VACCINE RESOURCE COMMITTEE
of the Edmonton Zone Medical Staff Association
View Full List of Vaccine Questions Here
measles, mumps, rubella and varicella Vaccine Question #2:
Is there still a risk for measles, mumps, rubella and chickenpox?
Yes. For example measles has recently resurged in Canada. Maintaining a high population vaccine coverage rate retains community immunity; thus, reducing outbreaks.
High population vaccination rates protect from virus risk with community immunity
High rates of vaccine uptake in the community reduce the risk of outbreaks. The more people who are vaccinated in the community, the lower the risk of infection for those who:
can't be vaccinated
are too young to receive vaccines (infants)
developed only partial immunity from the vaccine
The Government of Canada goal for 2025 is 95% of children age two with their first dose and children age seven with two doses of the MMR-Var or MMR vaccine.
As of 2023, Alberta had only 69% of the whole population immunized with two doses by age 2; therefore, the community is vulnerable to outbreaks and viruses resurging in Alberta. Some locations are low, such as:
High Level with 11%
Two Hills County with 25%
County of Forty Mile 27%
Taber Md with 28%
Wabasca with 30%
Vaccine recommendation history
If born before 1970, an adult likely does not need this vaccine. That is because there is a high chance of immunity from contact with with the viruses when younger.
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.
In Alberta, the MMR-Var vaccine became available in September 2010. Now, both MMR and MMR-Var (measles, mumps, rubella and varicella) vaccines are available. The Varilrix vaccine is publicly funded for people 13 and older. MMR-Var is on label, available and publicly funded for people up to age 12. MMR may also be used for older adults who need to update their MMR immunity but who are already immune to varicella. During outbreaks MMR might be used for very young infants.
Protection with two doses of the vaccine is:
100% for measles
76% to 95% for mumps
95% for rubella
98% for varicella
Measles
Measles was eradicated in Canada in 1988 due to vaccination, but has returned because vaccination rates are low and travel. There is a current outbreak with daily cases reported here.
Measles is nationally notifiable. Before vaccinations, about 10,000 to 90,000 people living in Canada were infected with measles every year. Since the introduction of the measles vaccine in Canada, measles cases have decreased by more than 99% (Figure 1).
Number and incidence rates (per 100,000 population) of reported measles cases in Canada by year, 1924 to 2023
Source: Government of Alberta: Measles: For health professionals
Mumps
Since the approval of mumps vaccine in 1969, the number of reported mumps cases has decreased by more than 99%. With the introduction of routine immunization programs, cases of mumps have become sporadic and are often associated with outbreaks.
Reported cases and incidence (per 100,000 person-years) of mumps in Canada by year, 1924 to 2013
Source: Government of Canada: Mumps: For Health Professionals
During outbreaks, people who previously had one or two doses of MMR vaccine can still get mumps. Experts aren't sure why vaccinated people still get mumps, but some evidence suggests that:
Some people's immune systems may not respond as well as they should to the vaccine.
The mumps vaccine may produce antibodies (proteins created by the body's immune system to help fight infections) that are not as effective against wild-type virus strains.
In some people, antibodies from mumps vaccination may decrease overtime, until they no longer protect the person from mumps.
As most people are not routinely exposed to mumps, there is less immunologic boosting (where people are exposed to mumps which boosts their immunity, but they do not get sick).
Disease symptoms are milder and complications are less frequent in vaccinated people. High vaccination coverage also helps to limit the size, duration, and spread of mumps outbreaks. So, it's still very important to be up to date on MMR vaccine.
During a mumps outbreak, public health authorities might recommend an additional dose of MMR vaccine for people who belong to groups at increased risk for getting mumps. These groups are usually those who are likely to have close contact, such as sharing sport equipment or drinks, kissing, or living in close quarters, with a person who has mumps.
Rubella
In Canada, routine infant immunization programs have resulted in sustained high rates of immunity to the rubella virus. These programs have also helped to eliminate the transmission of congenital rubella infection. Congenital rubella syndrome is a primary infection transmitted from the mother to the fetus during pregnancy.
Reported cases and incidence (per 100,000 population) of rubella in Canada, 1924 to 2014
Source: Government of Canada: Surveillance of rubella
Varicella
In the pre-vaccine era, approximately 350,000 varicella cases were estimated to occur each year in Canada. However, assessing the effect of varicella immunization programs on the incidence of varicella is difficult because varicella infections are significantly under-reported, less than 10% of the expected cases being reported.
A review of data from the Canadian Institute for Health Information for 1994 to 2000 showed that over 1,550 varicella hospitalizations occur annually for all age groups. For the most recent period, 1999 to 2009, a total of 2,297 pediatric varicella related hospitalizations were reported from 12 sites across Canada, averaging 208 hospitalizations annually for children age up to 16. Among these cases, children at pre-school ages were affected mostly and accounted for 14% (age < 1) and 66% (age 1-6) of the total hospitalizations, respectively. Since the public funded vaccine programs began in 2004 in Canada, the annual hospitalizations of varicella dropped from 288 (1999 to 2004) to 114 (2005-2009).
Sources:
Alberta Health Services: Measles, Mumps, Rubella and Varicella Vaccine
Government of Canada: Vaccination Coverage Goals and Vaccine Preventable Disease Reduction Targets by 2025
Government of Canada: Adult National Immunization Coverage Survey (aNICS): 2023 results
Government of Alberta: Interactive Health Data Application
Alberta Health Services: Measles, mumps, rubella, varicella (MMR-Var) vaccine
Government of Alberta: Measles
Alberta Health Services: Measles
Government of Canada: Measles and rubella weekly monitoring reports
Government of Canada: Measles: For health professionals
Government of Canada: Mumps: For health professionals
Government of Canada: Surveillance of rubella