chicken

Varivax®

Varicella

Varivax® is used for primary vaccination of children from 12 months of age and adults to protect against varicella-zoster infection (chickenpox). The vaccine may prevent or reduce the severity of chickenpox disease if it is given within 3-5 days of exposure to someone with the disease.

Varilrix®

Varicella

Varilrix® is used for primary vaccination of infants from nine months of age, children and adults to protect against varicella-zoster infection (chickenpox). The vaccine may prevent or reduce the severity of chickenpox disease if it is given within 3-5 days of exposure to someone with the disease.

Varilrix® is back in stock and available to order from 3 March 2014.

Varicella

Common Name: 
Chickenpox
Parents & Caregivers
Introduction: 

Chickenpox, also known as varicella, is a highly infectious disease caused by the varicella zoster virus. After recovery from chickenpox the virus stays dormant (inactive) in the nerves near the spine. Years later the virus can become active again and cause herpes zoster which is also known as shingles.

The current New Zealand situation: 

Chickenpox is more commonly seen in children. Shingles usually affects adults 50 years of age or older and people of any age with an immune system weakness. In countries where chickenpox is common very few people avoid ever having the disease because more than 85% of people susceptible to chickenpox will become infected after exposure to the virus. Although rare some people get chickenpox more than once.

Symptoms: 

The early symptoms of chickenpox may include a mild fever, loss of appetite, headache and feeling tired, followed by the appearance of a red rash that becomes itchy blisters mostly on the trunk and face with some on the arms and legs. The blisters can occur in the eyes, mouth/throat, vagina and urinary tract. The blisters release liquid containing the virus and form crusts/scabs that fall off after 1-2 weeks.

How do you get it?: 

The virus can be transferred from person to person through droplets of saliva in the air from people coughing, sneezing or laughing. It can also be transferred by direct contact with the liquid from the rash blisters.

A person with chickenpox can pass the virus on for 1-2 days before they get the rash until after the rash blisters have dried up, which usually takes 5-7 days. It is possible for a person with shingles to pass the virus on to someone not immune to chickenpox but only by direct contact with the rash blisters.

What are the risks?: 

Complications of chickenpox include:

  • Difficulty drinking and eating.
  • Changes in skin colour after the crusts fall off that may last for months. Permanent scarring may also occur.
  • Around one in every 20 healthy children with chickenpox will develop a bacterial skin infection, usually from scratching, that needs to be treated with antibiotic medicine.
  • Bacterial skin infections can lead to bacterial infection in other parts of the body, including the blood (septicaemia).
  • Although rare chickenpox infection can cause inflammation of the central nervous system (cerebellar ataxia), joints (arthritis), bones (osteomyelitis), lungs (pneumonia), liver (hepatitis), blood vessels supplying the brain with blood (intracranial vasculitis), and brain (encephalitis).
  • Maternal chickenpox during pregnancy can infect the fetus. The highest risk period is during the first 20 weeks of pregnancy when up to two in 100 infants exposed to chickenpox before birth will be born with congenital varicella syndrome and may have skin scarring, eye, limb and brain abnormalities, developmental delay and a poor outcome.
  • Maternal chickenpox within five days before to two days after delivery can infect the newborn infant. Up to 30 in 100 newborns with chickenpox develop severe disease that can result in death.
Who is most at risk?: 

Chickenpox is usually less severe in healthy children than in adolescents and adults. Although most healthy children will only need relief from itching and to continue drinking, some will develop serious complications. Adolescents and adults are more likely to develop complications than children.

Those who catch the disease from another household member often have more severe chickenpox than the person they caught it from.

Treating the symptoms: 

Reducing pain, discomfort and itching associated with the blisters, preventing dehydration and skin infection and providing early antibiotic medicine when skin infection occurs are the main treatment measures for healthy children.

For healthy adolescents and adults, the use of antiviral medicine should be considered in addition to comfort measures. Antiviral medicine started within 24 hours of the rash appearing may reduce the severity of the disease.

Tips for managing chickenpox symptoms

  • Drink plenty of water.
  • Trim nails short and consider using mittens or clean socks, to decrease the risk of scratching, especially overnight.
  • Have a cool or lukewarm bath every 3-4 hours. Do not use soap. Try adding oatmeal, baking soda or moisturising bath lotion to the bath water. Pat dry, do not rub, after bathing.
  • Moisturise with non-irritating skin lotion. Calamine lotion is not recommended.
  • Dress in loose fitting clothing and change the bed linen daily.
  • When blisters in the mouth and throat affect drinking and eating, offer clear cool drinks and soft bland foods and avoid acidic drinks such as fruit juices.
  • Use paracetamol to relieve discomfort and pain.
  • If itching is severe, ask your doctor about anti-itching medicine in liquid or tablet form.
  • Aspirin or any medicine with an ingredient name including the words ‘salicylate’ or ‘salicytic acid’ MUST NOT be given to children with chickenpox because of the risk Reye’s Syndrome.
Preventing Disease Spread: 

Children with chickenpox are advised not to attend early childhood services, school or public places for at least one week from the appearance of the rash  until all the blisters are dry and crusted. Adults are advised not to attend work or public places for the same period of time.

Varilrix® and Varivax® are the two chickenpox vaccine brands available for private purchase through your nurse or doctor. Both contain live weakened varicella zoster virus. The combination measles, mumps, rubella and chickenpox vaccine is not available in New Zealand at this time.

Chickenpox vaccine can be given from nine months of age ideally before but also if necessary after exposure to the disease. Studies have shown that giving the vaccine to children 12 years or younger within 72-96 hours of exposure to chickenpox can prevent the disease developing or reduce the severity of the disease. The vaccine can also be given to older children and adults after exposure to chickenpox. However, a single dose after exposure in this age group may not prevent or reduce the severity of disease. Receiving the vaccine after exposure to the disease will not make the disease more severe at any age.

All new born newborn infants exposed to chickenpox around the time of delivery, hospitalised infants born before 28 weeks of pregnancy or with a birth weight less than 1000 grams, and children and adults with weakened immune systems and no reliable history of chickenpox should receive zoster immunoglobulin, a human blood product that provides protection against the disease, as soon as possible after and within 96 hours of exposure to the disease.

Pregnant women with no reliable history of chickenpox should have an urgent blood test to check for immunity after exposure to chickenpox. If the blood test suggests no immunity against chickenpox, they can receive zoster immunoglobulin within 96 hours of exposure, or wait for the onset of symptoms and begin antiviral medicine immediately.

Health Professionals
Causative organism: 

Varicella zoster virus is an alpha-herpesviridae virus in the herpes virus family. Humans are the only host.

The unique feature of the alpha-herpesviridae viruses is their ability to become latent in sensory ganglia during primary infection and reactivate at a later stage.

Clinical signs, symptoms and complications: 

Chickenpox is usually less severe in healthy children than in adolescents and adults. Although most healthy children will only need relief from itching and to continue drinking some will develop serious complications. Adolescents and adults are more likely to develop complications than children.

Children with eczema may have a slightly more severe rash, no additional treatment is recommended. Steroid creams should not be applied to the skin until the crusts have fallen off.

Infants less than one year of age, older adults and those with weakened immune systems are at high risk of serious complications. However, because more cases of chickenpox occur in healthy children than in those who have weakened immune systems the risk of healthy children developing serious complications is also higher.

Those who catch the disease from another family member often have more severe chickenpox than the person they caught it from.

It is possible but unusual for someone to have chickenpox without any symptoms.

Complications of chickenpox include:

  • Difficulty drinking and eating.
  • Changes in skin colour after the crusts fall off that may last for months. Permanent scarring may also occur.
  • Around one in every 20 children with chickenpox will develop a bacterial skin infection, usually group A beta-haemolytic streptococci, that needs to be treated with antibiotic medicine. Bacterial skin infections can cause bacterial infection in other parts of the body including the blood (septicaemia).
  • Chickenpox infection can also cause inflammation of the:
    • Central nervous system (cerebellar ataxia)
    • Joints (arthritis)
    • Bones (osteomyelitis)
    • Lungs (pneumonia)
    • Liver (hepatitis)
    • Blood vessels supplying the brain with blood (intracranial vasculitis), and
    • Brain (encephalitis)
  • Cerebellar ataxia is more commonly seen in children, usually developing a week after the rash appears. The child experiences uncoordinated movements that gradually improve over 1-2 weeks and resolve without any lasting impairment.
  • Pneumonia is more likely to occur as a complication in adults, particularly pregnant women during the last trimester of pregnancy.  Around one in 10 people with chickenpox related pneumonia need to be hospitalised.
  • Maternal chickenpox during pregnancy can infect the fetus. The highest risk period is during the first 20 weeks of pregnancy when up to two in 100 infants exposed to chickenpox before birth will be born with congenital varicella syndrome. Characteristics of congenital varicella syndrome include skin scarring, eye, limb and brain abnormalities, cataracts, developmental delay and early death.
  • Maternal chickenpox within five days before and two days after delivery can infect the newly born infants. Up to 30 in 100 new-borns with chickenpox develop severe disease that can result in death.
  • Reye’s Syndrome can occur after a viral infection in children, including chickenpox. It is more likely to occur when children are given aspirin or a medicine with an ingredient name including the words salicylate or salicytic acid. These medicines MUST NOT be given to children with chickenpox or any other viral illness.
  • Herpes zoster (shingles) is due to reactivation of latent varicella virus infection. This consists of a dermatomally distributed vesicular rash. The majority of cases of zoster occur in adults over 50 years of age and in immune-suppressed individuals. Ophthalmic herpes zoster may cause permanent loss of vision.
Method of transmission: 

Chickenpox can occur all year round but is most common during winter and spring.

The virus can be transferred from person to person through droplets of saliva in the air from people coughing, sneezing or laughing. It can also be transferred by direct contact with the liquid from the rash blisters.

A person with chickenpox can pass the virus on for 1-2 days before they get the rash until after the rash blisters have dried up, which usually takes 5-7 days. It is possible for a person with shingles to pass the virus on to a person not immune to chickenpox but only by direct contact with the rash blisters.

In countries where chickenpox is common few people avoid ever having the disease because more than 85% of people susceptible to chickenpox will become infected after exposure to the virus.

Public health significance: 

An estimated 90% of all children are infected with varicella before they reach adolescence.

Adults, adolescents and those with immune-suppression are more likely to experience serious disease.

Varicella is highly infectious, from up to two days before appearance of the rash until blisters have crusted (usually about 5-7 days after the appearance of the rash). If one person has varicella, about 85% of their close contacts will get it too, unless they have had the disease or the relevant vaccine.

The risks of severe complications from super infection with group A beta-haemolytic streptococci, (including cellulitis, streptococcal toxic shock syndrome, necrotising fasciitis and post-infectious glomerulonephritis), is of concern due to the continued resurgence of highly virulent strains of Streptococcus pyogenes since the early 1980s, particularly in countries with developed economies.

Babies born to women who contract varicella in the first two trimesters of pregnancy have a 0.4-2% chance of congenital varicella syndrome.

Babies whose mother has onset of chicken pox from five days before until two days after delivery have a 17-30% of developing severe disease.

The elderly and the immune-compromised may develop herpes zoster due to reactivation of latent varicella virus. There is a 50% chance of developing shingles between the ages of 50 and 65 in the USA.

New Zealand epidemiology: 

In New Zealand it is expected that 90 percent of children would have had varicella infection before adolescence, with peak incidence in the five to nine years age group. With higher participation rates in preschool education, a greater proportion of infections may now be occurring in preschool aged children.

Only four percent of hospitalisations involved people with an underlying disease associated with immune suppression. The rate of hospital discharges for the zero to four and five to nine years age groups was higher compared with older age groups because the disease is most common in childhood. However, adults, adolescents and infants are more likely to suffer severe illness or the complications of varicella.

Based on overseas rates, it is estimated that up to one case of congenital varicella syndrome may be expected in New Zealand each year, although few have been reported.

Mortality data are available for the period 1980 to 2002. Nine deaths were attributed to varicella over the 14-year period 1980 to 1993, of which four occurred in children, two in infants and three in adolescents or adults. None of the cases who died had a contributory cause of death recorded. From 1994 to 2002 there were also nine deaths associated with varicella, two were children aged five to nine years, four were adults aged 30 to 64 years and three were adults over the age of 65 years.

Larger series from other developed temperate climate countries suggest that up to 10 percent of varicella deaths may involve individuals with immune suppression.

In summary, in a typical year New Zealand is estimated to experience approximately 50,000 varicella infections, of which 150–200 result in hospitalisation, one to two cases result in residual long term disability or death, and 0.5–1 cases result in severe congenital varicella syndrome. About two-thirds of this burden is borne by otherwise healthy children, and less than one-tenth by children with a disease associated with immune suppression.

Prevention: 

Children with chickenpox are advised not to attend early childhood services, school or public places for at least one week from the appearance of the rash  until all the blisters are dry and crusted. Adults are advised not to attend work or public places for the same period of time.

High risk contacts should also be excluded from early childhood services and school during the duration of an outbreak.

Varilrix® and Varivax® are the two chickenpox vaccine brands available for private purchase through your nurse or doctor. Both contain live weakened Oka strain varicella zoster virus. The combination measles, mumps, rubella and chickenpox vaccine is not available in New Zealand at this time.

The herpes zoster vaccine Zostavax® is recommended for adults 50 years of age and over.

Chickenpox vaccine can be given from nine months of age ideally before but also if necessary after exposure to the disease. Studies have shown that giving the vaccine to children 12 years or younger within 72-96 hours of exposure to chickenpox can prevent the disease developing or reduce the severity of the disease. The vaccine can also be given to older children and adults after exposure to chickenpox. However, a single dose after exposure in this age group may not prevent or reduce the severity of disease. Receiving the vaccine after exposure to the disease will not make the disease more severe at any age.

All new born newborn infants exposed to chickenpox around the time of delivery, hospitalised infants born before 28 weeks of pregnancy or with a birth weight less than 1000 grams, and children and adults with weakened immune systems and no reliable history of chickenpox should receive zoster immunoglobulin, a human blood product that provides protection against the disease, as soon as possible after and within 96 hours of exposure to the disease.

Pregnant women with no reliable history of chickenpox should have an urgent blood test to check for immunity after exposure to chickenpox. If the blood test suggests no immunity against chickenpox, they can receive zoster immunoglobulin within 96 hours of exposure, or wait for the onset of symptoms and begin antiviral medicine immediately.

Contact can be defined as:

  • Household contact – individuals living in the same house are very likely to be infected if susceptible.
  • Play mate contact – defined as more than one hour of play indoors with an infected individual.
  • Newborn infant contact – occurs when the mother of a newborn infant develops chicken pox, but not shingles, from one week before to one week after delivery.

Post-exposure prophylaxis with Zoster Immune Globulin (ZIG)

The recommended ZIG concentration is 100 U/mL with the volume of dose administered determined by the age of the recipient:

  • Adults - 6mL
  • Children aged 6-12 years - 4mL
  • Children aged 0-5 years - 2mL

Human normal IG is indicated when ZIG is unavailable

Treatment: 

Reducing pain, discomfort and itching associated with the blisters, preventing dehydration and skin infection and providing early antibiotic medicine when skin infection occurs are the main treatment measures for healthy children.

For healthy adolescents and adults, the use of antiviral medicine should be considered in addition to comfort measures. Antiviral medicine started within 24 hours of the rash appearing may reduce the severity of the disease.

Tips for managing chickenpox symptoms

  • Drink plenty of water.
  • Trim nails short and consider using mittens or clean socks, to decrease the risk of scratching, especially overnight.
  • Have a cool or lukewarm bath every 3-4 hours. Do not use soap. Try adding oatmeal, baking soda or moisturising bath lotion to the bath water. Pat dry, do not rub, after bathing.
  • Moisturise with non-irritating skin lotion. Calamine lotion is not recommended.
  • Dress in loose fitting clothing and change the bed linen daily.
  • When blisters in the mouth and throat affect drinking and eating, offer clear cool drinks and soft bland foods and avoid acidic drinks such as fruit juices.
  • Use paracetamol to relieve discomfort and pain.
  • If itching is severe, ask your doctor about anti-itching medicine in liquid or tablet form.
  • Aspirin or any medicine with an ingredient name including the words ‘salicylate’ or ‘salicytic acid’ MUST NOT be given to children with chickenpox because of the risk Reye’s Syndrome.
Disease Effects vs Vaccine Side Effects (Table)
Disease Description: 

A highly contagious viral illness causing fever and a rash that becomes itchy blisters.

Years later the virus can become active again and cause herpes zoster which is also known as shingles.

Effects of disease: 
Difficulty drinking and eating.
Changes in skin colour and/or permanent scarring.
Around 1 in 20 children develop a bacterial skin infection that needs to be treated with antibiotic medicine.
Bacterial skin infections can cause bacterial infection in other parts of the body including the blood (septicaemia).
Around 1 in 4,000 children develop inflammation of the central nervous system causing uncoordinated movements (cerebellar ataxia) that gradually improve.
Pneumonia is more likely to occur as a complication in adults, particularly pregnant women during the last trimester of pregnancy.
Inflammation of the joints (arthritis), bone (osteomyelitis), liver (hepatitis) and blood vessels supplying the brain with blood (intracranial vasculitis).
Around 4 in 10,000 develop brain inflammation (encephalitis). Infants less than one year of age and adults have the highest risk.
In developed countries: Between 2-6 in 100,000 require hospitalisation Overall death rate of 2-4 in 100,000
Maternal chickenpox during pregnancy can infect the fetus: Up to 2 in 100 infants exposed to the disease during the first 20 weeks of pregnancy will be born with congenital varicella syndrome and may have skin scarring, eye, limb and brain abnormalities, developmental delay and a poor outcome.
Maternal chickenpox within five days before and two days after delivery can infect the newly born infants: Up to 30 in 100 new-borns with chickenpox develop severe disease that can result in death.
Reye’s Syndrome may occur in children if aspirin (salicylate or salicytic acid) is given after a viral infection in children, including chickenpox.
Shingles, in later life causing severe pain which can be prolonged and disabling.
Common side effects of vaccine: 
Around 1-2 in 10 experience soreness/pain, redness and/or swelling around the injection site.
Around 5 in 100 experience a fever over 37.5°C.
Around 5 in 100 develop a vaccine rash with few spots compared with wild-type disease within 6-43 days of immunisation.
Uncommon side effects of vaccine: 
Headache and tiredness.
Fever over 39°C.
Herpes zoster (shingles) later in life.*
*Available information suggests that shingles may occur less frequently after chickenpox immunisation than after wild-type disease.
Rare/very rare side effects of vaccine: 
Anaphylaxis (severe allergic reaction), around 28 cases in 1,410,000 doses.
Transfer of the vaccine virus from a vaccine rash to another person 6 cases in more than 48 million doses.
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