filing a Vaccine Adverse Event Reporting System (VAERS) form.
    Or you can file this report through the VAERS website at www.vaers.org, or by calling 1-800-822-7967. VAERS does not provide medical advice. Reporting reactions helps experts learn about possible problems with vaccines.

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This page last modified on June 12, 2007
Content last reviewed on May 24, 2007
Content Source: National Center for Immunization and Respiratory Diseases

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