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.

Remember, vaccines are continually monitored for safety, and like any medication, vaccines can cause side effects. However, a decision not to immunize a child also involves risk and could put the child and others who come into contact with him or her at risk of contracting a potentially deadly disease.

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 Anthrax VIS [PDF - 45KB]
(This information taken from Anthrax VIS dated 4/23/03. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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

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 DTaP VIS [PDF - 43KB]
(This information taken from DTaP VIS dated 5/17/07. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Hepatitis A vaccine side-effects

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 Hepatitis A VIS [PDF - 68KB]
(This information taken from Hepatitis A VIS dated 3/27/06. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Hepatitis B vaccine side-effects

What are the risks from hepatitis B vaccine?

Hepatitis B is a very safe vaccine. Most people do not have any problems with it.

Mild problems reported

• Soreness where the shot was given (up to about 1 person 4)
• Temperature of 99.9°F or higher (up to about 1
  person in 15).

Severe problems are extremely rare. Severe allergicreactions are believed to occur about once in 1.1 million doses.

A vaccine, like any medicine, could cause a serious reaction. But the risk of a vaccine causing serious harm, or death, is extremely small. More than 100 million people have gotten hepatitis B vaccine in theUnited States.

This information was taken directly from the Hepatitis B VIS [PDF - 66KB]
(This information taken from Hepatitis B VIS dated 7/18/07. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Hib vaccine side-effects

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 Hib VIS [PDF - 65KB]
(This information taken from Hib VIS dated 12/16/98. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 HPV VIS [PDF - 47KB]
(This information taken from HPV VIS dated 2/2/07. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Influenza (inactivated) vaccine side-effects

What are the risks from inactivated influenza vaccine? UDPATED Aug 2009

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
• hoarseness, sore or red eyes, cough, itchiness
• 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 usually 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 GBS. However, if there is a risk of GBS 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 Inactivated Influenza VIS [PDF - 38KB]
(This information taken from Inactivated Influenza VIS dated 8/11/09. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Influenza (live) vaccine side-effects

What are the risks from LAIV? UDPATED Aug 2009

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.

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 2-17 years of age have reported mild reactions, including:

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

Some adults 18-49 years of age have reported:

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

Severe problems:

• Life-threatening allergic reactions from vaccines are very rare. If they do occur, it is usually within a few minutes to a few hours after the shot.
• If rare reactions occur with any product, they may not be identified until thousands, or millions, of people have used it. Millions of 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 LAIV VIS [PDF - 37KB]
(This information taken from Live Influenza VIS dated 8/11/09. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 JE VIS [PDF - 55KB]
(This information taken from Japanese Encephalitis VIS dated 5/11/05. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 Lyme VIS [PDF - 40KB]
(This information taken from Lyme VIS effective 11/1/99. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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

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

Note: The first dose of MMRV vaccine has been associated with rash and higher rates of fever than MMR and varicella vaccines given separately. Rash has been reported in about 1 person in 20 and feverin about 1 person in 5. Seizures caused by a fever are also reported more often after MMRV. These usually occur 5-12 days after the first dose.

This information was taken directly from the MMR VIS [PDF - 54KB]
(This information taken from MMR VIS dated 3/13/08. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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

As many as half the 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 Meningococcal VIS [PDF - 62KB]
(This information taken from Meningococcal VIS dated 1/28/08. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

PCV7 vaccine side-effects
(Pneumococcal Conjugate Vaccine)

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 PCV VIS [PDF - 41KB]
(This information taken from PCV VIS dated 12/9/08. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

PPSV23 vaccine side-effects
(Pneumococcal Polysaccharide)

What are the risks from PPSV?

About half of people who get PPSV have mild side effects, such as redness or pain where the shot is given.

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

A vaccine, like any medicine, could cause a serious reaction. But the risk of a vaccine causing serious harm, or death, is extremely small.

This information was taken directly from the PPSV VIS [PDF - 121KB]
(This information taken from PPSV VIS dated 4/16/09. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Polio vaccine side-effects

What are the risks from IPV?

Some people who get Inactivated Polio Vaccine (IPV) get a sore spot where the shot was 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. The risk of a polio shot causing serious harm, or death, is extremely small.

This information was taken directly from the IPV VIS [PDF - 60KB]
(This information taken from IPV VIS dated 1/1/00. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 Rabies VIS [PDF - 58KB]
(This information taken from Rabies VIS dated 1/12/06. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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.

Most babies who get rotavirus vaccine do not have any problems with it.

Mild problems

Babies may be slightly more likely to be irritable, or to have mild, temporary diarrhea or vomiting after getting a dose of rotavirus vaccine than babies who did not get the vaccine.

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

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 Rotavirus VIS [PDF - 44KB]
(This information taken from Rotavirus VIS dated 4/28/08. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 Shingles VIS [PDF - 47KB]
(This information taken from Shingles VIS dated 9/11/06. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 Smallpox VIS [PDF - 284KB]
(This information taken from Smallpox VIS dated 12/11/02. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Td (Adult Tetanus & Diphtheria) vaccine AND
Tdap vaccine (Combined Tetanus, Diphtheria & Pertussis)

What are the risks from Tdap and Td vaccines?

With a vaccine (as with any medicine) there is always a small risk of a life-threatening allergic reaction or other serious problem.

Getting tetanus, diphtheria or pertussis would be much more likely to lead to severe problems than getting either vaccine. Problems reported after Td and Tdap vaccines are listed below.

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

Tdap

• 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)
• Chills, body aches, sore joints, rash, swollen glands (uncommon)

Td

• Pain (up to about 8 in 10)
• Redness or swelling (up to about 1 in 3)
• Mild fever (up to about 1 in 15)
• Headache or tiredness (uncommon)

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

Tdap

• 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)
• Headache (1 in 300)
• Nausea, vomiting, diarrhea, stomach ache (up to 3 in 100 adolescents and 1 in 100 adults)

Td

• Fever over 102°F (rare)

Tdap or Td

• Extensive swelling of the arm where the shot was given (up to about 3 in 100).

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

Tdap

• Two adults had nervous system problems after getting the vaccine during clinical trials. These may or may not have been caused by the vaccine. These problems went away on their own and did not cause any permanent harm.

Tdap or Td

• Swelling, severe pain, and redness in the arm where the shot was given (rare).

A severe allergic reaction could occur after any vaccine. They are estimated to occur less than once in a million doses.

This information was taken directly from the Td-Tdap VIS [PDF - 47KB]
(This information taken from Td-Tdap VIS dated 11/18/08. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 Typhoid VIS [PDF - 47KB]
(This information taken from Typhoid VIS dated 5/19/04. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

Varicella (Chickenpox) vaccine side-effects

What are the risks from chickenpox vaccine?

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.

Getting chickenpox vaccine is much safer than getting chickenpox disease. Most people who get chickenpox vaccine do not have any problems with it. Reactions are usually more likely after the first dose than after the second.

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 25). It is possible for these people to infect other members of their household, but this is extremely rare.

Note: The first dose of MMRV vaccine has been associated with rash and higher rates of fever than MMR and varicella vaccines given separately. Rash has been reported in about 1 person in 20 and fever in about 1 person in 5. Seizures caused by a fever are also reported more often after MMRV. These usually occur 5-12 days after the first dose.

Moderate Problems

• Seizure (jerking or staring) caused by fever (very rare).

Severe Problems

• Pneumonia (very rare)

Other serious problems, including severe brain reactions and low blood count, have been reported after chickenpox vaccination. These happen so rarely 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 Varicella VIS [PDF - 43KB]
(This information taken from Varicella VIS dated 3/13/08. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

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 Yellow Fever VIS [PDF - 36KB]
(This information taken from Yellow Fever VIS dated 11/9/04. If the actual VIS is more recent than this date, the information on this page needs to be updated.)

What if there is a moderate or severe reaction?

What should I look for?

• Any unusual condition, such as a high fever, weakness, or behavior changes. Signs of a serious allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heart beat or dizziness.

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 your provider 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.hhs.gov, 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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