CityDoc-UK’s Vaccine Specialists
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Chickenpox is a highly infectious disease, caused by the virus, Varicella Zoster. It mainly affects children under 10 years of age, where risk of serious complications are not as common as in adults.
Chickenpox virus is spread through personal contact with an infected individual or through coughing and sneezing. It is possible to develop Chickenpox from contact with someone who has shingles. However, you cannot contract shingles directly form someone who is infected with Chickenpox.
The virus is most infectious 1-2 days before the rash occurs and for around 5 days after (or until the rash crusts over). 90% of household contacts of someone infected with Chickenpox will catch the infection if they have never had it before.
Chickenpox has an incubation period of 3 weeks. This is the time taken from contracting the infection to developing the symptoms.
The classic symptom is a rash, which is very itchy and can be widespread affecting the face, chest, arms and legs. Sometimes, the blisters can occur inside the mouth. There is often fever and cold symptoms also. The symptoms tend to improve after 1 week.
The illness can vary from mild symptoms with a few spots to itchy rash covering the whole body, which can be very distressing, affecting sleep, school and work and causing scarring to the skin.
In children, complications of Chickenpox are rare, but include:
- Superimposed bacterial infection of the skin, which can be widespread
- Neurological complications such as encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain).
- very rarely-inflammation of the kidney and arthritis.
Adults who catch Chickenpox are more likely to have severe illness with complications, including:
Chickenpox in Pregnancy is a serious disease for the mother and especially the baby. Therefore, it is important to know before trying for pregnancy whether you have immunity to this illness and if not, vaccination may be appropriate to protect you.
There is no specific treatment for Chickenpox as most children will recover spontaneously. The mainstay of managing the infection includes pain medications, antihistamines and soothing skin lotions such as calamine. In severe infections, antiviral drugs can be used to modify the illness. It is important if you are working closely with children or in health care to check whether you have already had Chickenpox, as there is vaccination is available to protect you.
As the disease is very infectious, if you are vulnerable to severe infection or have never had Chickenpox, then vaccination should be considered.
Chickenpox Vaccine – £75 per dose, 2 doses
The Chickenpox vaccine has been used routinely in the childhood immunisation programme in the United States since 1995 and is safe and effective prevention against Chickenpox infection. Many other countries also routinely provide the vaccination in their immunisation schedules.
The vaccine is live containing weakened virus. Two doses of the vaccine provides 98% protection in children and 75% protection in adults against Chickenpox infection. In both groups, if breakthrough infection does occur, it is much milder and of a shorter duration than in those who have never been vaccinated.
The vaccine can be given to anyone over 12 months of age:
- to prevent development of Chickenpox infection in those who have never had it.
- to protect occupational groups, such as those working with children and health care workers who have never had Chickenpox infection.
- to prevent healthy susceptible contacts of immunocompromised patients from transmitting natural infection to them. For example, siblings of a leukaemic child, or a child whose parent is undergoing chemotherapy.
- to prevent development of Chickenpox infection in those who have never had the illness and have been in close contact with a person with Chickenpox. The vaccine must be given within 3 days to prevent infection from occurring.
|Age can be given||Method of Administration||Dosing Schedule||Interval between doses||Booster dose requirement|
|12 months onwards||Intramuscular injection to the thigh or deltoid muscle depending on age||2 doses||4-8 weeks||None|
Post Exposure Prevention
To prevent infection from occurring in those who have never had chicken pox and have been exposed to infection (post exposure prevention): 2 doses of Chickenpox vaccine is required.
The first dose must be given within 3 days of the exposure to prevent the disease from developing. The first dose can be given 3-5 days from exposure to modify the severity of the disease.
After 5 days from exposure, there is no evidence that the vaccine will change the course of the infection and therefore, is not beneficial. The second dose should be given after 4 to 8 weeks.
The vaccine cannot be given to the following groups:
- Anyone with suppressed or weakened immune system caused by diseases such as leukaemia, lymphoma, severe HIV infection or due to drugs such as oral steroids, cancer therapies.
- In the presence of a illness with a high temperature (above 38.5 degrees Celsius)
- If there is a previous history of severe allergic reaction to Chickenpox vaccine or to any of the ingredients in the vaccine (see FAQ section)
- Anyone with active Tuberculosis
- Anyone with a uncontrolled neurological disorders, such as epilepsy not responding to medications.
- Pregnant women
The Chickenpox vaccine cannot be given to pregnant women under any circumstances.
If a pregnant women is not immune to Chickenpox and encounters the disease, they must see their NHS healthcare provider as soon as possible to start immunoglobulin treatment (passive antibodies against Chickenpox given via injection).
Pregnancy must be avoided during the vaccination course and for a further 1 month after the second dose has been received.
The Chickenpox vaccine can be given to breast feeding mothers. Studies have shown that the virus is not transmitted in breast milk to the infant.
Common Side Effects
- Local reactions at the injection site-including pain, redness and swelling
- Chicken pox like rash-occurs in 10% of adults and 5% of children who receive the vaccine. The rash is either localised around the injection site or generalised. across the body. On average, there is usually around 5 spots.
- The vaccine virus can stay in the body for life and reactivate as shingles, but the risk of this occurring is substantially lower than with naturally occurring infection.
Risk of transmitting infection
There have been isolated cases where the vaccine virus has been transmitted from the vaccinated individual to non immune contacts. As a general rule, contact with any individual with normal immune system is not a concern as the vaccine virus is weakened and will easily be dealt with by the immune system. However, because of the potential serious complications of Chickenpox infection in certain groups, we advise that close contact is avoided for a period of 6 weeks after the administration of the first dose with the following individuals:
- Pregnant women who have never had Chickenpox infection.
- Newborn babies (those within 28 days of birth) of mothers who have never had Chickenpox infection
- Anyone with poor or suppressed immune system such as those receiving cancer treatments.
However, it is important to bear in mind that the risk of transmission has only occurred from those individuals who have developed the rash following vaccination and is extremely rare. This is opposed to the highly infectious nature of Chickenpox itself.
Interactions with Other Vaccines
Chickenpox can be safely given at the same time as:
- Diphtheria, tetanus, polio, pertussis vaccines
- Meningitis B vaccine
- All travel vaccines including yellow fever
Chickenpox and MMR vaccine Interactions
Chicken pox vaccine must be given either on the same day as the MMR vaccine or separated by interval of 4 weeks.
This is because the MMR vaccine causes an increased response to the Chickenpox vaccine, which means that breakthrough infection with Chickenpox is more likely if this interval is not respected. However, the data available shows that the breakthrough infection with Chickenpox in these cases tends to mild and not full blown severe Chickenpox infection. Where both vaccines have been given within 4 weeks of each other, it is advisable to consider a further dose of the vaccine given second.
So whether you would like to protect your child or yourself against chicken pox, visit your local CityDoc clinic today.
Frequently Asked Question
1) How safe is the Chickenpox vaccine?
There has been extensive clinical studies and also post marketing experience with the Chickenpox vaccine, which have not demonstrated any serious adverse effects with this vaccine. Additionally, it has been used routinely in the US since 1995 without any safety issues being identified.
The decision to vaccinate would be based on the assessment by the clinician during the consultation.
3) Why is the Chickenpox vaccine not part of the NHS childhood schedule?
The Joint Committee on Vaccination and Immunisation (JCVI), which advises the UK Government, has so far recommended that it would not be cost effective to introduce the Chickenpox vaccine into the routine UK schedule for the following reasons:
- it is not cost-effective in the short-term;
- an increase in the incidence of herpes zoster (shingles) cases as a result of childhood varicella vaccination is likely to occur;
- a potential increase in varicella (Chickenpox infection) among adults is also likely if there is low vaccine coverage;
- it is not guaranteed that varicella vaccination will protect against herpes zoster (shingles) in later life due to re-infection. With poor uptake levels, re-infection would be common. The protection against herpes zoster is a key factor in making varicella vaccination cost-effective and therefore re-infection would have an effect on the cost-effectiveness of vaccination (JCVI minutes 2009).
The concerns with regards to an increase in shingles incidence has not currently been demonstrated in countries where the varicella vaccine is routinely given. However, it is too early to comment on epidemiological trends in these countries and further data would need to be obtained to confirm or refute this point.
In the meantime, the vaccine is available privately for those who feel it would be beneficial to vaccinate against this illness and are not entitled to it under the NHS.
4) Is my child infectious after receiving the Chickenpox vaccine?
As stated earlier, there have been isolated cases of transmission of the vaccine virus to people who do not have immunity to Chickenpox. If the person is already immune (has had Chickenpox infection), then there is no risk of transmission.
This is very rare and Chickenpox infection, itself is very contagious. The clinician will discuss this with you in the consultation.
5) Does my child need to stay away from nursery/school following vaccination?
Generally they do not need to kept away as the risk of them transmitting the infection is very low. However, If they develop a Chickenpox rash, they may need to be kept away. The doctor will discuss this in detail with you during the consultation.
6) Can my child have the vaccine if they are unwell?
If your child has a fever, then we would not recommend the vaccine is administered until they are well.
With regards to minor illnesses without a fever, such as cold or cough, vaccination can proceed. However, the decision to vaccinate would be made by the doctor following consultation and assessment.
7) If I am pregnant and have had Chickenpox infection already. Is it OK for my child to be vaccinated?
The vaccine virus cannot be transmitted to and cause infection or complications in people who already have immunity. Therefore, if you know that you have definitely had the Chickenpox infection, then both yourself and your unborn baby are safe and your child can be administered the vaccine.
8) Is there is a risk to very young siblings from older children being given the vaccine.
If you have had Chickenpox infection yourself, you will pass this immunity onto your baby and there would be no concerns about transmission of the vaccine virus. If you have never had Chickenpox then your baby will not have any immunity. However, the risk of transmission is very rare and has only occurred in those vaccinated individuals hat have developed a Chickenpox like rash. The vaccine virus is weakened and is unlikely to cause any noticeable infection in babies.
The exception to this, is newborn babies, that is babies under 28 days of age, born to mothers who have never had Chickenpox, as they may be vulnerable to severe illness form the vaccinated individual.
9) Is two doses of the vaccine required?
Two doses of the vaccine are needed to provide full protection against the illness.
10) What is a significant exposure to Chickenpox and when can the vaccine be used to prevent infection?
A significant exposure to Chickenpox would be considered as the following:
- Chickenpox infection in household contact-sibling or child
- Chickenpox infection confirmed in the nursery or school, particularly if your child has been in contact with the infected person.
The disease is infectious from 1-2 days before the rash comes out an for 5 days after.
Therefore, if the exposure has been within 3 days (ideally 1st day or 2 of rash), then the vaccine can be given to prevent disease from occurring. If the exposure was more than 3 days ago, but less than 5 days, then the vaccine can still be used to reduce the severity of the illness. After 5 days, the vaccine has no effect on the disease.
12) I am not sure if my child has been exposed to Chickenpox; can they still be vaccinated?
The incubation period for Chickenpox is 3 weeks. The disease is also highly infectious. Therefore, it is possible that your child may already be exposed and be incubating the virus. The decision to be vaccinate would be made following a risk assessment during the consultation with the clinician. If it is decided to vaccinate, then you must report any rash so that it can be swabbed to see if the vaccine virus is responsible or if it is due to natural infection. If the latter, then further dose of the vaccine is not required.
13) If have received one dose of the vaccine and then become exposed to Chickenpox, do I still need the second dose?
In clinical trials, individuals between 12 months to 12 years of age who had received one dose of the Chickenpox vaccine and were then exposed to Chickenpox infection were either completely protected from Chickenpox or developed a milder form of the disease.
Therefore, it is likely that one dose of Chickenpox will provide significant protection against the disease and if exposure occurs, any breakthrough illness would be mild. It is reasonable to wait until the incubation period has elapsed to see if Chickenpox infection has occurred and if not, there is no harm in administering the second dose for full protection.