Since the publication of the 2006 Canadian Immunization Guide:
For further information, refer to the National Advisory Committee on Immunization (NACI) Statements: Statement on Measles-Mumps-Rubella-Varicella Vaccine; Updated Recommendations for the use of Varicella and MMR Vaccines in HIV-infected Individuals; and Varicella vaccination two-dose recommendations.
Varicella (chickenpox) is a generalized viral disease caused by varicella zoster virus (VZV), a deoxyribonucleic acid (DNA virus) of the Herpesvirus family.
VZV is spread by the airborne route as well as by direct contact with the virus shed from skin lesions. The attack rate among susceptible contacts in household settings is estimated at 65% to 87%. The incubation period is from 10 to 21 days after exposure, usually 14 to 16 days. Infectiousness begins 1 to 2 days before onset of the rash and lasts until the last lesion has crusted.
Varicella has been considered to be a benign disease in otherwise healthy children up to 12 years of age. Risk of severe varicella infection increases with age. Adults and, in particular, pregnant women are at increased risk of severe disease. However, because most infections occur in children up to 12 years of age in unvaccinated communities, the majority of severe cases occur in this age group. Children up to 12 years of age account for 80% to 85% of varicella-associated physician visits, 85% to 90% of hospitalizations, and nearly 50% of fatal cases. Children with impaired immunity are at risk of severe varicella and death.
Varicella disease increases during the school year and decreases sharply during summer vacation.
Spectrum of clinical illness
Symptoms of varicella include low-grade fever, mild constitutional symptoms, and a generalized, pruritic rash, with lesions at different stages that progress rapidly from macules to papules to vesicular lesions before crusting. The main complications of varicella include secondary bacterial skin and soft tissue infections, bacteremia, pneumonia, osteomyelitis, septic arthritis, necrotizing fasciitis, toxic shock-like syndrome, cerebellar ataxia, stroke and encephalitis. Varicella increases the risk of severe invasive group A streptococcal infection in previously healthy children by 40-fold to 60-fold. Complications are more common in adolescents, adults and people with conditions that compromise their immune system who have higher rates of pneumonia, encephalitis and death.
Congenital varicella syndrome is rare when infection occurs before the 13th or after the 20th week of gestation. The risk is approximately 2% when infection occurs at between 13 and 19 weeks of gestation. Congenital infection results in a wide clinical spectrum, which may include low birth weight, ophthalmic abnormalities, skin scarring, limb atrophy, cerebral atrophy and a variety of other anomalies. Maternal varicella occurring in the 5 days before to 2 days after birth is associated with severe neonatal varicella in 17% to 30% of infants, with high case fatality for the newborn.
Varicella case fatality rates are highest among adults (30 deaths/100,000 cases) followed by infants under 1 year of age (7 deaths/100,000 cases) and those aged 1 to 19 years (1 to 1.5 deaths/100,000 cases). In Canada, 70% of the 59 varicella related deaths in the years 1987 to 1997 (pre-vaccine) occurred in those over 15 years of age. Between 2000 and 2009, a total of 10 pediatric deaths due to varicella were reported by the Immunization Monitoring Program ACTive (IMPACT) system, with a range of 0 to 3 deaths per year.
Varicella occurs worldwide and, in countries without vaccination programs, it is mainly a disease of childhood, developing in 50% of children by the age of 5 years and 90% by the age of 12 years. The epidemiology of varicella is similar among developed countries such as the United Kingdom (UK), the United States (US), and Canada. No significant gender difference has been found. People from tropical regions (including South Asia, South East and East Asia) are less likely to acquire immunity in childhood and, therefore, have higher rates of susceptibility as adults.
In the US, there were approximately 4 million varicella cases annually before varicella vaccine was licensed in 1995. The incidence of varicella, as well as varicella-related hospitalizations, has decreased significantly in the post-vaccine era. Varicella-related hospitalizations in the US decreased from 2.3-5 per 100,000 population (1993-1995) to 0.3-1.3 per 100,000 population (2001-2002) and ambulatory care visits for varicella declined by 59%. In 2000, the number of varicella-related deaths in the US had declined by 78% in the under-20-year age group and by 63% in the 20-year to 49-year age group, as compared with the pre-vaccine years, 1990 to 1994.
In the pre-vaccine era, it is estimated that there were approximately 350,000 varicella cases and 1,500 to 2,000 varicella-related hospitalizations each year in Canada. However, assessing the effect of varicella immunization programs on the incidence of the disease is difficult as varicella infections are significantly under-reported, with less than 10% of the expected cases reported annually. Canadian studies have found decreases in the burden of varicella following the introduction of immunzation programs. Alberta saw a significant decline in disease incidence compatible with a vaccination program effect. Following introduction of publicly funded varicella vaccination in Ontario, varicella-related hospitalizations, emergency department use, and visits to physicians’ offices decreased 53%, 43% and 45% respectively.
Information on pediatric hospitalized cases and deaths are available from the IMPACT system for the periods 1990 to 1996 and 1999 to 2009. These data indicate that the majority of hospitalizations occur in previously healthy children. Among these cases, children younger than 10 years of age were mainly affected and accounted for 16.5% (age less than 1 year) and 75.5% (age 1-9 years) of the total hospitalizations. Since 2004, the annual average number of varicella hospitalizations at IMPACT centers has dropped from 300 (2000 to 2004) to 114 (2005 to 2009).
For complete prescribing information, consult the product leaflet or information contained within Health Canada’s authorized product monographs available through the Drug Product Database. Refer to Table 1 and Table 2 in General Considerations in Part 1 for lists of all vaccines and Passive Immunization available for use in Canada and their contents.
The rate of breakthrough varicella disease in vaccinees following one dose of varicella vaccine has been estimated at 7.2% over a 10-year follow-up period. American data estimate the overall effectiveness of a single dose vaccination program to be between 70% and 90% in preventing varicella disease of any severity, and 95% in protecting against severe varicella for at least 7 to 10 years after immunization. However, despite high vaccination coverage, limitations of the single dose regimen in achieving varicella control have been identified in the US. Primary vaccine failure and waning immunity appear to be responsible for breakthrough disease.
A two-dose primary schedule for children 12 months to 12 years of age has improved varicella control. In a 10-year prospective study, the cumulative risk of breakthrough disease was 3.3-fold lower in children who received two doses of varicella vaccine compared to children who received one dose. The estimated vaccine effectiveness was 98.3% after two doses, significantly higher than after one dose (94.4%). The 2-dose regimen was 100% efficacious against severe varicella.
There are no data regarding the efficacy of MMRV vaccine.
In healthy children 12 months to 12 years of age, a single univalent varicella vaccine dose results in a seroconversion rate of 98% at 4 to 6 weeks after vaccination with antibodies persisting in 98% at 5 years and 96% at 7 years after vaccination. A second dose of a univalent varicella vaccine in children produces an improved immunologic response that is correlated with improved protection. In adults and adolescents 13 years of age and older, two vaccine doses administered 4 to 8 weeks apart result in seroconversion rates of 99% at 4 to 6 weeks after the second dose, with persistence of antibodies 5 years later in 97%.
In a study of 12-month-old children, a single dose of MMRV vaccine resulted in a seroconversion rate for measles, mumps, rubella and varicella of 98%, 97%, 98% and 93%, respectively. The seroconversion rates and geometric mean titres for individual components were not significantly different from those achieved after MMR plus a univalent varicella vaccine or MMR vaccine alone. A study of children receiving two doses of MMRV vaccine during the second year of life noted seropositivity for measles, mumps, rubella and varicella of 99%, 97.4%, 100% and 99.4% respectively by the third year post-vaccination. Long-term persistence of anti-measles, anti-mumps, anti-rubella and anti-varicella antibodies following MMRV vaccinations are under evaluation.
Children (12 months to 12 years of age)
Two doses of varicella-containing vaccine (univalent varicella or MMRV) should be given for routine immunization of children and for immunization of children who have missed varicella immunization on the routine schedule.
Children with a history of varicella disease occurring before 12 months of age should receive routine immunization with two doses of varicella-containing vaccine after 12 months of age, because varicella disease at less than 12 months of age has been associated with an increased risk of a second episode of varicella. Children who receive one dose of varicella-containing vaccine and subsequently develop laboratory confirmed breakthrough infection do not require a second dose of a varicella-containing vaccine for varicella protection.
Adolescents (13 to 17 years of age)
Adolescents without contraindications who may be susceptible to varicella (refer to Susceptibility and immunity for a definition of susceptible) should be serologically tested for varicella antibodies because the majority of such adolescents will be immune. If the adolescent is shown to be serologically susceptible to varicella, the person should receive two doses of a univalent varicella vaccine (as MMRV is not authorized in this age group) a minimum of 6 weeks apart. In adolescents with documentation of receiving only one dose of a varicella-containing vaccine, a second dose should be offered.
Adults (under 50 years of age) without contraindications who may be susceptible to varicella (refer to Susceptibility and immunity for a definition of susceptible) should be serologically tested for varicella antibodies because the majority of such adults will be immune. If an adult under the age of 50 years is shown to be serologically susceptible to varicella, the person should receive two doses of univalent varicella vaccine. Adults (under 50 years of age) who received only one dose of varicella vaccine should be offered a second dose.
In adults aged 50 years and older, routine serologic testing is not recommended. Nearly all Canadians 50 years of age and older, will have had prior varicella exposure even if the person does not remember having had chickenpox or herpes zoster. In the rare circumstance that an adult aged 50 years and over is known to be serologically susceptible to varicella based on previous testing for another reason, and is without contraindications, the individual should be vaccinated with two doses of univalent varicella vaccine. For other adults 50 years of age and over, refer to Herpes Zoster (Shingles) Vaccine in Part 4 for additional information.
A self-reported history of varicella is considered a reliable history of varicella disease in individuals born before 2004 (with the exception of health care workers). For children born in 2004 or later and health care workers, a health care provider diagnosis of varicella or herpes zoster is necessary to be considered a reliable history of varicella disease.
Individuals who have one or more of the following are considered immune to varicella. Individuals who do not have ANY of the following are considered susceptible to varicella:
Recipients of hematopoietic stem cell transplant should be considered susceptible in the post-transplantation period regardless of a history of varicella disease or vaccination, or positive serologic test results.
The following groups are priorities for varicella immunization if susceptible:
Refer to Schedule.
Children and adults, who are susceptible to varicella, including those lacking adequate documentation of immunization, should be started on an immunization schedule appropriate for their age and risk factors. Varicella-containing vaccine may be given regardless of possible previous receipt of the vaccine because adverse events associated with repeated immunization have not been demonstrated. Refer to Immunization of Children and Adults with Inadequate Immunization Records in Part 3 for additional general information.
Immunity to varicella should be reviewed in women of reproductive age and vaccination should be recommended to susceptible non-pregnant women. Women should delay pregnancy by at least 4 weeks following vaccination with a univalent varicella vaccine.
Varicella-containing vaccine is contraindicated in pregnancy because there is a theoretical risk to the fetus; however, there is no evidence to demonstrate a teratogenic risk from the vaccine. Termination of pregnancy should not be recommended following inadvertent immunization with varicella vaccine on the basis of fetal risks following maternal immunization. Incidents of inadvertent varicella immunization during pregnancy, or of pregnancy occurring within 3 months after immunization with VARIVAX® III, should be reported to the registry maintained by Merck Canada Inc., Medical Services (telephone: 1-800-684-6686). GlaxoSmithKline Inc. does not maintain a pregnancy outcome registry for VARILRIX®.
Women who are breastfeeding and individuals in households where there is a newborn can be vaccinated with a univalent varicella vaccine.
Most residents of long-term care facilities will be immune to varicella. Postpartum women susceptible to varicella should be vaccinated before discharge. Refer to Immunization of Patients in Health Care Institutions in Part 3 for additional general information.
In general, immunocompromised persons should not receive live vaccines because of the risk of disease caused by the vaccine strains. When considering immunization of an immunocompromised person, approval from the individual’s attending physician should be obtained before vaccination. For complex cases, referral to a physician with expertise in immunization and/or immunodeficiency is advised.
In Canada, only VARILRIX® has received authorization for the vaccination of select groups of immunocompromised people; however, VARIVAX® III may also be used. MMRV vaccine has not been studied in persons with impaired immune function, including primary or secondary immunodeficiency disorders, and so is not recommended for this group.
In immunosuppressed people, antibody testing may be considered 6 to 8 weeks after the last dose of univalent varicella vaccine is given. Local antibody assays may not be sensitive enough to detect antibody after vaccination. For the purposes of post-exposure prophylaxis, an immunosuppressed person with a negative test should be considered non-immune. Therefore, if antibody is not detectable, consider offering immunocompromised persons VarIg upon subsequent exposures to wild-type varicella. Refer to Figure 1, Table 1 and Post-exposure immunization.
People who have a suspicious history for immunodeficiency disorders (e.g., known or suspected family history of congenital immunodeficiency disorder or HIV infection, or a history of failure to thrive and recurrent infections) should not be immunized until they have been fully investigated and T cell dysfunction ruled out.
Live vaccines are generally not recommended for patients with congenital immunodeficiency states although some exceptions exist.
B cell deficiency
Univalent varicella vaccine should be considered if the individual is not receiving regular immune globulin replacement therapy, which may affect the efficacy of the vaccine. People with isolated humoral immunoglobulin deficiency disorders and known intact T cell systems may be vaccinated with two doses of univalent varicella vaccine at least 3 months apart.
T cell, natural killer T cell, and mixed cellular and antibody defects (e.g., Severe Combined Immune Deficiency [SCID])
All live vaccines, including varicella-containing vaccine, are contraindicated in people with defects in T cell function.
and neutrophil disorders (e.g., congenital neutropenia, leukocyte adhesion and
migration defects, chronic granulomatous disease)
Children with phagocytic or neutrophil disorders may be vaccinated with two doses of univalent varicella vaccine at least 3 months apart.
Persons with complement deficiency disorders may be vaccinated with two doses of univalent varicella vaccine at least 3 months apart. Because immunity can decrease over time, assessment of antibody titres and re-immunization, if needed, should be considered.
Malignant hematologic disorders
Varicella-containing vaccine is contraindicated in individuals with severe immunodeficiency due to conditions such as: blood dyscrasias, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic systems.
Varicella-containing vaccine is contraindicated in people undergoing immunosuppressive treatment for acute leukemia. Children with Acute Lymphocytic Leukemia (ALL) may be vaccinated with univalent varicella vaccine if the disease has been in remission for at least 12 months, the child's total lymphocyte count is at least 1.2 × 109/L, the child is not receiving radiation therapy, and maintenance chemotherapy can be withheld for at least 1 week before to 1 week after immunization. Two doses of univalent varicella vaccine may be given, at least 3 months apart.
Hematopoietic stem cell transplantation (HSCT- autologous or allogeneic)
Malignant solid tumours
Varicella-containing vaccine is contraindicated in people undergoing immunosuppressive treatment for any malignant solid tumours.
Solid organ transplantation
Varicella vaccination is recommended before transplantation for susceptible (as determined by serology) children and adults. Ideally, and if time permits, two doses of univalent varicella vaccine should be given at least 3 months apart with the last dose being given at least 6 weeks prior to transplantation. If time does not permit administration of a two-dose series, one dose of univalent varicella vaccine should be given and the transplant delayed by at least 4 weeks. The person should not be receiving immunosuppressive treatment at the time of vaccination. Varicella-containing vaccine is not recommended after solid organ transplantation.
Vaccination status for varicella should be reviewed for immunocompetent persons who might be anticipating initiation of immunosuppressive treatments or who have diseases that might lead to immunodeficiency.
If indicated, varicella vaccine should be administered at least 4 weeks before the initiation of immunosuppressive therapy (e.g., high-dose systemic corticosteroids [2 mg/kg per day or more of prednisone or its equivalent or 20 mg/day or more of prednisone or its equivalent] for 14 days or more; chemotherapy; radiation therapy; azathioprine; cyclosporine; cyclophosphamide; infliximab). If this cannot be done, a period of at least 3 months should elapse after immunosuppressive drugs (except high-dose systemic corticosteroids) have been stopped before administration of live vaccines. A period of at least 4 weeks should elapse between discontinuation of high-dose systemic steroids and the administration of live vaccines. The interval between discontinuation of immunosuppressive drugs and varicella vaccine administration may vary with the intensity of the immunosuppressive therapy, underlying disease and other factors. If immunosuppressive therapy cannot be stopped, live vaccines are generally contraindicated, although the risk-to-benefit ratio may favour immunization if only low doses of immunosuppressive drugs are required and there is significant risk of varicella infection.
Corticosteroid therapy is not a contraindication to administering a live vaccine when steroid therapy is short-term (i.e., less than 14 days); or a low-to-moderate dose (less than 20 mg of prednisone or equivalent per day for an adult); or long-term, alternate-day treatment with short-acting preparations; or maintenance physiologic replacement therapy; or administered topically, inhaled, or locally injected (e.g., joint injection).
An infectious disease specialist/immunologist should be consulted for advice on varicella immunization in HIV-infected people. Varicella vaccine is contraindicated in persons with advanced HIV/AIDS. The safety and immunogenicity of MMRV vaccine in HIV-infected individuals has not been evaluated, and MMRV vaccine is not routinely recommended.
Susceptible household contacts of immunocompromised people should receive varicella-containing vaccine as appropriate for age and risk factors. If the vaccine recipient develops a varicella-like rash, the rash should be covered and the vaccinee should avoid direct contact with the immunocompromised person for the duration of the rash. Secondary transmission from people with post-vaccination varicella-like rashes can occur rarely.
Hyposplenism or asplenia
Hyposplenic or asplenic (congenital absence, surgical removal or functional [e.g., sickle cell disease]) individuals should receive two doses of univalent varicella vaccine, at least 3 months apart.
Chronic renal disease/dialysis
Varicella vaccine is recommended for individuals with chronic renal disease or undergoing dialysis. Two doses of univalent varicella vaccine may be given, at least 3 months apart.
People with conditions such as autism spectrum disorders or demyelinating disorders (including multiple sclerosis) should receive all routinely recommended immunizations, including varicella-containing vaccine.
Although definitive data are lacking, individuals with autoimmune disease not being treated with immunosuppressive drugs are not considered significantly immunocompromised and should receive varicella immunization following consultation with a physician. The nature of the person’s underlying disease should be considered. Rheumatic disease modifying agents such as hydroxychloroquine, sulfasalazine, or auranofin are not considered immunosuppressive.
The safety and efficacy of live, attenuated vaccines during low dose intermittent or maintenance therapy with immunosuppressive drugs (other than corticosteroids) for autoimmune disease is unknown. These drugs include therapeutic monoclonal antibodies, especially the anti-tumour necrosis factor agents adalimumab, infliximab, and etanercept and others (azathioprine, methotrexate, leflunomide, and abatacept). These have been reported to cause reactivation of latent tuberculosis infection and predisposition to other opportunistic infections. Therefore, until additional information becomes available, avoidance of live vaccines during intermittent or low dose chemotherapy or other immunosuppressive therapy is prudent.
Refer to Immunization of Persons with Chronic Diseases in Part 3 for additional general information.
Consult with attending physician before vaccination.
If necessary, refer to a specialist with expertise in immunization and/or immunodeficiency. Refer to Immunocompromised persons.
Health care providers who see persons newly arrived in Canada should review the immunization status and update immunization for these individuals as necessary. People from tropical regions are more likely to be susceptible to varicella and should be a priority for varicella immunization. Refer to Immunization of Persons New to Canada in Part 3 for additional general information.
Varicella immunization should be offered to susceptible workers (refer to Susceptibility and immunity for a definition of susceptible) including health care workers, child care workers, and teachers of young children. These groups are at occupational risk of exposure or may transmit disease to susceptible individuals. For health care providers, a self-reported history of varicella is not reliable to be considered immune. A health care provider diagnosis of varicella or herpes zoster is required for immunity to be considered reliable based on clinical presentation. If a health care provider diagnosis is not available, serologic testing is required to document immunity. Two doses of varicella vaccine are recommended for susceptible workers as is the case for all susceptible adults. A second dose of varicella vaccine should be offered to workers who would have received only one dose of vaccine.
Health care workers with a post-vaccine rash at the injection site may continue to work if the rash is covered. Those with a varicella-like rash not confined to the injection site should be excluded from work in high-risk patient care areas (e.g., where there are premature infants and immunocompromised patients) until lesions are crusted. Vaccinees with a post-vaccination varicella-like rash rarely transmit the vaccine-associated virus.
Refer to Immunization of Workers in Part 3 for additional general information.
The following situations are significant exposures to VZV:
Univalent varicella vaccine given as soon as possible and within 3 and up to 5 days after exposure has been shown to be approximately 90% effective in preventing or reducing the severity of varicella and is the post-exposure management of choice for susceptible, healthy, non-pregnant persons. Varicella vaccination is not indicated for post-exposure management of infants less than 12 months of age, as the vaccine is not authorized for this age group and these infants are generally protected by maternal antibodies. Adults who previously received at least 1 dose of varicella-containing vaccine before 12 years of age or two doses thereafter should not be serologically tested as they are likely to be immune to varicella and commercially available antibody tests are usually not sensitive enough to detect post-vaccination antibody concentrations. Those who received only one dose of varicella-containing vaccine should be offered a second dose. There are no data on the use of MMRV vaccine in varicella post-exposure or outbreak situations.
The decision to administer VarIg should be based on fulfilling all of the following criteria:
If VarIg is being considered, consultation with an infectious diseases/infection control specialist is advised.
VarIg is of maximal benefit if administered within 96 hours after first exposure. However, since the exact timing of transmission is unknown, it may be used within 96 hours of the most recent exposure. If more than 96 hours have elapsed since the last exposure, the benefit of administering VarIg is uncertain. Protection conferred by VarIg lasts approximately 3 weeks. Subsequent exposures occurring more than 3 weeks after a dose of VarIg require additional doses of VarIg if the criteria for VarIg administration, as specified above, are met.
The recommended dose of VarIg is 125 IU/10 kg of body weight up to a maximum of 625 IU. The minimum dose is 125 IU. VarIg should be given by the intramuscular (IM) route. Intravenous administration is also possible in certain circumstances but is associated with additional safety considerations. For complete prescribing information, consult the product leaflet or information contained within Health Canada’s authorized product monographs available through the Drug Product Database. If VarIg is being considered, consultation with an infectious diseases/infection control specialist is advised.
Refer to Passive Immunization Part 5 for additional general information.
(12 months of ageTable 1 - Note ** and older)
|Pregnant||ImmunocompromisedTable 1 - Note ****|
|Vaccinate with varicella vaccine||Yes||No||No|
|Check VZV IgG||No||Yes||Yes|
|If VZV IgG negative, administer VarIgTable 1 - Note ***||Not applicable||Yes||Yes|
Post-exposure immunization is useful in preventing or limiting varicella outbreaks in hospitals, child care facilities and homeless shelters. Serologic testing for susceptibility is not necessary prior to immunization in an outbreak situation. There are no data on the use of MMRV vaccine in outbreak situations. Refer to Post-exposure immunization.
Each dose is 0.5 mL.
Univalent varicella vaccine should be administered subcutaneously (SC). Although the intramuscular (IM) route is not recommended, there is evidence that it is not necessary to repeat a dose of univalent varicella vaccine if it is inadvertently given IM. MMRV vaccine should be administered SC or IM. Refer to Vaccine Administration Practices in Part 1 for additional information.
Healthy children (12 months to 12 years of
For routine immunization of children aged 12 months to 12 years, two doses of varicella-containing vaccine (univalent varicella or MMRV) should be administered. The first varicella-containing vaccine dose should be administered at 12 to 15 months of age and the second dose at 18 months of age or any time thereafter. The recommended interval between two doses is at least 3 months, however a 6-week interval can be used if rapid complete protection is required. Two doses of varicella-containing vaccine (univalent varicella or MMRV) should be administered to children less than 13 years of age who were not routinely immunized with varicella-containing vaccine. The recommended interval between doses is at least 3 months. A minimum interval of 6 weeks between doses of varicella-containing vaccine may be used for catch-up immunization if rapid, complete protection is required. In deciding on the timing of the second dose, vaccine providers should consider factors such as the prevalence of varicella in the community, the current age of the child and attendance at a child care centre or school. The choice of vaccines and minimum interval for the second dose will depend on the vaccines and number of doses previously administered. Refer to Table 2 and Table 3. The minimum interval between doses of varicella-containing vaccines has been simplified and differs from previous NACI statements.
|Prior immunization||Recommended options for immunization|
| 0 dose MMR &
0 dose univalent varicella
| 2 doses MMRV (with the two doses at least 3 months
2 doses of MMRNote * and univalent varicellaNote * (with the two doses at least 3 months apartNote +)
| 1 dose MMR &
1 dose univalent varicella
| 1 dose MMRV (at least 3 months after
univalent varicellaNote +)
1 dose of MMRNote * and univalent varicellaNote * (at least 3 months after prior univalent varicellaNote +)
| 1 dose MMR &
0 dose univalent varicella
| 1 dose MMRV
(at least 6 weeks after the prior MMR), followed by 1 dose univalent
varicella (at least 3 months after MMRVNote +)
1 dose univalent varicella (at least 4 weeks after the prior MMR), followed by 1 dose MMRV (at least 3 months after univalent varicellaNote +)
| 2 doses MMR &
1 dose univalent varicella
|1 dose univalent varicella (at least 4 weeks after the last MMR AND at least 3 months after the prior univalent varicellaNote +)|
| 2 doses MMR &
0 dose univalent varicella
|2 doses univalent varicella (given at least 4 weeks after the last MMR, with a minimum interval of 3 months between the two doses of univalent varicellaNote +)|
| 1 dose MMRV &
0 dose univalent varicella
| 1 dose MMRV
(at least 3 months after the prior MMRVNote +)
1 dose each of MMRNote * and univalent varicellaNote * (at least 3 months after the prior MMRVNote +)
| 1 dose MMR &
1 dose MMRV
|1 dose of univalent varicella (at least 4 weeks after prior MMR or at least 3 months after the prior MMRVNote +)|
Adolescents (13-17 years of
Adolescents with unknown susceptibility status should be serologically tested for varicella antibodies because most will be immune. Healthy, varicella-susceptible adolescents should receive two doses of univalent varicella vaccine given at least 6 weeks apart.
Adults (18 years of
age and older)
Adults, under 50 years of age, with unknown susceptibility status should be serologically tested for varicella antibodies because most will be immune. Healthy, varicella-susceptible adults should receive two doses of univalent varicella vaccine administered at least 6 weeks apart. Refer to Recommendations for use.
In general, adults 50 years of age and older, are presumed to be immune to varicella. . Routine serology is not recommended in this age group. Herpes zoster vaccine is recommended in people 60 years of age and older without contraindications and may be used in people 50-59 years of age without contraindications. Refer to Herpes Zoster (Shingles) Vaccine in Part 4 for additional information.
|Healthy children 1-12 years of ageTable 3 - Note a||2 doses ≥ 3 months apartTable 3 - Note *|
|Healthy adolescents ≥ 13 years of age & adults||2 doses ≥ 6 weeks apart||No data, not recommended|
| Catch-up (unimmunized),
aged ≥ 12 months-12 years
|2 doses ≥ 3 monthsTable 3 - Note * apart|
| Post-exposure (unimmunized),
aged ≥ 12 months-12 years
|2 doses ≥ 3 months apartTable 3 - Note *||No data, not recommended|
| Select immunocompromised groups meeting prerequisites,
aged ≥ 12 months
|2 doses ≥ 3 months apart||No data, not recommended|
| At least 2 years post-HSCT,
aged ≥ 12 months
|1 dose (no data for 2 doses)||No data, not recommended|
Re-immunization with varicella-containing vaccine after age and risk appropriate vaccination is not necessary. Herpes zoster vaccine is recommended for persons 60 years of age and older without contraindications and may be used in persons 50 to 59 years of age without contraindications Refer to Herpes Zoster (Shingles) Vaccine in Part 4 for additional information.
Serologic testing is not recommended in children (12 months to 12 years of age) before receiving a varicella-containing vaccine. In adolescents and adults (13 to less than 50 years of age) who may be susceptible to varicella (refer to Susceptibility and immunity for a definition of susceptible) serologic testing should be performed before immunization as the majority of such individuals will be immune and will not require varicella vaccine. Individuals 50 years of age and over are presumed to be immune unless known to be varicella-susceptible based on serology previously drawn for other purposes. Routine serology is not recommended in this age group.
Serologic testing is not recommended for healthy children. Previously vaccinated individuals who are inadvertently tested are likely to be immune to varicella even if there is no detectable antibody. Commercially available varicella antibody tests, such as the enzyme-linked immunosorbant assay (ELISA) and latex agglutination (LA), may not have sufficient sensitivity to detect antibody after vaccination, although they are useful for establishing immunity after wild-type infection. Immunocompromised people who are vaccinated with univalent varicella vaccine may have antibody testing performed 6 to 8 weeks after the last dose (refer to Figure 1). However, local antibody tests may not be sensitive enough to detect antibody after immunization. The glycoprotein ELISA (gpELISA) test is more sensitive, but is not routinely available.
VARILRIX®: Store the vaccine in a refrigerator at +2°C to +8°C. The diluent may be stored in the refrigerator or at ambient temperature (maximum +25ºC). The freeze-dried vaccine is not affected by freezing.
VARIVAX® III: Store the vaccine at +2°C to +8°C or colder. The vaccine may be stored in a freezer at temperatures less than -50°C; if subsequently transferred to a refrigerator, the vaccine should not be refrozen. Protect from light. The vial of diluent should be stored separately at room temperature (+20°C to +25°C) or in the refrigerator (+2°C to +8°C).
PRIORIX-TETRA®: Store the vaccine and diluent in a refrigerator at +2°C to +8°C and do not freeze. Protect the vaccine from light.
Refer to Storage and Handling of Immunizing Agents in Part 1 for additional general information. Refer to Passive Immunization Part 5 for information regarding VarIg storage requirements.
Varicella-containing vaccine may be administered concomitantly with routine childhood vaccines or live intranasal influenza vaccine (LAIV). Different injection sites and separate needles and syringes must be used for concomitant parenteral injections. If not given concomitantly, a minimum interval of 4 weeks is recommended between administration of two live vaccines. These recommendations are to address the hypothetical risk of interference from the vaccine given first on the vaccine given later. Recommended intervals between varicella-containing vaccines are provided in Table 3. Refer to Timing of Vaccine Administration in Part 1 for additional general information.
Refer to Vaccine Safety and Adverse Events Following Immunization Part 2 for additional general information.
Reactions to univalent varicella vaccine are generally mild and include injection site pain, swelling and redness in 10% to 20% of recipients. A low-grade fever has been documented in 10% to 15% of vaccinees. A varicella-like rash occurs at the injection site or is generalized in 3% to 5% of vaccinees after the first dose and 1% after a second dose. The rash usually appears within 5 to 26 days after immunization. As varicella-like rashes that occur within the first two weeks after immunization may be caused by wild-type virus, health care providers should obtain specimens from the vaccinee to ensure varicella disease is not confused with a reaction to vaccination.
The safety profile of a 2-dose regimen is comparable to that of a single dose: the incidence of injection site reactions observed within 3 days after vaccination was slightly higher after dose 2 (25.4%) than after dose 1 (21.7%), while fever incidence (which can occur 7 to 21 days after receipt of vaccine) was 7% after dose 1 and 4% after dose 2, and varicella-like rash incidence after dose 1 was 3%, compared with 1% after dose 2. Febrile seizures should be reported following varicella-containing vaccines.
Pain and redness at the injection site and/or low-grade fever occur in 10% or more of vaccinees. Rash, including measles-like, rubella-like and varicella-like rash, as well as swelling at the injection site and moderate fever (greater than 39°C), occur in 1% to less than 10% of vaccinees. As varicella-like rashes that occur within the first two weeks after immunization may be caused by wild-type virus, health care providers should obtain specimens from the vaccinee to ensure varicella disease is not confused with a reaction to vaccination.
Reactions to VarIg are rare. The most frequent treatment related adverse events are pain at the injection site (17%), headache (7%), and rash (5%).
Acute transient arthritis or arthralgia may occur 1 to 3 weeks after immunization with rubella-containing vaccine, such as MMRV. It lasts for about 1 to 3 weeks, and rarely recurs. This is more common in post-pubertal females, among whom arthralgia develops in 25% and arthritis in 10% after immunization with rubella-containing vaccine. There is no evidence of increased risk of new onset, chronic arthropathies or neurologic conditions.
Serious adverse events are rare following immunization and, in most cases, data are insufficient to determine a causal association. Anaphylaxis following vaccination with varicella-containing vaccine may occur but is very rare.
Most reported serious adverse events have not been proven to be caused by the vaccine, with the exception of rare events linked to the varicella vaccine strain among immunocompromised individuals or those with other serious medical conditions.
Immune Thrombocytopenic Purpura (ITP)
Rarely, ITP occurs within 6 weeks after immunization with MMRV vaccine. In most children, post-immunization thrombocytopenia resolves within three months without serious complications. In individuals who experienced ITP with the first dose of MMRV vaccine, serologic status may be evaluated to determine whether an additional dose of vaccine is needed. The potential risk to benefit ratio should be carefully evaluated before considering vaccination in such cases.
Encephalitis has been reported in association with administration of measles vaccine in approximately 1 per million doses distributed in North America which is much lower than that observed with natural measles disease (1 per 1,000 cases).
Recent studies have found a higher risk of febrile seizures with the first dose of a MMRV vaccine (ProQuad®, Merck, not authorized for use in Canada) when compared to the concomitant administration of MMR and univalent varicella vaccine. Data from the US estimated that the risk of febrile seizures in the 5 to 12 days following the first dose of this MMRV vaccine is 1 for every 2,600 vaccinated children aged 12 to 23 months. Experience with the MMRV vaccine available in Canada is more limited; however, one study showed a statistically non-significant increased risk of febrile seizures with MMRV vaccine compared to MMR and varicella given as two separate vaccines administered concomitantly. Close surveillance and further investigation are underway.
There is a remote risk of an anaphylactic reaction to VarIg in individuals with hypersensitivity to blood products.
Herpes zoster has been reported after varicella immunization due to reactivation of either the vaccine or wild-type strain. The risk of herpes zoster developing is 4-fold to 12-fold lower in vaccinated as compared with unvaccinated children under 10 years of age. The risk of herpes zoster after vaccination with MMRV vaccine is unknown.
Transmission of vaccine strain virus from a healthy vaccinee is very rare. There have been few documented cases, all associated with a rash in the vaccinee.
Vaccine providers are asked to report the following AEFI in particular, through local public health officials:
Refer to Box 1 Vaccine Safety in Part 2 and the Report of Adverse Events Following Immunization (AEFI) User Guide for additional information about AEFI reporting.
Varicella-containing vaccines and VarIg are contraindicated in persons with a history of anaphylaxis after previous administration of the product and in persons with proven immediate or anaphylactic hypersensitivity to any component of the product (with the exception of egg allergy for MMRV vaccine [see below]) or its container. Refer to Table 1 and Table 2 in General Considerations in Part 1 for lists of all vaccines and passive immunization available in Canada and their contents. For varicella-containing vaccines, potential allergens include:
In situations of suspected hypersensitivity or non-anaphylactic allergy to vaccine components, investigation is indicated which may involve immunization in a controlled setting. Consultation with an allergist is advised.
The measles and mumps components of MMRV vaccine are produced in chick embryo cell culture and may contain traces of egg protein. The amount of egg protein in the vaccine appears to be insufficient to cause an allergic reaction in egg-allergic individuals. Skin testing is not recommended prior to vaccination. MMRV vaccine can be administered in the routine manner to people who have a history of anaphylactic hypersensitivity to hens’ eggs. Prior egg ingestion is not a prerequisite for immunization. For all vaccines, immunization should be performed by personnel with the capability and facilities to manage adverse events post-vaccination. Refer to Anaphylactic Hypersensitivity to Egg and Egg-Related Antigens in Part 2 for additional information.
Children with a known or suspected family history of congenital or hereditary immunodeficiency that is a contraindication to vaccination with live vaccine should not receive live vaccines unless their immune competence has been established.
MMRV vaccine is contraindicated in persons with impaired immune function, including primary or secondary immunodeficiency disorders. Vaccination with univalent varicella vaccine may be considered in select disorders. Refer to Immunocompromised persons.
Varicella-containing vaccines are contraindicated during pregnancy. Refer to Pregnancy and lactation.
VARIVAX® III is contraindicated in individuals with active, untreated tuberculosis. Initiating anti-turberculous therapy is advisable before administering varicella-containing vaccines. Tuberculosis may be exacerbated by natural measles infection. However, there is no evidence that measles-containing vaccine such as MMRV has such an effect.
A history of febrile seizures or a family history of seizures is not a contraindication for the use of MMRV vaccine.
Administration of varicella-containing vaccine should be postponed in persons with moderate or severe acute illness and should be delayed by at least 4 weeks (ideally 6 weeks, if feasible) following measles infection. Persons with minor acute illness (with or without fever) may be vaccinated.
Following MMRV vaccine, transmission of measles, mumps and rubella vaccine viruses from vaccinees to susceptible contacts has not been documented and transmission of varicella vaccine virus may occur very rarely between healthy vaccinees who develop a varicella-like rash and susceptible contacts.
It is recommended to avoid the use of salicylates for 6 weeks after immunization with varicella-containing vaccine. Refer to Drug Interactions.
Persons with specific immunoglobulin A (IgA) deficiency have increased potential for developing antibodies to IgA after receipt of blood products including VarIg and could have anaphylactic reactions to subsequent administration of blood products containing IgA, such as VarIg.
Refer to General Contraindications and Precautions in Part 2 and Passive Immunization Part 5 for additional general information.
Systemic antiviral therapy (such as acyclovir, valacyclovir, famciclovir) should be avoided in the peri-immunization period, as it may reduce the efficacy of varicella-containing vaccine. On the basis of expert opinion, it is recommended that people taking long-term antiviral therapy should discontinue these drugs, if possible, from at least 24 hours before administration of varicella-containing vaccine and should not restart antiviral therapy until 14 days after.
The measles component in MMRV vaccine can temporarily suppress tuberculin reactivity, resulting in false-negative results. The effect of other live virus vaccines, such as univalent varicella vaccine on tuberculin reactivity is unknown. Until data are available, if tuberculin skin testing or an Interferon Gamma Release Assay (IGRA) is required, it should be done on the same day as immunization or delayed for at least 4 weeks after varicella vaccination. Vaccination with measles and/or varicella-containing vaccine may take place at any time after tuberculin skin testing has been performed and read.
Varicella-containing vaccine manufacturers recommend avoidance of salicylate therapy (medications derived from salicylic acid, e.g., acetylsalicylic acid [ASA]) for 6 weeks after varicella immunization because of an association between wild-type varicella, salicylate therapy and Reye’s syndrome. Health care providers should weigh the theoretical risks associated with varicella vaccine against the known risks associated with wild-type varicella infection. Because adverse events have not been reported with the use of salicylates after varicella immunization, people with conditions requiring chronic salicylate therapy should be considered for immunization, with close subsequent monitoring.
Passive immunization with human immune globulin or receipt of most blood products can interfere with the immune response to varicella-containing vaccine. These vaccines should be given at least 14 days prior to administration of an immune globulin preparation or blood product or delayed until the antibodies in the immune globulin preparation or blood product have degraded. If the interval between administration of vaccine and subsequent administration of an immune globulin preparation or blood product is less than 14 days, immunization should be repeated. The recommended interval between administration of an immune globulin preparation or blood product and subsequent immunization with a live vaccine such as varicella varies, depending on the immune globulin preparation or blood product. Palivizumab (RSVAb) and washed red blood cell transfusion do not interfere with the antibody response to varicella-containing vaccines. Refer to Recent Administration of Human Immune Globulin Products in Part 1 for additional general information.
Virus identification from clinical specimens (e.g., vesicle scraping) by laboratory methods in order to differentiate wild type from vaccine-derived VZV should be considered when:
Polymerase chain reaction testing to differentiate vaccine-derived from wild type varicella virus can be performed by the National Microbiology Laboratory in Winnipeg.
For a two-dose schedule, it is recommended that the same manufacturer’s univalent varicella vaccine or MMRV vaccine be used to complete the schedule unless there are unavoidable barriers (e.g., the vaccine used for the first dose is not available). Refer to Principles of Vaccine Interchangeability in Part 1 for additional general information.