VACCINE RESOURCE COMMITTEE

of the Edmonton Zone Medical Staff Association

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measles, mumps, rubella and varicella Vaccine Question #4:

Does the vaccine lose effectiveness over time?

More data is needed regarding the long-term effectiveness of MMRV vaccine to protect against varicella as
it was first approved in 1999.

Between 1970 to 1996 one dose of the MMR (measles, mumps and rubella) vaccine was recommended. As of 1996 two doses became the standard. Many people immunized before 1996 have not got a second dose.

Protection with two doses of the vaccine is:

  • 100% for measles

  • 76% to 95% for mumps

  • 95% for rubella

  • 98% for varicella

Measles

Both serologic and epidemiologic evidence indicate that vaccine-induced measles immunity appears to be long-term and probably lifelong in most persons.

Mumps

While the effectiveness of two doses of MMR against mumps is high, serologic and epidemiologic studies suggest this effectiveness decreases with time. A person with a decreased immune response after time may then become infected when exposed to mumps virus through close contact with a person with mumps. A third dose of MMR can provide added short term protection for those who are likely to have close contact with a mumps patient during an outbreak.

Rubella

Studies indicate that one dose of vaccine confers long-term, probably lifelong, protection against rubella.

Varicella

The National Immunization Advisory Committee (NACI) first recommended universal varicella vaccination for Canada in 1999. By 2005 all the provinces and territories had vaccination program.

The rate of breakthrough varicella disease in vaccine recipients following 1 dose of univalent varicella vaccine has been estimated at 7.2% over a 10 year follow-up period. A 2 dose primary schedule for children 12 months to 12 years of age has shown to reduce the cumulative risk of breakthrough disease 3.3-fold compared to children who received only 1 dose. The estimated vaccine effectiveness 10 years following the receipt of 2 doses of univalent varicella vaccine is estimated at over 98% against any varicella disease and 100% against severe varicella.

There are no data regarding the long-term effectiveness of MMRV vaccine for varicella.

  • Several studies have shown that people vaccinated against varicella had antibodies for at least 10 to 20 years after vaccination. But, these studies were done before the vaccine was widely used and when infection with wild-type varicella was still very common.

  • A case-control study conducted from 1997 to 2003 showed that 1 dose of varicella vaccine was 97% effective in the first year after vaccination and 86% effective in the second year. From the second to eighth year after vaccination, the vaccine effectiveness remained stable at 81 to 86%. Most vaccinated children who developed varicella during the 8 years after vaccination had mild disease.

  • A clinical trial showed that children with 2 doses of varicella vaccine were protected 10 years after being vaccinated. Fewer people had breakthrough varicella after 2 doses compared with 1 dose. The risk of breakthrough varicella did not increase over time.

  • A meta-analysis that included 1-dose vaccine effectiveness reported through 2015 found a pooled estimate of 82% within the first decade. Considering the age of participants in the studies and vaccine recommendations in each country, the median time since vaccination is likely lower than 10 years. Four studies reported decline in VE with time since vaccination; however, the differences did not reach statistical significance.

  • Two doses of varicella vaccine add improved protection, with a pooled estimate of 92% (assessed ~5 years after vaccination).

Sources:

Alberta Health Services: Measles, mumps, rubella, varicella (MMR-Var) vaccine
CDC: Vaccines & Immunizations: About the Vaccine
Government of Canada: Varicella (chickenpox) vaccines: Canadian Immunization Guide
CDC: Vaccines & Immunizations: About the Varicella Vaccine