What is Chickenpox?

Chickenpox in childhood results in £24 million in lost income and productivity every year in the UK, although the true cost is likely to be higher, according to new research by the London School of Economics (LSE).

The direct medical costs of Chickenpox have been widely reported, but less is known about the indirect societal costs of Chickenpox in the UK. The researchers set out to estimate the indirect costs, in terms of productivity loss, of Chickenpox among children aged 15 years and younger in the UK, as measured by the number of working days lost caring for a child with Chickenpox, and the estimated cost to society of each working day’s output lost.

Among respondents, working women (72%; 163/226) were significantly more likely to provide care for sick children compared to employed men (55%; 56/102). There was also a large gender difference between unemployed women (32%;104/330) and men (18%; 22/124).

The researchers calculated that the daily costs of lost productivity were around £170, and that there were around 200,000 GP consultations per year for Chickenpox. They used the figures to estimate that the total cost of annual productivity losses due to Chickenpox in the UK is around £24 million.

What is Chickenpox?

The medical name for Chickenpox is varicella; it is caused by the varicella-zoster (VZ) virus and is a highly infectious disease. This means it is easy to catch from someone who already has Chickenpox. Once you have had Chickenpox, your body is able to protect you from catching it again and it is likely that you will stay immune for life. Although it is possible to get Chickenpox again, usually if your first infection was very mild, this is very rare.

Chickenpox is not a notifiable disease in England and Wales and laboratory confirmation of cases of Chickenpox is rarely sought as the diagnosis can, in general, be reliably made on clinical grounds by a GP.

How common is Chickenpox?

Chickenpox is a common childhood infection. Children under 10 years are most likely to catch Chickenpox, but you can be affected at any age. This childhood illness is usually most common as winter ends and spring begins, with the months between March and May usually given as the times when peaks occur in the UK.

During 2020 and 2021, the majority of the Chickenpox season occurred during lockdowns or when some form of social distancing rules were in force, meaning that it has been difficult for the illness to spread among children, resulting in a large number of children across the UK who are not yet immune to the Chickenpox virus.

The common concept of immunity to Chickenpox once a child has had it is true, and so at present, more children across the UK are at risk of picking the virus up after being kept away from it for the last two years during COVID.

Since Chickenpox is so common in childhood, 90% of adults raised in the UK are immune. However, this means that there is still around 10% of adults who may be susceptible to getting the virus.

How can you catch Chickenpox?

The virus spreads easily from people with Chickenpox to others who have never had the disease or who have never been vaccinated. If one person has it, up to 90% of the people close to that person who are not immune will also become infected. The virus spreads mainly through close contact with someone who has Chickenpox; it is spread easily through the air when you cough or sneeze or if you touch infected surfaces or the Chickenpox blisters. So if you have not had Chickenpox before and someone in your household gets it, it is very likely that you will catch it too.

What is the incubation period for Chickenpox?

An incubation period is the time from initial exposure to a pathogen (an organism causing disease to its host), until the first sign of symptoms. The infectious period is the time during which a person is contagious and able to transmit an infection to other people.

The average incubation period for Chickenpox is 14 to 16 days after exposure to a varicella or a herpes zoster rash, with a range of 10 to 21 days.

Chickenpox is contagious from one to two days before the rash appears until all of the blisters have scabbed over, which takes about five days. Because Chickenpox is highly contagious, you should try to prevent spreading it by avoiding contact with others, particularly those at higher risk of complications, such as pregnant women and people with weakened immune systems.

Vaccinated people who get Chickenpox may develop lesions that do not crust. These people are considered contagious until no new lesions have appeared for 24 hours.

Signs and symptoms of Chickenpox

Some people start to feel unwell before the Chickenpox rash begins. You might have symptoms such as:

• A raised temperature (fever).
• A headache.
• A sore throat.
• Loss of appetite, although this is more likely in teenagers and adults.

The rash that you get with Chickenpox first develops on the face, scalp and chest. The rash has flat or slightly raised red spots, which rapidly progress to fluid-filled blisters. The spots appear in patches and may spread to the arms and legs. You may also get them in the mouth, nose and genitals.

When the blisters appear they can be extremely itchy and will usually crust over within a few days, forming scabs, and they can take around two weeks to heal completely. Some children may have only a few blistered spots, but others will have spots all over their bodies.

Chickenpox symptoms will vary from person to person and it is possible to have very few symptoms, or to not even notice that you have had Chickenpox at all in very mild cases. However, the symptoms tend to be worse in adults and they are also more likely to develop complications – more about these below.

How is Chickenpox Diagnosed?

The Chickenpox rash is such a distinctive rash that you will probably be able to tell that it is Chickenpox, particularly if you have recently been in close contact with someone who has developed Chickenpox.

If you are unsure whether the symptoms could be due to something else though, contact your GP; you should also contact your GP if you are feeling particularly unwell. If you are pregnant, have a newborn baby, or you have a weakened immune system and have been exposed to Chickenpox, you should always contact your GP.

If you do need to contact your GP for an appointment, you should make them aware that you suspect Chickenpox because it is such a contagious disease. They will want to make sure that you don’t pass the infection on to anyone who is at a higher than normal risk of complications from Chickenpox.

How dangerous is Chickenpox?

Complications of Chickenpox are rare. If you are generally healthy, Chickenpox is usually a mild infection and it is unlikely that you will have any serious problems. Once you have recovered from Chickenpox, the virus stays hidden in your body. This doesn’t usually cause any symptoms, but at any time later in your life, the virus can be reactivated, causing Shingles (more about Shingles later).

Sometimes the Chickenpox spots/blisters can get infected with bacteria which probably occurs because the patient scratches the rash – this is more common in children. Chickenpox spots/blisters can sometimes leave scars, especially if they have become infected. The signs of a bacterial infection include a high temperature (fever) and redness and pain around the Chickenpox spots/blisters. If you or your child develop these symptoms you should seek urgent medical help: call your GP or NHS 111.

Young children can also be at risk of becoming dehydrated with Chickenpox. The signs to look out for include needing to go to the toilet less than usual, feeling very tired and having cold fingers and toes.

Some of the more serious complications of Chickenpox can include:

• Lung infection (pneumonia) which can cause a persistent cough, breathing difficulties and chest pain.
• Inflammation of the liver (hepatitis).
• Infection of the brain (encephalitis).
• Scarring, if the rash is scratched.

Signs of these more serious problems can include:

• A lack of energy.
• Drowsiness.
• Confusion.
• Seizures (fits).
• Vomiting.
• Severe headaches.
• A stiff neck.
• Behavioural changes.
• Problems with walking, balance or speech (ataxia).

You are more likely to get pneumonia if you smoke or are pregnant. Problems with contracting Chickenpox during pregnancy include the infection spreading to the unborn baby.

You cannot get Shingles from someone with Chickenpox. When people get Chickenpox, the virus remains in the body and it can be reactivated later causing Shingles if someone’s immune system is lowered. This can be because of stress, certain medical conditions, or treatments such as chemotherapy.

The first signs of Shingles can be a tingling or painful feeling in an area of skin and a headache or feeling generally unwell. A rash will appear a few days later. Usually, you get the Shingles rash on your chest and tummy, but it can appear anywhere on your body including on your face, eyes and genitals. The rash appears as blotches on your skin, on one side of your body only. A rash on both the left and right of your body is unlikely to be Shingles. It can take up to 4 weeks for the rash to heal and your skin can be painful for weeks after the rash has gone, but it usually gets better over time.

You cannot spread Shingles to others; however, people who have not had Chickenpox before could catch Chickenpox from you because Shingles is caused by the Chickenpox virus. If you suspect that you have developed Shingles, call your GP or NHS 111 for advice.

What Treatment is Available for Chickenpox?

Until the spots/blisters have become scabs, it is recommended that anyone with Chickenpox should stay at home; this usually takes five days. During this time anyone with the illness should drink plenty of fluids to stay hydrated – you could try ice lollies if your child isn’t drinking. A diet of soft, cold foods is best if Chickenpox sores develop in the mouth.

Take age-related paracetamol to assist with any pain and discomfort and avoid using ibuprofen for Chickenpox unless advised to do so by your doctor as it can cause adverse skin reactions during Chickenpox. You also should not give aspirin to children under 16.

Don’t scratch the Chickenpox rash, as it can cause infection or permanent scarring. If your child can’t stop scratching, keep their fingernails short and put gloves or socks on their hands, especially at night. You can also ask your pharmacist about cooling creams or gels to help to relieve the itching. Keep the rash clean and dry to reduce the risk of infection and wear loose-fitting clothing to avoid chafing. If an infection develops, your GP may prescribe antibiotics.

How to Avoid Getting Chickenpox

The best way to avoid getting Chickenpox is to avoid contact with anyone who has it, as it is such a contagious virus. To prevent spreading the infection, parents should keep children away from nursery or school until all their spots have crusted over.

If your child has Chickenpox, try to keep them away from public areas to avoid contact with people who may not have had it, especially people who are at risk of serious problems, such as newborn babies, pregnant women and anyone with a weakened immune system such as people having cancer treatment or taking steroid tablets.

For anyone about to go on holiday, if you or your child have Chickenpox, you may not be allowed to fly until six days after the last spot has appeared. It is best to check the policy of your airline first and to inform the airline as soon as Chickenpox is diagnosed.

It is also important to let your travel insurer know if you or your child has Chickenpox, as you will need to make sure that you will be covered if you have to delay or cancel your holiday, or if you need to extend your stay until your child is well enough to fly home.

Many of the preventative measures taken during the COVID pandemic can also help to prevent the spread of Chickenpox, for example:

• Wiping any objects or surfaces with a sterilising solution.
• Making sure that any infected clothing or bedding is washed regularly.
• Washing hands thoroughly.
• Staying at home whilst infectious.

Is there a vaccination for Chickenpox?

There is a Chickenpox vaccine that is used to protect people who are most at risk of a serious Chickenpox infection or of passing the infection on to someone who is at risk. The Chickenpox vaccine is not part of the NHS childhood vaccination programme. This is because there is a worry that introducing a Chickenpox vaccination for all children could increase the risk of Chickenpox and Shingles in adults.

Chickenpox vaccinations are provided free on the NHS where there is a clinical need, such as for healthy people who are not immune to Chickenpox and are in close contact with someone who has a weakened immune system. The vaccine is not given to people with a weakened immune system as it contains a small amount of the live virus that causes Chickenpox. The recommended two doses of the vaccine are estimated to offer 98% protection from Chickenpox in children and 75% protection in adolescents and adults, so it may be possible to develop the infection after vaccination.

The vaccine is usually given as two separate injections into the upper arm, 4 to 8 weeks apart. Whilst vaccinations shouldn’t cause too much discomfort, the injected area can become swollen and red. You may also develop a fever, that is a temperature over 37.5°C, so it is a good idea to check your temperature regularly with a thermometer and use paracetamol if needed.

Following the vaccination, if you are in any doubt about your health, trust your instincts and get advice urgently by contacting your GP or by calling the NHS on 111, or call an ambulance in the case of an emergency. If you find out that you are pregnant within a month of having the Chickenpox vaccine, it is best to contact your GP for advice.

On rare occasions, people who have received the Chickenpox vaccine can transmit the infection to others. If you are very likely to come into contact with pregnant women who haven’t had Chickenpox, newborn babies of mothers who haven’t had Chickenpox, those with a weakened immune system or who are at risk of serious illness if they have Chickenpox, you should avoid any such contact during the period between vaccinations and for six weeks after the second dose. This is particularly important if you develop a rash within six weeks of the first or second dose. Should this occur, contact must be avoided until the rash has completely disappeared. This is because more vulnerable people can develop serious complications if they catch Chickenpox.

A vaccine to prevent Shingles is available on the NHS to people in their 70s, but is not available to anyone aged 80 or over because it seems to be less effective in this age group.

Final thoughts

Children who are developing Chickenpox are infectious around two days before the spots start to break out, which means that they can transmit the virus and Chickenpox can spread through schools like wildfire. So, if your child develops Chickenpox it means that they will need to stay at home from school until they are completely better; that is, until every blister has scabbed over.

Also, don’t be tempted to give a so-called “Chickenpox party” – a get-together where children who haven’t had Chickenpox are invited to play with a child who has Chickenpox. Public Health England (PHE) advises against Chickenpox parties or deliberately exposing your child to Chickenpox because if they do develop Chickenpox, they could then transmit it to any vulnerable people that they know, such as pregnant women and their unborn babies.