Yellow fever vaccine (Stamaril)

How does it work?

Stamaril is a yellow fever vaccine that contains a live, weakened form of the yellow fever virus. It works by stimulating the body's immune response to this virus, without causing the disease.

When the body is exposed to foreign organisms, such as bacteria and viruses, the immune system produces antibodies against them. Antibodies help the body recognise and kill the foreign organisms. They then remain in the body to help protect the body against future infections with the same organism. This is known as active immunity.

The immune system produces different antibodies for each foreign organism it encounters. This establishes a pool of antibodies that helps protect the body from various different diseases.

Vaccines contain extracts or inactivated forms of bacteria or viruses that cause disease. These altered forms of the organisms stimulate the immune system to produce antibodies against them, but don't actually cause disease themselves. The antibodies produced remain in the body so that if the organism is encountered naturally, the immune system can recognise it and attack it, thus preventing it from causing disease.

Each bacteria or virus stimulates the immune system to produce a specific type of antibody. This means that different vaccines are needed to prevent different diseases.

The yellow fever vaccine stimulates the immune system to produce antibodies against the yellow fever virus and is given to prevent this disease. One injection is needed and this provides protection against yellow fever from ten days after vaccination. The injection is usually administered under the skin (subcutaneously).

Protection lasts at least ten years, but a booster dose is needed after 10 years if protection against the disease is still required.

The yellow fever vaccine is not given routinely in the UK, but is recommended for people travelling to countries where the disease is found, such as parts of Africa and South America.

Most of these countries require you to have an International Certificate of Vaccination, stating that you have been vaccinated against yellow fever, in order to enter the country. Your doctor or pharmacist will be able to tell you which countries need this certificate. In order to be officially recognised, the vaccine must be administered at a designated vaccination centre and registered on an International Certificate. The International Certificate is valid for ten years from the tenth day after immunisation and immediately after a booster.

The vaccine is also recommended for laboratory workers who are handling infected material.

What is it used for?

  • Prevention of yellow fever.

This vaccine is not given routinely. It is only given to people who are at high risk of contracting yellow fever, such as travellers to or people living or working in high risk areas.

Warning!

  • This vaccine should only be given to children aged six to nine months of age if the risk of yellow fever is unavoidable, as there is a very small risk of the vaccine causing inflammation of the brain (encephalitis) in this age group.
  • This vaccine should only be given to people over 60 years of age if there is a considerable and unavoidable risk of yellow fever infection. This is because there is a higher risk of yellow fever vaccine-associated severe and potentially fatal disease in this older age group. See the side effects section below for more information.

Not to be used in

  • Babies under six months of age.
  • People who have ever had an anaphylactic allergic reaction to eggs or chicken protein.
  • People whose immune systems have a decreased ability to fight infection and disease, for example due to a genetic defect, or diseases such as HIV infection or immunodeficiency syndromes.
  • Symptomatic HIV infection.
  • People who are receiving, or who have recently received, treatment that suppresses the activity of the immune system, such high-dose corticosteroids, chemotherapy, radiotherapy, medicines to prevent transplant rejection or other immunosuppressants (see end of factsheet for more information).
  • People who have had their thymus gland removed and people with a history of thymus disorders, including cancer of the thymus gland.
  • Rare hereditary problems of fructose intolerance.
  • Sudden feverish illness (the vaccine should be postponed until after recovery).

This vaccine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction after having this vaccine inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain vaccines should not be used during pregnancy or breastfeeding. However, other vaccines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before having any vaccine.

  • The safety of this vaccine for use during pregnancy has not been established. It should only be given to pregnant women if there is a significant and unavoidable risk of exposure to yellow fever. Seek medical advice from your doctor.
  • It is not known if the yellow fever virus from this vaccine can pass into breast milk. This vaccine is not recommended for mothers who are breastfeeding unless there is a significant and unavoidable risk of exposure to yellow fever. Seek medical advice from your doctor.

Side effects

Vaccines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this vaccine. Just because a side effect is stated here does not mean that all people having this vaccine will experience that or any side effect.

Very common (affect more than 1 in 10 people)

  • Headache.
  • Pain, redness, bruising, swelling or hardening of the skin at the injection site.

Common (affect between 1 in 10 and 1 in 100 people)

  • Fever.
  • Feeling weak.
  • Feeling sick.
  • Diarrhoea.
  • Vomiting.
  • Aching muscles.

Uncommon (affect between 1 in 100 and 1 in 1000 people)

  • Abdominal pain.
  • Aching joints.

Unknown frequency

  • Swollen glands (lymph nodes).
  • An extreme allergic reaction (anaphylaxis).
  • Rash or hives.
  • Very rarely, disorders of the nervous system (neurotropic disease), which may have a fatal outcome. The risk is higher in people over 60 years of age. Symptoms usually appear within one month of vaccination and include high fever with headache that may progress to include one or more of confusion, lethargy, convulsions, inflammation of the brain or nerves, loss of movement or feeling in part or all of the body. Consult your doctor immediately if you develop any of these symptoms following vaccination.
  • Very rarely, disorders of the organs (viscerotropic disease), which may have a fatal outcome. The risk is higher in people over 60 years of age. Symptoms usually appear within 10 days of vaccination and may resemble symptoms of yellow fever infection. Symptoms generally begin with feeling tired, fever, headache, muscle pain and sometimes low blood pressure. These may progress to a severe muscle and liver disorder, drops in numbers of some types of blood cells resulting in unusual bruising or bleeding and increased risk of infections, and loss of normal functioning of the kidneys and lungs. Consult your doctor immediately if you develop any of these symptoms following vaccination.

The side effects listed above may not include all of the side effects reported by the vaccine's manufacturer.For more information about any other possible risks associated with this vaccine, please read the information provided with the vaccine or consult your doctor or pharmacist.

How can this vaccine affect other medicines or vaccines?

This vaccine must not be given to people whose immune system is underactive as a result of treatment with immunosuppressant medicines, because the vaccine could cause serious infection in these people. Immunosuppressant medicines include those listed below:

  • chemotherapy for cancer (this vaccine should be not be given until at least six months after the last chemotherapy dose)
  • generalised radiotherapy for cancer (this vaccine should be not be given until at least six months after the last radiotherapy dose)
  • high-dose corticosteroids, eg prednisolone (this vaccine should not be given until at least three months after stopping treatment with high doses of corticosteroids taken by mouth or injection)
  • immunosuppressants used to prevent rejection of organ transplants, eg azathioprine, ciclosporin, mycophenolate, tacrolimus (this vaccine should not be given until at least 12 months after stopping treatment)
  • other medicines that suppress the activity of the immune system, eg abatacept, adalimumab, anakinra, efalizumab, etanercept, infliximab, leflunomide.

If any other live virus vaccines are required, they should either be given at the same time as this one but at different sites, or separated by an interval of at least four weeks from this one.