Two vaccines containing varicella virus are licensed for use in the United States. Both vaccines contain live, attenuated varicella zoster virus (VZV) derived from the Oka strain.
- Varivax (VAR, Merck) contains only varicella vaccine virus.
- ProQuad (MMRV, Merck) is a combination measles, mumps, rubella, and varicella vaccine
Both vaccines may be administered either by subcutaneous injection or intramuscular injection. VAR is approved by the Food and Drug Administration (FDA) for people 12 months of age and older. MMRV is approved for people 12 months through 12 years of age. MMRV should not be administered to people age 13 years or older.
Last reviewed:
May 16, 2023
All children, beginning at age 12 months, as well as adults without other evidence of immunity should be vaccinated with 2 doses of varicella vaccine. Special consideration should be given to vaccinating adults who (1) have close contact with people at high risk for severe disease (e.g., healthcare workers and family contacts of immunocompromised people), or (2) are at high risk for exposure or transmission (e.g., teachers of young children; child care employees; residents and staff members of institutional settings, including correctional institutions; college students; military personnel; adolescents and adults living in households with children; non-pregnant women of childbearing age; and international travelers).
Last reviewed:
May 16, 2023
The Advisory Committee on Immunization Practices (ACIP) considers evidence of immunity to varicella to be:
- Written documentation of 2 doses of varicella vaccine given no earlier than age 12 months with at least 4 weeks between doses.
- U.S.-born before 1980*
- A healthcare provider’s diagnosis of varicella or verification of history of varicella disease
- History of herpes zoster, based on healthcare provider diagnosis or verification of disease history
- Laboratory evidence of immunity or laboratory confirmation of disease
*Note: Although there is only a very small chance of susceptibility, due to the potential for severe consequences from varicella infection, year of birth is not accepted as evidence of varicella immunity for healthcare personnel, immunosuppressed people, and pregnant people.
Last reviewed:
May 16, 2023
No. ACIP recommends giving a dose of MMR to infants age 6 through 11 months before international travel, but not varicella vaccine. Varicella vaccine is neither approved nor recommended for children younger than age 12 months in any situation.
Last reviewed:
May 16, 2023
Varicella vaccine is neither approved nor recommended for children younger than age 12 months. Assuming that the child is not immunocompromised, varicella zoster immune globulin (VariZIG) is also not recommended.
ACIP does not have a recommendation for acyclovir for varicella postexposure prophylaxis. The American Academy of Pediatrics provide some guidance on this issue in the current edition of the Red Book.
Last reviewed:
May 16, 2023
No. A healthcare provider’s diagnosis or verification of a history of shingles is acceptable evidence of immunity to varicella. According to ACIP, acceptable evidence of varicella immunity in healthcare personnel includes (1) documentation of 2 doses of varicella vaccine given at least 28 days apart, (2) history of varicella or herpes zoster based on clinician diagnosis, (3) laboratory evidence of immunity, or (4) laboratory confirmation of disease.
Last reviewed:
May 16, 2023
Recombinant zoster vaccine (RZV, Shingrix, GSK) does not count as the first of two doses of varicella vaccine. Shingrix is not licensed and has not been evaluated for the prevention of primary varicella infection. To meet the immigration requirements, you should give a dose of varicella vaccine now and a second dose at least 4 weeks later. The varicella vaccine doses will not be harmful and will allow your patient to meet the regulatory requirement.
Last reviewed:
May 16, 2023
Yes. For everyone whose varicella immunity is based on vaccination, 2 doses of varicella vaccine are recommended.
Last reviewed:
May 16, 2023
In the ten years following vaccine licensure in 1995, there was a significant decline in varicella disease, as well as varicella-related hospitalizations and deaths. Although a 1-dose regimen was estimated to be 80% to 85% effective, breakthrough disease was still occurring in highly vaccinated populations. A 2-dose regimen was adopted in 2006 to further reduce the risk of disease among vaccinated people whose numbers would accumulate over time, which could lead to varicella disease later in life when it can be more severe.
Last reviewed:
May 16, 2023
If the child had confirmed varicella disease or laboratory evidence of prior disease, it is not necessary to vaccinate regardless of age at infection. If there is any doubt that the illness was actually varicella, the child should be vaccinated.
Last reviewed:
May 16, 2023
It is critical to vaccinate susceptible older children and adults whenever the opportunity arises. With younger children being routinely vaccinated, the chance of being exposed to cases of chickenpox is decreasing. Older children, adolescents, and adults who have not had chickenpox now have a greater chance of remaining susceptible. These older individuals, when they contract chickenpox, are more likely to become seriously ill and have disease complications than younger children.
Last reviewed:
May 16, 2023
No. Shingles is caused by varicella zoster virus, the same virus that causes chickenpox. A history of shingles based on a healthcare provider diagnosis is evidence of immunity to chickenpox. A person who has had shingles does not need to be vaccinated against varicella. The person should still receive zoster vaccine, however, if it is not contraindicated and the person is age 50 or older or is age 19 or older and immunocompromised.
Last reviewed:
May 16, 2023
No. Receipt of one dose of live zoster vaccine is not proof of varicella immunity. According to CDC, acceptable evidence of varicella immunity in healthcare personnel includes (1) documentation of 2 doses of varicella vaccine given at least 28 days apart, (2) history of varicella or herpes zoster based on clinician diagnosis, (3) laboratory evidence of immunity, or (4) laboratory confirmation of disease. If a healthcare employee has received a dose of live zoster vaccine in the past but has no other evidence of immunity to varicella, the live zoster dose can be considered the first dose of the 2-dose varicella series. Note that recombinant zoster vaccine (RZV, Shingrix) cannot be counted as the first dose in a 2-dose varicella vaccination series because Shingrix is not licensed and has not been evaluated for the prevention of primary varicella infection (chickenpox).
Last reviewed:
May 16, 2023
Yes. In its 2018 recommendations for the prevention of herpes zoster, ACIP states that Shingrix may be used in adults age 50 years or older irrespective of prior receipt of varicella vaccine or live zoster vaccine (Zostavax, Merck). Shingrix is also recommended for adults age 19 and older who are immunocompromised due to disease or treatment if they have a history of varicella illness or vaccination.
Last reviewed:
May 16, 2023
A mild case of chickenpox produces immunity to varicella as does a moderate or severe case. A child with a reliable history of chickenpox does not need to receive varicella vaccine. However, if there is any doubt that the mild illness really was chickenpox, it is best to vaccinate the child. There is no harm in vaccinating a child who is already immune.
Last reviewed:
May 16, 2023
Varicella vaccine is most effective in preventing chickenpox or reducing the severity of the disease if used within 72 hours (3 days), and may still be helpful up to 5 days after exposure. However, not every exposure to varicella leads to infection, so for future immunity, varicella vaccine should be given to a person age 12 months or older who does not have a contraindication to vaccination, even if more than 5 days have passed since an exposure.
Last reviewed:
May 16, 2023
The only way to determine whether the rash is caused by wild-type varicella or vaccine virus is to try to isolate virus from the rash and send it to a laboratory that is capable of differentiating wild and vaccine-type virus. This is generally not practical. Given the history, the conservative approach is to assume she has an active case of chickenpox and act according to your infection control guidelines.
Last reviewed:
May 16, 2023
There is currently no information on the effect of varicella vaccine on reactivity to a tuberculin skin test (TST). Until information is available, it is prudent to apply the same rules to varicella vaccine as are applied to MMR: a TST (i.e., PPD) may be applied before (preferably) or simultaneously with varicella vaccine. If vaccine has been given, delay the TST for at least 4 weeks.
Last reviewed:
May 16, 2023
Live varicella vaccine should not be given to anyone known to be pregnant. If a person who is planning to become pregnant in the future comes in for a visit or an annual exam, the varicella history should be obtained and if indicated, 2 doses of vaccine should be given, spaced 4 to 8 weeks apart. Vaccine recipients capable of becoming pregnant should be counseled to avoid pregnancy for one month following each dose of varicella vaccine. A person who is inadvertently vaccinated while pregnant or becomes pregnant within a month of vaccination should be counseled about the theoretical risk to the fetus; however, it should not be considered a reason to terminate a pregnancy. Pregnant people should be assessed for evidence of varicella immunity and if non-immune, should receive the first dose of varicella vaccine following completion of the pregnancy and prior to hospital discharge. A second dose should be given 4 to 8 weeks later.
Last reviewed:
May 16, 2023
People with a reliable history of varicella can be considered to be immune. A reliable history for healthcare personnel consists of (1) a healthcare provider’s diagnosis of varicella or verification of history of varicella disease; (2) a healthcare provider’s diagnosis of herpes zoster or verification of a history of herpes zoster; or (3) laboratory evidence of immunity or laboratory confirmation of disease. Immunity following disease or vaccination is probably life-long. More than one primary infection with varicella is unusual.
Last reviewed:
May 16, 2023
No. Serologic testing for varicella should be considered only for pregnant people who do not have evidence of immunity (reliable history of chickenpox or documented vaccination). Once a person has been found to be seropositive, it is not necessary to test again in the future.
Last reviewed:
May 16, 2023
Contrary to the information provided in the vaccine package insert, which states that pregnancy should be avoided for 3 months, the ACIP recommends that a wait of 1 month is sufficient.
Last reviewed:
May 16, 2023
To date, no adverse outcomes of pregnancy or in a fetus have been reported among people who inadvertently received varicella vaccine shortly before or during pregnancy. The risk of congenital varicella syndrome following varicella disease is small, so the risk of congenital anomalies following vaccination with live attenuated varicella zoster virus (VZV)-containing vaccine is probably very small.
Merck and the Centers for Disease Control and Prevention (CDC) jointly operated a pregnancy registry for women exposed to VZV-containing vaccines for seventeen years after the licensure of varicella vaccine. The registry was discontinued in 2013, having found no signals to indicate a risk of Congenital Varicella Syndrome or pattern of birth defects related to vaccination with VZV-containing vaccines. Healthcare providers may continue to report exposure to VZV-containing vaccines within 3 months of conception or during pregnancy by contacting Merck’s call center at 1-877-888-4231.
Last reviewed:
May 16, 2023
