Yellow Fever Vaccinations
With over 150+ clinics nationwide, CityDoc is your local leading provider of travel vaccinations.
Yellow Fever Information
Yellow fever is a potentially life threatening viral illness that is found in tropical areas of Africa and South and Central America. In the UK you can only obtain the yellow fever vaccination from a designated Yellow Fever Clinic.
It is transmitted by the bite of an infected mosquito. The mosquitoes feed during day light hours and are found in both urban and rural areas. Yellow fever cannot be transmitted directly form human to human contact. The mosquito that carries yellow fever virus is found in many countries of the world and thus, these countries have a potential to develop the disease in their mosquito population leading to outbreaks of this potentially deadly infection. Therefore, a number of countries, which do not have the disease may have a requirement for proof of vaccination against yellow fever before entry is allowed.
The incubation period from infection to developing yellow fever is 3 to 6 days.
Symptoms are divided into the acute phase and the toxic phase.
The acute phase presents with non specific symptoms of a viral infection such as high fever, headache, muscle ache, nausea and vomiting and loss of appetite.
Around 15% progress from the acute phase to the toxic phase. This consists of jaundice (yellow discolorations of the skin and eyes), liver and kidney failure, bleeding form the nose, eyes, stomach followed by death in 50% of cases within 10-14 days.
Symptoms include: high fever, generalised symptoms like violent headache, muscular pain, upset stomach and loss of fluid.
There is no treatment for yellow fever infection. Supportive and intensive medical care is required in the toxic phase to allow the body to clear the virus itself.
Yellow fever is entirely preventable illness. There is a safe and effective vaccine against the disease. In addition to vaccination, mosquito bite prevention measures, such as regular application of insect repellant, mosquito nets are also vital.
Yellow Fever Vaccine
Yellow fever Vaccination
The yellow fever vaccine contains a live, but weakened strain of the virus, which provides immunity against the infection for LIFE.
Since July 2016, the yellow fever vaccine certificate is also valid for “the life of the traveller”.
The vaccine can be given to adults and children from 9 months of age who are travelling to a country with a significant risk of yellow fever infection.
Additionally, the vaccine may be an entry requirement where:
- the country has a high risk of of the disease and require all entering to show evidence of vaccination.
- the country does not have yellow fever infection, but it has the mosquito (and monkey) population required for the disease to establish there. In this situation, the certificate is only required if you are arriving from a yellow fever country. The UK does not have yellow fever infection and nor does it have the mosquito. Therefore, you do not need to show a certificate if you are traveling directly from the UK or arriving back in the UK form a yellow fever country.
Yellow fever disease is the only one that has the international regulations against spread attached to it.
|Age||Method of Administration||Number of Doses|
|From 9 months of age||Subcutaneous injection to the thigh or deltoid region of the upper arm||1|
A single dose of the vaccine confers protection for life.
Booster doses are required in the following circumstances:
- The first dose of the vaccine was administered under 2 years of age
- The first dose of the vaccine was administered when pregnant
- The first dose of the vaccine was administered when immunosuppressed
The yellow fever vaccine should not be given to the following:
- Infants under the age of 9 months
- History of severe allergic reaction to a previous dose of the vaccine or any of it’s components
- History of severe allergic reaction to egg
- Anyone with an immune disorder, whether due to disease or drugs, such as steroids.
- Anyone with an unstable neurological condition, such as epilepsy not controlled on medication
- Pregnancy and breast feeding-see separate sections
- Previous history of disorder to the thymus gland (a organ in the chest). This includes thymectomy (where the gland has been removed) or Thymoma (a benign swelling of the gland).
- Acute illness with high fever (>38.5 Degrees Celsius)
Additionally, individuals over 60 years of age should have a careful assessment of their risk of contracting yellow fever infection before the vaccine should be given (see FAQ Section).
As the vaccine is live, there is a potential risk of the vaccine virus causing infection in the unborn baby. Therefore, vaccination should be avoided where possible during pregnancy. It is best not to travel to a country with a risk of yellow fever while pregnant.
However, if travel cannot be avoided, your CityDoc clinician will counsel on the risks from the vaccine versus the risk of the disease. As yellow fever infection can be fatal and there is no treatment for it, vaccination may be considered if travel cannot be avoided to a yellow fever country. There have been observational studies which have not demonstrated harm to the baby from the vaccine being administered during pregnancy.
Additionally, it is advised that pregnancy should not take place for 1 month after receiving the vaccine.
The vaccine is transmitted through breast milk to infants and there have been cases of breastfed infants (all under 1 month) being admitted to hospital with yellow fever infection after their mothers had received the vaccine.
Infants under 9 months of age are vulnerable to neurological side effects from the vaccine and hence we avoid vaccinating babies under 9 months unless there are exceptional reasons to do so and do not vaccinate infants under 6 months of age under any circumstances. Therefore, it is best not to travel to a yellow fever risk country while breast feeding infants under 9 months, as you may not be able to receive the vaccine yourself unless you discontinue breast feeding and your baby would not be protected against this potentially dangerous illness.
If travel is unavoidable and the risk of yellow fever infection is high, then vaccination can be given provided breast feeding is stopped for a period of 3 weeks.
Common Side Effects
Local reactions at the injection site-pain, redness, swelling.
Mild “Flu-like” symptoms such as headache, fever, muscles aches.
Interaction with Other Vaccines
The yellow fever vaccine can be given at the same time or any time before or after:
- Hepatitis A
- Hepatitis B
- Chickenpox vaccine
- BCG vaccine
Yellow Fever and MMR Vaccine
The yellow fever vaccine and MMR vaccines should be administered separated by an interval of 4 weeks.
If the vaccines are administered at the same time, then the vaccines interact resulting in reduced immune response to yellow fever, mumps and rubella. The response to measles is not effected.
If there is insufficient time before travel to respect the 4 week interval, then the vaccines can be given at any time, but further dose of MMR and/or yellow fever vaccine will be required.
Yellow Fever and Shingles Vaccine
There is limited evidence as to whether the vaccines interact and therefore, it is best to leave a 4 week interval between the vaccines wherever possible.
Yellow Fever is available at 100 + CityDoc locations.
The following locations do not have the yellow fever vaccine at present-(Expected by April 2017)
London– Enfield, Finchley Central, North Greenwich, Kentish Town, Walthamstow, Woolwich
South East – Basingstoke, Lindfield (Hayward’s Heath), Longfield, Sittingbourne
East -Dunstable, Elstree, Harlow, St Albans, Stevenage
Yorkshire – Crookes (Sheffield) West Midlands -Bromsgrove East Midlands – Hinkley, Leicester (Melton Rd)
Frequently Asked Questions
1) Is the Vaccine safe?
The yellow fever vaccine has been around for many decades and most people experience minor side effects from the vaccine. There are more serious side effects associated with the vaccine which are rare. Therefore, it is important that a careful risk assessment is made prior to anyone having the vaccine. Yellow fever illness can be fatal and is not treatable. Prevention is thus, vital and the vaccine is highly effective at preventing this disease.
2) What are the concerns with giving the vaccine to travellers over 60 years of age?
Yellow fever vaccine can cause two serious conditions (similar to the disease itself) that can affect the neurological system and other organ systems such as the liver and kidney. The incidence of these conditions is increased if the vaccine is given to individuals over 60 years of age. These conditions only occur when the vaccine is given for the first time.
The incidence of neurological complications (YEL-AND)are:
- Individuals under 60 years of age- 4 per million doses
- Individuals over 60 years-17 per million doses
The incidence of other organ complications (Yel-AVD) are:
- Individuals under 60 years of age- 3 per million doses
- Individuals over 60 years-20.5 per million doses
Therefore, it is important that the vaccine is only given if there is significant risk of yellow fever infection. If there is no risk of yellow fever infection, then a medical exemption can be issued.
3) What is a Medical Exemption for Yellow Fever Vaccine?
The medical exemption for yellow fever applies if a traveller has any of the exclusions to the vaccine detailed above.
A medical exemption can also be issued if there is no risk of yellow fever infection, but a significant risk of an adverse reaction to the vaccine. For example, in those individuals over 60 years of age, receiving the yellow fever vaccine for the first time.
The medical exemption is a clinical decision based on a thorough risk assessment by the Travel Health Specialist. Yellow fever is a life threatening infection without treatment and thus, if there is a risk of yellow fever infection and no exclusions then the medical exemption cannot be issued.
The medical exemption is valid for a single trip only.
4) How long does the yellow fever vaccine take to become effective?
The vaccine and the certificate are valid from 10 days after the vaccine has been given.
If you are travelling in less than 10 days, you must ensure that you are vigilant with mosquito bite prevntion measures until the vaccine has become effective.
The valid from date on the certificate must be written as 10 days. Therefore, if you traveling before this time to a country that requires you to show proof of vaccinaiton, it is up to the border official if you are allowed entry. The valid form date cannot be altered as it is a legal document.
5) What happens if I lose my certificate and require it for entry to my destination?
If your certificate was issued at a CityDoc clinic, we will have the details of the vaccine recorded and can issue you a duplicate certificate.
If the vaccine was administered at another travel clinic, in order we us to issue a duplicate certificate, we would need the vaccine details, including the date it was given, the vaccine batch number and expiry date. Without this information, a duplicate cannot be issued and revaccination may be required.
The international certificate can only be issued following vaccinaiton with yellow fever.
6) Is it harmful to have further doses of the vaccine?
If you require revaccination, it is not harmful as you would already have antibodies from the previous vaccine. This means you are unlikely to get significant or serious side effects and your immune system will be boosted.
7) Is a new certificate required if the vaccine was given before July 2016 and therefore, is only valid for 10 years?
If you have a valid vaccine certificate, even if this has written a 10 year expiry date, you do not need a new certificate. This is because form July 2016, the certificate no longer has an expiry date and thus, all countries have to accept the validity of the certificate as lifelong. You simply need to show your current certificate to obtain entry.
Please note-If you do not have your original certificate and the vaccine was administered before July 2016, the duplicate certificate issued will still carry the expiry date. However, the same rule applies as above.
Only certificates issued following yellow fever vaccinations received after July 2016 will carry the lifelong validity.
8) As it is a live vaccine, am I infectious after vaccination?
There is no evidence that the vaccine virus shed and therefore, you cannot transmit the disease.
9) What happens if I am travelling to a country with yellow fever infection and have an immune condition?
The yellow fever vaccine cannot be give if you have suppressed immune system. This includes:
- Chemotherapy or radiotherapy for cancer within last 6 months
- Taking immunosuppressant medications withint the last 6 months, like treatments for inflammatory arthritis such as oral steroids.
- Disorders of the immune system, such as severe HIV infection.
If the vaccine is required for risk of yellow fever infection, the advise would be to avoid travelling due to the risk and severity of yellow fever infection.
If the vaccine is required for entry purposes to the country only and there is no risk of yellow fever, a medical exemption can be issued.
11) Can the yellow fever vaccine be given to Individuals with HIV Infection?
As HIV infection is a spectrum of immunosuppression with some patients, especially those on treatment having near normal immune systems, the decision to give the vaccine would be based on current immune cell levels (CD4 count).
If the vaccine is required for travel to a high risk country for yellow fever, then the vaccine can be considered providing the following criteria are met:
- Laboratory evidence of blood test showing CD4 count of >200 within the last 4 weeks; and/or
- Letter from HIV specialist showing CD4 count >200 and asymptomatic from infection.
The vaccine should be given 2 weeks before travel to monitor and manage any adverse effects.
12) Can the vaccine be given to infants under 9 months for travel to high risk yellow fever countries?
Infants under 9 months are at increased risk of vaccine associated encephalitis (inflammation of the brain), a potentially life threatening condition.
This risk is highest in infants under 6 months of age and thus, the vaccine MUST never be given to this group.
The vaccine can only be considered in infants between 6-9 months of age in exceptional circumstances, such as travel during an outbreak or epidemic. However, we would need to discuss the exact itinerary details with NaTHNac and a decision made on their advice.