Chickenpox (varicella zoster) was once a childhood rite of passage; there was nothing to be feared but definitely not the best fun you could have during the spring holidays.

Since the varicella vaccine has been included on the childhood vaccination program of many countries, chickenpox is now considered to be a disease to be avoided at all costs – except in the United Kingdom.

What is chickenpox (also known as chicken pox) and why does the UK prefer to have natural rather than artificial immunity to this childhood disease?

Related reading: 12 Educated Doctors Speaking Out About Vaccination.

Why doesn’t the UK vaccinate for chickenpox?

The chickenpox vaccine is not part of the UK National Health Service childhood vaccination program.

The main reason for not vaccinating against this common childhood disease in the UK is to provide natural immunity to people at an early age, so they don’t contract the virus when they are older, which increases the risk of complications.

In the UK, chickenpox is extremely common during childhood. As a result, over 90% of adults have natural immunity to the virus. Most vaccination programs aim to have this percentage of the population vaccinated for varicella.

Who can get the chickenpox vaccine?

In the NHS, the varicella vaccine is offered free of charge if there is a clinical need. For example, it’s offered to adults who live in close contact with clinically vulnerable people who could become seriously ill if they were to develop chickenpox, such as those with a weakened immune system. For instance, if you were receiving chemotherapy treatment and lived with preschool age children, the eligible children would be offered the varicella vaccination, in an attempt to lessen the chances of them contracting the virus and passing it on.

It may also be offered to other adults without evidence of immunity, whose jobs put them at a higher chance of catching the varicella infection – for example healthcare professionals, teachers, nursery nurses or lab technicians, who might come into contact with people infected with the virus.

The chickenpox vaccine is not given to those with weakened immune systems, as the vaccine contains a small dose of varicella virus.

Chickenpox vaccine: NHS

The NHS website states:

‘There’s a worry that introducing chickenpox vaccination for all children could increase the risk of chickenpox and shingles in adults.

‘While chickenpox during childhood is unpleasant, the vast majority of children recover quickly and easily.

‘If a childhood chickenpox vaccination programme was introduced, people would not catch chickenpox as children because the infection would no longer circulate in areas where the majority of children had been vaccinated’.

Those who are exposed to chickenpox and contract the virus as adults are more likely to develop a more severe infection or a secondary complication. In pregnancy, there is an added risk of disease complications harming the baby.

What are the dangers of the chickenpox vaccine?

One of the major concerns about introducing the chickenpox vaccine into routine immunisation practices is that it could increase the risk of chickenpox and shingles in adults. It might also increase the risk of a secondary complication or increase incidences of chickenpox in pregnancy, when immunity is lowered.

Chickenpox in pregnancy can cause harm to your baby.

Once you’ve had chickenpox, the varicella zoster virus remains dormant in the body, and can become reactivated at a later stage, causing shingles (herpes zoster).

If you have already had chickenpox yourself and you are exposed to the virus as an adult – for example, while caring for your children when they have chickenpox – your body will naturally increase your immunity to shingles.

If we routinely immunise against varicella disease, as a population we lose this natural boosting of immunity to shingles, reducing shingles immunity in adults and therefore increasing cases of shingles in adulthood.

Contracting chickenpox as an adult often results in more severe illness at the primary infection and risks of complications increase with age.

What is shingles?

Shingles (also known as herpes zoster) is a painful condition caused by the same virus as chickenpox. In about 10-20% of cases, it is caused by a reactivation of the varicella zoster virus. The reasons for this reactivation are unclear, but it can be brought on by stress.

Herpes zoster causes a rash that turns into shingles blisters, which can appear anywhere over the entire body but more commonly on the chest and body. It will occur only on one side and rarely crosses the mid-line of the body. Anyone can have shingles, but the virus is more common in people over 50 years old or in those with a weakened immune system.

Symptoms of shingles include:

Headache
Sensitivity to light
A general feeling of being unwell
Itchy, tingling and painful rash
Shingles blisters, which develop in clusters over 3-5 days and then dry up and heal over
Permanent scarring or discolouration of the skin from the rash (in some cases).

People with active herpes zoster rash or blisters can transmit varicella zoster virus, causing chickenpox in those who have never had it or who have not received a varicella vaccination. Once the chickenpox is resolved, these people are then susceptible to shingles.

If you believe you have shingles speak to a healthcare provider as soon as possible and ask for advice.

For more information on the condition read our article Shingles – What Is Shingles?

Chickenpox vaccines available in other countries

In many countries around the globe where varicella vaccination is routine, it has proved to be very effective (around 90%) in preventing chickenpox.

The United States, Australia, Japan, Canada and some European countries have opted for routine chickenpox vaccination as part of their childhood immunisation programme.

As of early 2021, 44 countries had introduced universal chickenpox vaccination for infants.

Chickenpox vaccine

The varicella vaccination is live, meaning that it is a varicella-containing vaccine. The vaccine contains a weakened version of the varicella zoster virus, which stimulates the immune system to produce antibodies to protect those vaccinated.

There are two varicella vaccines that are licensed for use in the UK:

Varivax – for individuals 12 months and older
Proquad, which is a combination vaccine containing measles, mumps, rubella and varicella (also known as MMRV vaccine). Proquad is licensed for children from 12 months of age up to 12 years of age.

The varicella vaccine is not recommended for children younger than 12 months.

The varicella vaccine is usually given as 2 separate injections in the upper arm, 4-6 weeks apart. Schedules for vaccinations will differ from country to country; some countries have opted for a programme with just one dose of the varicella vaccine.

A single dose of varicella vaccine will reduce the severity of the disease but individuals are still prone to breakthrough disease or infections. Two doses however, will reduce the incidence as well as the severity.

The U.S Centers for Disease Control And Prevention recommend two doses, which protect around 98% of the population from developing chickenpox. In most cases, two doses will protect individuals for life.

Chickenpox vaccine for adults

The varicella vaccine can be given after childhood; however, its effectiveness is reduced. It is estimated that 75% of vaccinated adults will develop immunity to varicella disease.

What is chickenpox?

Chickenpox is caused by the varicella zoster virus. Chickenpox can be unpleasant but generally causes only mild illness. Most healthy people who contract the virus will recover fully without needing any special treatment.

The varicella zoster virus is highly contagious and outbreaks tend to occur in winter and spring.

Symptoms of chickenpox include:

Low grade fever (37-38 degrees Celsius)
Feeling low and lethargic
Small blisters, surrounded by irregularly-shaped patches of inflamed skin. These first appear on the torso and then spread to head and limbs. The rash can be mild to very profuse.

It’s important to note that people who have been vaccinated against chickenpox often have atypical symptoms of chickenpox. Spots might not appear on the torso first, and can be very mild in appearance.

What causes chickenpox to spread?

Once you have been exposed to chickenpox, and if you have been infected, it takes around 14 days for the rash to appear. This is called the incubation period.

The virus is highly contagious and can be passed on by airborne droplets from the mouth or nose (via sneezing or coughing). The fluid in the blisters also contains the virus and touching them can be a means of passing on the infection.

The contagion period usually starts 1-3 days before the rash appears and continues until the blisters form scabs, which happens about 5-7 days after the rash first appears.

Is chickenpox dangerous?

Complications from chickenpox can occur, but they are rare in healthy children.

Those who are at risk for complications include:

Babies under 4 weeks old (one of the reasons why a newborn/mother hybernation period or babymoon is beneficial)
Pregnant women who have no immunity to varicella, due to their immune systems being lowered
Anyone over the age of 15
Anyone whose immune system is weakened, due to illness or medication, such as people with leukaemia, cancer or HIV/AIDS, those taking immunosuppressive medications and people with long-term use of steroids.

Serious complications from chickenpox include:

Cellulitis: bacterial infection of the skin and tissues, which can lead to sepsis (infection of the bloodstream)
Pneumonia: infection and inflammation of the lungs
Encephalitis and cerebellar ataxia: inflammation of the brain which can affect muscle control (neurological complications are believed to be around 1-3 cases in 10,000)
Bleeding disorders: rare but potentially fatal.

According to the NHS, around 5-14% of adults who contract chickenpox experience lung problems, including pneumonia. Smokers have a higher risk. The vast majority, however, will make a full recovery from chickenpox.

Chickenpox during pregnancy

For those who contract chickenpox during pregnancy (about 3 in every 1,000 pregnancies), the risk of complications for the baby is, fortunately, very low but it can occur. The NHS states that if you are infected with chickenpox during the first 28 weeks of your pregnancy, your unborn baby could develop a rare condition known as fetal varicella syndrome (FVS).

The risk of FVS in the first 12 weeks of pregnancy is less than 1%.
Between weeks 13 and 20, the risk is 2%.
From weeks 20 to 28, the risk is believed to be much lower than 1%.

How do I treat chickenpox?

Antiviral medications can be prescribed by health care personnel for adults and teens who are at risk for more severe symptoms of chickenpox. This treatment is rarely given to otherwise healthy children.

The majority of people will experience a mild case of chickenpox. Treatment is aimed at relieving the discomfort of symptoms, rather than treating the virus.

Those with chickenpox should:

Have bed rest
Keep up fluids, especially if fever is present
Keep nails short, to avoid scratching blisters
Wear loose, light clothing, to avoid irritating the rash, and avoid heat and humidity
Take warm, but not hot, baths with baking soda or oatmeal added, to relieve itchiness
Use creams and lotions, which help soothe and reduce itching.

Although fever is a common part of chickenpox, temperatures are usually mild (around 37-38 degrees). It’s often recommended to leave fever alone, unless a child is very distressed.

For more information, see our article Fever Phobia – What Is The Best Way To Treat A Fever?

Very important medication information

Paracetamol is the preferred medication for treating symptoms of chickenpox.

Never give aspirin or ibuprofen to someone who has, or might have, chickenpox.

Aspirin has been associated with a serious illness called Reye syndrome, which causes swelling in the liver and brain
Ibuprofen is an anti-inflammatory medication, often given for fever pain, and has been linked to severe secondary infections in children with chickenpox.

Chickenpox is usually a mild disease, with symptoms that last for 1-2 weeks. Rest and treatment to relieve symptoms is the recommended course of action, unless the infected person is at risk for severe complications.

This article was written for informational purposes only. We do not advise for or against vaccination. What we advise is that parents do research and make their own decisions. Be sure to seek advice from your healthcare provider if you have any concerns about your child or other family member.