Measles - Natural Immunity and Adult Vaccination

Public health officials (yes, the same ones that promoted COVID-19 vaccines) are now on to their next viral "boogeyman", measles.  As background, like many people particularly baby boomers, when I was younger, I had both red/hard measles also known as rubeola and German measles also known as rubella.  Given the recent advice being offered by public health officials that ALL people should be vaccinated against measles, I wondered if there were any studies that compared vaccine-induced immunity to measles to natural immunity among the vast community of adults who have already had one or both types of measles.

 

Let's start with this announcement from Canada's  Chief Public Health Officer, Teresa Tam:

 

 

Note the following recommendations:

 

1.) I strongly advise everyone in Canada to be vaccinated with two doses of a measles vaccine, especially before travelling.

 

2.) Adults should ensure they have received two doses of a measles-containing vaccine if they were born in 1970 or later, and one dose of a measles-containing vaccine if born before 1970.

 

Notice that Canada's Chief Public Health Officer states absolutely nothing about natural immunity conferring protection from measles, particularly for adults born prior to 1970.

 

According to the Centers for Disease Control and Prevention, the following  vaccination recommendation applies for adults:

 

"People who are born during or after 1957 who do not have evidence of immunity against measles should get at least one dose of MMR vaccine."

 

Evidence of immunity is defined as follows:

 

"Acceptable presumptive evidence of immunity against measles includes at least one of the following:

 

1.) written documentation of adequate vaccination

 

a.) one or more doses of a measles-containing vaccine administered on or after the first birthday for preschool-age children and adults not at high risk

 

b.) two doses of measles-containing vaccine for school-age children and adults at high risk, including college students, healthcare personnel, and international traveler

 

2.) laboratory evidence of immunity

 

3.) laboratory confirmation of measles

 

4.) birth before 1957"

 

Note that the CDC is using a 1957 birth year and that Canada's CPHO is using a 1970 birth year.  It is also interesting to observe that, unlike Canada's Chief Public Health Officer who advises that all Canadians should be vaccinated,  the CDC has an extensive list of people who should NOT get the MMR vaccine:

If adults who were born during or after 1957 plan to travel internationally, these are the CDC's recommendations:

 

"Teenagers and adults born during or after 1957 without evidence of immunity against measles should have documentation of two doses of MMR vaccine, with the second dose administered no earlier than 28 days after the first dose."

 

Here's another quote from the CDC in a March 2024 update:

 

"Measles is so contagious that if one person has it, up to 90% of the people close to them can also become infected if they are not protected by vaccination (or, less commonly, prior infection)."

 

Here is a listing of MMR and MMRV (measles, mumps, rubella and varicella) vaccines used in the United States from the CDC:

 

1.) M-M-R II® is a combination measles, mumps, and rubella (MMR) vaccine manufactured by Merck & Co, Inc.

2.) PRIORIX® is a combination measles, mumps, and rubella (MMR) vaccine manufactured by GlaxoSmithKline Biologicals (GSK).

3.) ProQuad® is a combination measles, mumps, rubella, and varicella (MMRV) vaccine manufactured by Merck & Co, Inc.

The CDC states that both serologic and epidemiologic evidence indicate that vaccine-induced measles immunity appears to be long-term and probably lifelong in most persons.  Studies indicate that one dose of vaccine confers long-term, probably lifelong, protection against rubella.

 

Now, let's look at a study which compares long-term immunogenicity after measles vaccine versus infection with the measles virus which appears on the National Institutes for Health National Library of Medicine website:

 

The authors of the Italian study used 611 subjects, both students and residents of the Medical School of the University of Bari and tested their immunogenicity (IgG) to measles, dividing them into two groups; those vaccinated with two doses of an anti-MMR vaccine (measles, mumps and rubella) and those who had a self-reported history of measles infection.  In Italy, the measles vaccine protocol was introduced in the 1970s with two doses of MMR live virus vaccine being recommended in 2003 with the first dose at 12 to 15 months of age and the second at 5 to 6 years of age.

 

For each subject, a 5 mL serum sample was collected to assess the immunity and susceptibility status.  Vaccinated individuals who had a non-protective immunogenicity (IgG) titre received an MMR vaccine with a second blood test being performed 20 to 25 days later to measure the IgG titre.  If the value did not exceed the cutoff, the individual was classified as non-seroconverted and a second vaccine dose was administered 28 days after the first booster.

 

The authors observed the following with my bolds:

 

1.) Although the immune responses induced by the vaccine are qualitatively similar to those induced by infection, antibody levels are lower after vaccination. Vaccination at a young age enhances the quality and quantity of the antibody response but has a minor effect on T cell responses. However, over time, virus-specific antibodies and vaccine-induced CD4 + T cells decrease, accounting for the secondary vaccine failure rate of 5% 10–15 years after immunization.

 

2.) The authors assessed each subject's protective antibody survival or PAS which is defined as the time elapsed from the second dose of routine MMR vaccine to the evaluation of antibody titer (years) or the time elapsed between natural measles infection to the evaluation of antibody titer (years).  They found the following:

 

"The group that had been infected by the wild virus have far longer protective antibody survival to measles than those who receive the measles vaccine."

Here is a graphic which shows the results of their analysis:

3.) "While further research is needed, our study clearly showed that natural immunity is both more robust and longer-lasting than vaccine immunity. However, this finding should not lead to a questioning of the role of measles vaccination."

Let's close with this data from the CDC showing how measles vaccine effectiveness is quite widely variable as follows:

 

One dose - 1 dose of MMR vaccine is—

93% effective for measles (range: 39%–100%)

78% effective for mumps (range: 49%−92%)

97% effective for rubella (range: 94%–100%)

Two doses - 2 doses of MMR are—

97% effective for measles (range: 67%–100%)

88% effective for mumps (range: 32%–95%)

 

Let me be clear - I am not against vaccinating for measles given that there is a risk of severe and permanent health complications from a measles infection.  Since measles vaccines were introduced in the early 1960s and the MMR vaccines were developed in 1971, the incidence of measles has been reduced by 99.9 percent with an estimated 20 million lives being saved so there is little doubt that the measles vaccine is effective.  That said, the study quoted in this posting shows clearly that infection with the wild measles virus confers longer-lasting immunity to measles than the vaccines which suggests that vaccinating adults who have had measles is probably unnecessary and fear-mongering about requiring measles vaccines for adults by public health officials is just that, fear-mongering, about a vaccination that is not necessarily based on science and will only serve to "fill the wallets" of Big Pharma.