Varicella (chickenpox)

What

Varicella is a highly contagious infection caused by varicella-zoster virus. Primary infection with varicella-zoster virus causes varicella (chickenpox).

Who

Varicella-containing vaccine is recommended for:

• children aged ≥12 months to <14 years
• adolescents aged ≥14 years and adults who are non-immune, particularly
  • healthcare workers
  • childhood educators and carers
  • people who work in long-term care facilities

How

Varicella-containing vaccine is recommended for children at 18 months of age as MMRV (measles-mumps-rubella-varicella) vaccine.

All adolescents ≥14 years of age and adults should have either:

• documented evidence of 2 doses of varicella-containing vaccine given at least 4 weeks apart, or
• a history of varicella infection

Non-immune people ≥14 years of age can receive monovalent varicella vaccine. MMRV is not recommended in this age group.

Why

Varicella is more severe in adults, particularly in pregnant women and people who are immunocompromised.

Varicella vaccines available in Australia

The Therapeutic Goods Administration website provides product information for each vaccine.

See also Vaccine information and Variations from product information for more details.

Dose and route

The dose of all varicella-containing vaccines is 0.5 mL given by subcutaneous or intramuscular injection.

Co-administration with other vaccines

People can receive varicella or MMRV vaccine at the same time as other live attenuated parenteral vaccines or other inactivated vaccines,¹⁹ using separate syringes and injection sites. If a person does not receive varicella or MMRV vaccine at the same time as other live attenuated parenteral vaccines, wait at least 4 weeks between vaccinations.^20,21

If a person receives MMR (measles-mumps-rubella) vaccine at the same time as monovalent varicella vaccine, use separate syringes and injection sites. Do not mix MMR vaccine and monovalent varicella vaccine together before injection.

Interchangeability of varicella-containing vaccines

The 2 brands of varicella vaccine are interchangeable, so the 2nd varicella vaccine dose does not have to be the same brand as the 1st.

The same principle applies to the 2 MMRV vaccines,¹⁹ although they are not recommended in a 2-dose schedule.

Contraindications

Anaphylaxis to vaccine components

Varicella-containing vaccines are contraindicated in people who have had:

• anaphylaxis after a previous dose of any varicella-containing vaccine
• anaphylaxis after any component of a varicella-containing vaccine 

Women who are pregnant or breastfeeding

Varicella-containing vaccines are contraindicated in pregnant women. 

Vaccinated women should avoid pregnancy for 28 days after vaccination.¹⁵ This is because of the theoretical risk of transmitting the varicella component of the vaccine to a susceptible fetus. However, there are no reports of vaccine-induced congenital varicella syndrome.

From 1995 to 2013, a registry in the United States recorded the maternal and fetal outcomes of pregnant women who were inadvertently given a varicella-containing vaccine within 3 months before, or at any time during, pregnancy. Among the 860 prospectively enrolled women, the data revealed no evidence of congenital varicella syndrome. This included 95 live births to varicella-zoster virus–seronegative women who received the vaccine during the 1st or 2nd trimester when the risk for congenital varicella syndrome is highest.²² Of the liveborn infants in the study, 2.2% had major congenital anomalies, which is similar to rates reported in the general American population.

A non-immune pregnant household contact is not a contraindication to vaccinating a healthy child or adult in the same household with varicella-containing vaccine. The benefit of reducing the exposure of non-immune pregnant women to varicella by vaccinating healthy contacts outweighs any theoretical risks of transmission of vaccine virus to these women.

Breastfeeding women can receive varicella vaccine. Most live vaccines are not secreted in breast milk. Women who received varicella vaccine while breastfeeding showed no evidence of varicella-zoster virus DNA in breast milk samples, and no effects on breastfed infants have been reported.²³ 

See Vaccination for women who are planning pregnancy, pregnant or breastfeeding and Table. Vaccines that are contraindicated in pregnancy: live attenuated vaccines for more details.

People who are immunocompromised

Varicella-containing vaccines contain live attenuated viruses and are contraindicated in people who are immunocompromised. This means that varicella-containing vaccines are contraindicated in:

• people who are significantly immunocompromised as a result of a medical condition(s)
• people receiving high-dose systemic immunosuppressive therapy, such as chemotherapy, radiation therapy or oral corticosteroids 

See Vaccination for people who are immunocompromised for more information. 

For more details on using live attenuated vaccines in people receiving corticosteroid therapy, see Table. Recommended timing of live vaccine doses in adults and children taking corticosteroids.

Precautions

Vaccination after receiving immunoglobulin or a blood product

A recent blood transfusion with washed red blood cells is not a contraindication to varicella or MMRV vaccines.

People who have received an immunoglobulin-containing product should wait 3–11 months before receiving varicella or MMRV vaccine. This is because the immunoglobulin may impair the expected immune response to the vaccine.^15,21,24

The interval between receiving the blood product and the vaccine depends on the amount of immunoglobulin in each product.²¹ See Table. Recommended intervals between immunoglobulins or blood products, and measles-mumps-rubella, measles-mumps-rubella-varicella or varicella vaccination and Vaccination for people who have recently received normal human immunoglobulin and other blood products.

People may receive varicella-containing vaccine at the same time as anti-D immunoglobulin, but at different injection sites. They can also receive varicella-containing vaccine at any time after anti-D immunoglobulin. Anti-D immunoglobulin does not interfere with the antibody response to the vaccine.

Administration of immunoglobulin or a blood product after vaccination

People who have received a varicella-containing vaccine should not receive immunoglobulin-containing products for 3 weeks after vaccination, unless the benefits of receiving the blood product outweigh the benefits of vaccination. If a person receives an immunoglobulin-containing product within 3 weeks after a varicella-containing vaccine, they should be revaccinated later at the appropriate time, as indicated in Table. Recommended intervals between immunoglobulins or blood products, and measles-mumps-rubella, measles-mumps-rubella-varicella or varicella vaccination.

People may receive anti-D immunoglobulin at any time after a varicella-containing vaccine. 

People with HIV

Vaccination with live attenuated vaccines can result in a more extensive vaccine-associated rash or disseminated infection in people with AIDS.^25-28 However, the following people with HIV may receive 2 doses of varicella vaccine:^29-31

• asymptomatic children >12 months of age with an age-specific CD4⁺ count of ≥15%
• adults with a CD4⁺ cell count ≥200 cells per μL 

See People with HIV in Vaccination for people who are immunocompromised. 

There have been no studies on combination MMRV vaccines in asymptomatic people with HIV or people with an age-specific CD4⁺ count of ≥15%. Therefore, it is recommended that these groups receive MMR vaccine and monovalent varicella vaccine, not MMRV vaccine.^26,29-31

People receiving corticosteroid therapy

People on low-dose systemic corticosteroids can receive varicella-containing vaccines. Low-dose systemic corticosteroid therapy includes:

• children on doses of ≤2 mg per kg per day for less than 1 week
• people on doses of 1 mg per kg per day or alternate-day regimens for longer periods

People receiving high-dose corticosteroids can receive varicella-containing vaccines after they have stopped corticosteroid therapy for at least 1 month (see Contraindications).²⁶

Some experts suggest temporarily stopping lower doses of steroids 2–3 weeks before vaccination with live viral vaccines, if possible.^26,32

See also Vaccination for people who are immunocompromised.

People receiving long-term aspirin or salicylate therapy

There is no need to avoid salicylates before or after receiving varicella or MMRV vaccine.

People taking long-term salicylate therapy (aspirin) can receive varicella-containing vaccine, if needed. The benefit is likely to outweigh any possible risk of Reye syndrome after vaccination.

Natural varicella infection and salicylate use have been associated with an increased risk of developing Reye syndrome. However, there are no reports of an association between Reye syndrome and varicella vaccination (see Variations from product information).

People with possible IFNAR1 deficiency

IFNAR1 deficiency is a rare inherited condition affecting some people of Western Polynesian heritage, including Tongan, Samoan and Niuean. It is associated with severe illness and death from certain viral infections and also potentially from some live attenuated viral vaccines, including the measles, mumps and rubella (MMR) vaccine, the yellow fever virus vaccine and potentially varicella vaccine, though disseminated varicella post vaccination has not been seen.^33,34 Currently, diagnosis of IFNAR1 deficiency prior to vaccination is challenging and there is no established treatment.

Healthcare providers need to be aware that children of Western Polynesian heritage who present for medical attention and are very unwell in the 1-2 weeks following an MMRV or varicella vaccine may need further investigation by an immunologist to assess for an immune deficiency. Any suspected adverse event following immunisation should be reported. Family members of individuals who have had a severe reaction to a live attenuated viral vaccine, or are related to someone with known IFNAR1 deficiency, should be referred to an immunologist before having the MMRV or varicella vaccine. Children who have safely received a first dose of MMRV or varicella vaccine are highly unlikely to have IFNAR1 deficiency.³³

Advice on vaccination of children or adults who have been diagnosed with IFNAR1 or any other specific immune deficiency should be sought from their immunologist.

Personal or close family history of seizures or convulsions

Children with a personal or close family history of seizures or convulsions can receive MMRV vaccine.

Ensure that the parents or carers understand that the child may develop a fever 6–14 days after vaccination.³⁵ Advise parents or carers about how to manage the fever with paracetamol and other measures (see Adverse events following immunisation).

MMRV vaccines are only recommended for use as the 2nd dose of measles-containing vaccine. This is because the risk of fever and febrile convulsions is higher if children receive MMRV vaccine as their 1st dose. See Recommendations and Adverse events. 

Tuberculin skin testing after MMRV vaccination

Measles virus inhibits the response to tuberculin. Tuberculin-positive people may become tuberculin-negative for 4–6 weeks after measles infection, and measles-containing vaccines have a similar effect.^35,36 Because of this, a tuberculin skin test (TST; Mantoux) may be unreliable for at least 4–6 weeks in people who have received MMRV vaccine.

There are no studies on if and how MMRV vaccination affects the results of interferon-gamma release assays used for testing for M. tuberculosis infection.³⁷

Adverse events following varicella-containing vaccines are generally mild and well tolerated.³⁸

Common adverse events

The most common adverse events are injection site reactions:

• pain
• redness
• swelling

These occur in 7–30% of vaccine recipients.^38,39

Rashes

Around 5% of vaccine recipients may develop a maculopapular or papulovesicular rash, usually within 5–26 days. This usually lasts for less than 1 week.^40,41 Vaccine-associated rashes typically comprise 2–5 lesions, and may be generalised (3–5% of vaccine recipients). They also commonly occur at the injection site (3–5% of vaccine recipients).⁴²

Vaccine-associated rash may be atypical and may not be vesicular. Most varicelliform rashes that occur within the first 2 weeks after vaccination are from wild-type varicella-zoster virus. These have a median onset 8 days after vaccination (range 1–24 days). Vaccine-strain rashes occur a median of 21 days after vaccination (range 5–42 days).^43,44

Fever and febrile convulsions

After varicella vaccination:

• 15% of healthy children develop a fever >39°C, which is comparable to that seen in children receiving placebo⁴¹
• 10% of adults and adolescents develop a fever⁴⁵

Inform vaccine recipients, or their parents or carers, about:

• possible symptoms occurring 5–12 days after vaccination
• how to manage the symptoms, including using paracetamol for fever

See Adverse events following immunisation.

In clinical trials, people who received MMRV vaccine had higher rates of fever than people who received MMR vaccine and monovalent varicella vaccine at the same time but at separate sites.^46-49 Rates of fever were highest in young children who received MMRV vaccine as their 1st dose.

Post-marketing studies in the United States identified an approximately 2-fold increased risk of fever and febrile convulsions 7–10 days⁵⁰ (or 5–12 days)⁵¹ after vaccination in children who received MMRV vaccine as a 1st dose. MMRV recipients were compared with recipients of separate MMR and varicella vaccines. MMRV vaccination resulted in 1 additional febrile seizure for every 2300 doses compared with separate MMR and varicella vaccination.⁵⁰ Children in these studies were mostly 12–23 months of age.

In the United States, post-marketing studies did not find an increase in fever or febrile convulsions after children received the 2nd dose of ProQuad (MMRV) vaccine. However, most 2nd dose recipients were aged 4–6 years, an age at which the incidence of febrile convulsions is low.⁵² This side effect profile is expected to be similar in children who receive Priorix-tetra.

Rare adverse events

Transmission of vaccine virus

It is rare for vaccine recipients to transmit the vaccine virus to their contacts.

The United States distributed more than 56 million doses of varicella vaccine between 1995 and 2005. During this time, there were only 6 well-documented cases of the vaccine-type virus being transmitted, from 5 healthy vaccine recipients who had a vaccine-associated rash.^42,53 Contact cases were mild.^42,53-55

Herpes zoster (shingles)

Rarely, vaccine recipients can develop herpes zoster, or shingles. This has been attributed to both the vaccine strain and wild-type varicella virus reactivation.⁴³

It is rare for the vaccine virus to reactivate and cause herpes zoster. In most cases, herpes zoster can be linked to reactivation of wild-type virus after an unknown previous infection. The risk of developing herpes zoster is probably lower after vaccination than after natural varicella infection. Reported cases of herpes zoster after vaccination have been mild.³⁹

In children 0–9 years of age, herpes zoster rates after natural varicella infection were about 30–74 per 100,000 per year.^56,57 A 9-year follow-up of 7000 children who received varicella vaccine reported a herpes zoster rate of 22 per 100,000 person-years.¹⁵

See also Herpes zoster.

Other rare adverse events

A post-marketing study in the United States reported some serious adverse events that were linked to varicella vaccination but not necessarily causally related. These events were very rare and occurred in <0.01% of doses distributed. They included:^10,44

• encephalitis
• ataxia
• thrombocytopenia
• anaphylaxis

There were no neurological adverse events after varicella vaccination in which the Oka vaccine virus strain was detected in cerebrospinal fluid.

People with an egg allergy can safely receive MMRV vaccine.⁵⁸ Skin testing is not needed before vaccination.⁵⁹ Anaphylaxis after vaccination is likely due to anaphylactic sensitivity to gelatin or neomycin, not an egg allergy. Measles and mumps (not rubella or varicella) vaccine viruses are grown in chick embryo tissue cultures, but measles- and mumps-containing vaccines have negligible amounts of egg ovalbumin. See Variations from product information and Vaccination for people who have had an adverse event following immunisation.

Varicella-zoster virus (VZV) is a DNA virus in the herpesvirus family.⁶⁰

Pathogenesis

Varicella is a highly contagious viral infection. Primary infection with VZV causes varicella (chickenpox). After primary infection, VZV establishes latency in the dorsal root ganglia. Reactivation of the latent virus manifests as herpes zoster (shingles)³⁷ (see Herpes zoster).

The average incubation period is 14–16 days (range 10–21 days). This may be longer in people who are immunocompromised, especially after receiving zoster immunoglobulin.³⁹ The period of infectivity is from 48 hours before the onset of the rash until all lesions have crusted over.⁶¹

Transmission

Varicella spreads:⁶⁰

• by respiratory secretions, including aerosol transmission
• from the vesicle fluid of the skin lesions of varicella or herpes zoster infection

Symptoms of varicella

Varicella is usually a mild childhood disease.

A short prodromal period of 1–2 days may precede the onset of the rash, especially in adults.^39,60

Children who are otherwise healthy usually develop 200–500 skin lesions.^39,60

Approximately 5% of cases are subclinical.

Breakthrough varicella

Breakthrough varicella is a case of wild-type varicella occurring more than 42 days after vaccination. Most breakthrough varicella cases are mild, with fewer lesions than natural infection. However, breakthrough varicella infections can be contagious, especially if many lesions are present.⁶²

Complications of varicella

Complications occur in about 1% of cases.⁶³ Varicella is more severe in adults, particularly in pregnant women and people of any age who are immunocompromised. People who are immunocompromised can develop disseminated disease or die from varicella complications.⁶⁰

Acute varicella may be complicated by:⁶⁰

• secondary bacterial skin infection
• pneumonia
• acute cerebellar ataxia (1 in 4000 cases)
• aseptic meningitis
• transverse myelitis
• encephalitis (1 in 100,000 cases) 
• thrombocytopenia 

In rare cases, varicella involves the viscera and joints.⁶⁰

Congenital varicella syndrome

Varicella infection in pregnancy may result in congenital varicella syndrome in the infant. These infants may have:^60,64

• skin scarring
• limb defects
• ocular anomalies
• neurological malformations 

The fetus has a higher risk of developing congenital varicella syndrome if the mother is infected during the 2nd trimester compared with the 1st trimester (1.4% versus 0.55%).⁶⁵ The fetus is also at risk of developing herpes zoster in infancy (0.8–1.7%). This risk is highest if the mother is infected during the 3rd trimester.⁶⁴

Infants born to mothers who have perinatal varicella infection can have severe neonatal varicella infection.⁶⁶ Varicella in pregnant women from 5 days before delivery to 2 days after delivery results in severe varicella in about 17–30% of newborn infants.^60,66 

Herpes zoster (shingles)

Latent varicella virus can reactivate as the result of waning cellular immunity, which manifests as herpes zoster. This is a localised vesicular rash. Herpes zoster can occur at any age, but is more common in older adults and people who are immunocompromised. Complications may include:⁶⁰

• post-herpetic neuralgia 
• disseminated herpes zoster, which may involve the visceral organs, the central nervous system or the lungs (see Herpes zoster)

In an unimmunised population in temperate climates, the annual number of cases of varicella approximates the birth cohort.⁶⁷ That is, almost all unimmunised children will develop varicella. Tropical regions have a higher proportion of cases in unimmunised adults.

Varicella in Australia

Varicella vaccine was included on the National Immunisation Program in 2005. Each year before this, there were about:^68-70

• 240,000 cases of varicella
• 1500 hospitalisations as result of varicella
• an average of 7–8 deaths due to varicella

In the first 2.5 years after 2005, children aged 1.5–4 years had a 69% decline in varicella hospitalisations.⁷¹ Hospitalisation rates in other age groups and general practice consultations also declined.^71-73 Most hospitalisations from varicella infection are now in children <18 months of age who are too young to be vaccinated. There has been little change in varicella hospitalisation rates since 2010. The rate in 2013 was 2.1 per 100,000 population.⁷⁴

People receive varicella vaccine as either monovalent varicella vaccine or MMRV vaccine. All available varicella-containing vaccines are derived from the Oka varicella-zoster virus strain, but have some genetic differences.⁷⁵

Monovalent varicella vaccine

Post-marketing studies in the United States estimated the effectiveness of 1 dose of varicella vaccine in children to be:^62,76-79

• 80–85% against any disease
• 95–98% against severe varicella

Although earlier data suggested that immunity persisted in most healthy vaccine recipients,⁶⁰ some long-term follow-up studies showed that rates of vaccine failure increased over time in 1-dose vaccine recipients. For example, 1 study showed that vaccine failure was 2.6 times more likely in children who had received 1 vaccine dose more than 5 years ago than in children who had received 1 vaccine dose within 5 years.⁸⁰

Follow-up from a randomised controlled trial in children 12 months to 12 years of age, comparing 1 dose with 2 doses of varicella vaccine over 10 years, showed significantly higher protection with 2 doses (98.3% versus 94.4%).¹ Based on current evidence, 2 doses of a varicella-containing vaccine in children from 12 months of age will minimise the risk of breakthrough varicella (see Recommendations).

Healthy adolescents (≥14 years of age) and adults need 2 doses of varicella vaccine, at least 4 weeks apart. This is because the response to a single dose of varicella vaccine decreases with age and does not provide adequate protection.²

Combination MMRV vaccines

Clinical trials of MMR compared with MMRV vaccine were mainly done in children 12 months to 6 years of age. MMRV vaccines produce similar rates of seroconversion to all 4 vaccine components as MMR and monovalent varicella vaccines given at the same time at separate injection sites.^46-49

One study compared seroresponsiveness to a single MMRV vaccine dose in children aged 12–14 months. The seroresponse rates to measles, mumps and rubella were similar, but varicella seroresponses were lower in Priorix-tetra recipients than in ProQuad recipients.¹⁹ However, the clinical significance of this is not clear, particularly for MMRV vaccine given after MMR vaccine.

Transport according to National vaccine storage guidelines: Strive for 5.⁸¹ Store at +2°C to +8°C. Do not freeze. Protect from light.

Varicella-containing vaccines are less stable than other commonly used live viral vaccines. It is very important to follow storage and reconstitution instructions.

All varicella-containing vaccines must be reconstituted. Add the entire contents of the diluent container to the vial containing the pellet. Shake until the pellet completely dissolves.

Available monovalent varicella and MMRV vaccines have different requirements after reconstitution:

• Use reconstituted Varilrix vaccine as soon as practicable. If it must be stored, hold at 25°C for no more than 90 minutes, or at +2°C to +8°C for no more than 8 hours.
• Use reconstituted Varivax Refrigerated vaccine within 2.5 hours.
• Use reconstituted Priorix-tetra (MMRV) vaccine as soon as practicable. If it must be stored, hold at +2°C to +8°C for no more than 8 hours.
• Use reconstituted ProQuad (MMRV) vaccine immediately. If it must be stored, hold at +2°C to +8°C for no more than 2.5 hours, or at +20°C to +25°C for no more than 1 hour.

Notifying varicella

Varicella is a notifiable disease in most states and territories in Australia.

State and territory public health authorities can provide advice about the public health management of varicella, including management of cases and contacts.

Managing varicella cases

There is no specific therapy for uncomplicated varicella infection. Antiviral therapy can treat:

• complicated or severe varicella
• herpes zoster disease
• disease in people who are immunocompromised

Zoster immunoglobulin does not treat established varicella or zoster infection.

Managing contacts of varicella cases

‘Significant exposure’ to varicella-zoster virus is defined as:

• living in the same household as a person with active varicella or herpes zoster
• direct face-to-face contact with a person with varicella or herpes zoster for at least 5 minutes
• being in the same room with a person with varicella or herpes zoster for at least 1 hour

In the case of varicella infection, the period of infectivity is from 48 hours before the onset of rash until all lesions have crusted over. A person with localised herpes zoster is less likely to transmit the virus than someone with varicella.⁶¹

Vaccination for post-exposure prophylaxis

For post-exposure vaccination, people should receive varicella vaccine within 5 days after exposure, and preferably within 3 days.^82-86

If varicella vaccine is not contraindicated, it can be offered to non-immune age-eligible children and adults who have had a significant exposure to varicella or herpes zoster and want protection against primary infection with varicella.^82-86

Vaccination reduces the likelihood of varicella infection after exposure, especially moderate to severe disease. It also provides long-term protection. Vaccinating exposed people during outbreaks prevents further cases and controls outbreaks.⁸⁶

If a child <14 years of age also needs MMR vaccination, use MMRV vaccine. However, MMRV vaccine is not routinely recommended as the 1st dose of MMR-containing vaccine in children aged <4 years (see Recommendations).

Zoster immunoglobulin

The Australian Red Cross Blood Service provides restricted amounts of high-titre zoster immunoglobulin (ZIG). ZIG prevents varicella in people at high risk who report a significant exposure to varicella or herpes zoster. ZIG is not used to treat established varicella or zoster infection.

ZIG is highly efficacious, but is often in short supply. Use normal human immunoglobulin (NHIG) to prevent varicella if ZIG is unavailable.

Serological testing

People with primary or acquired diseases associated with cellular immune deficiency and people receiving immunosuppressive therapy should be tested for varicella-zoster antibodies after contact with confirmed varicella. However, do not delay giving ZIG while waiting for the test results (see High-risk groups).^87-89

Test immunocompetent varicella contacts for varicella-zoster antibodies. If the contact is non-immune and age-eligible, they can receive a varicella-containing vaccine (see Vaccination for post-exposure prophylaxis in this section).

High-risk groups

People in high-risk groups should receive ZIG according to Table. Zoster immunoglobulin dose based on weight, preferably within 96 hours and up to 10 days after exposure. Do not delay ZIG therapy while waiting for varicella-zoster antibody test results.

The high-risk groups that should receive ZIG are:

• pregnant women who are presumed to be susceptible to varicella infection — if practical, test them for varicella-zoster antibodies before they receive ZIG⁶⁴
• neonates whose mothers develop primary varicella infection within 7 days before delivery to 2 days after delivery — these neonates must receive ZIG, as early as possible in the incubation period, because neonatal mortality without ZIG is up to 30%^60,66
• neonates exposed to varicella in the 1st month of life, if the mother has no personal history of infection with varicella virus and is seronegative¹⁵ — these neonates should receive ZIG, because of the increased risk of severe varicella in newborns of seronegative women
• premature infants (<28 weeks gestation or birth weight <1000 g) exposed to varicella while still hospitalised — these infants should receive ZIG regardless of maternal history of varicella
• patients with primary or acquired diseases associated with cellular immune deficiency, and people receiving immunosuppressive therapy^88,89

If a contact who is immunocompromised has recent evidence of detectable antibodies, they do not need ZIG. ZIG will not significantly increase varicella-zoster antibody titres in those who are already antibody positive.

Varicella-zoster antibodies detected in patients who have received a transfusion, or intravenous immunoglobulin or ZIG in the previous 3 months may be passively acquired and transient.

Repeat ZIG doses

If a person is exposed to varicella again >3 weeks after the 1st dose of ZIG, repeat the ZIG dose.

However, also test for varicella-zoster antibodies. Use NHIG if ZIG is unavailable.

People receiving monthly high-dose intravenous NHIG are likely to be protected and probably do not need ZIG if they received the last dose of NHIG ≤3 weeks before exposure.

All varicella-containing vaccines

The product information for all varicella-containing vaccines states that people should avoid taking salicylates for 6 weeks after vaccination. This is because Reye syndrome has been reported after using salicylates during natural varicella infection.

The Australian Technical Advisory Group on Immunisation (ATAGI) recommends that non-immune people on long-term salicylate therapy can receive varicella-containing vaccines, as the benefit is likely to outweigh any possible risk of Reye syndrome after vaccination.

Varilrix and Varivax Refrigerated

Varilrix and Varivax Refrigerated are registered for use as 2 doses of 0.5 mL (1–2 months apart) in adolescents ≥13 years of age and adults.

ATAGI recommends that:

• children <14 years of age receive at least 1 dose of varicella vaccine
• adolescents ≥14 years of age receive 2 doses of varicella vaccine 

Varilrix

The product information for Varilrix states that adults and adolescents who receive 2 doses of varicella vaccine should receive the 2nd dose at least 6 weeks after the 1st dose.

ATAGI recommends that the 2nd dose may be given at least 4 weeks after the 1st dose. 

Varivax Refrigerated

The product information for Varivax Refrigerated recommends that women of child-bearing age should avoid pregnancy for 3 months after vaccination. 

ATAGI recommends that these women should avoid pregnancy for 28 days after vaccination,¹⁵ as for other monovalent varicella vaccines and MMRV vaccines.

The product information for Varivax Refrigerated recommends delaying vaccination for 5 months after an individual receives normal human immunoglobulin by intramuscular injection or blood transfusion. 

ATAGI recommends that people should not receive a varicella-containing vaccine for at least 3 months after receiving immunoglobulin-containing blood products, according to the intervals outlined in Table. Recommended intervals between immunoglobulins or blood products, and measles-mumps-rubella, measles-mumps-rubella-varicella or varicella vaccination.

Priorix-tetra and ProQuad

The product information for Priorix-tetra and ProQuad states that people with a history of anaphylactic or anaphylactoid reactions to egg should not receive these vaccines.

ATAGI recommends that these people can receive Priorix-tetra or ProQuad.³⁵

The product information for ProQuad states that this vaccine is for use in children 12 months to 12 years of age. The product information for Priorix-tetra states that children ≥9 months of age can receive this vaccine.

ATAGI recommends that children up to 14 years of age can receive both MMRV vaccines. ATAGI also recommends that MMRV vaccine should not be used routinely as the 1st dose of MMR-containing vaccine in children aged <4 years.

ProQuad

The product information for ProQuad recommends that women of child-bearing age should avoid pregnancy for 3 months after vaccination.

ATAGI recommends these women should avoid pregnancy for 28 days after vaccination,³³ as for Priorix-tetra.

Zoster immunoglobulin

The product information for zoster immunoglobulin recommends different doses from those in Table. Zoster immunoglobulin dose based on weight. The doses in the table aim to minimise wastage of zoster immunoglobulin.

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