Home » Vaccine Misinformation » Can MMR Shedding Start a Measles Outbreak?

Can MMR Shedding Start a Measles Outbreak?

Have you ever noticed that any time that there is a new outbreak of measles, folks tend to ask the same basic questions.

How did the outbreak start?

Why weren’t they vaccinated?

Was it from shedding?

Wait, what?

Shedding??? Really?

Can MMR Shedding Start a Measles Outbreak?

It seems that the idea that the MMR vaccine sheds and can lead to measles outbreaks is one of those anti-vaccine myths that just won’t go away.

It comes back with each new measles outbreak.

The myth that MMR shedding leads to measles outbreaks is commonly spread on Facebook, like this discussion on a recent outbreak at a Kansas City daycare center.
The myth that MMR shedding leads to measles outbreaks is commonly spread on Facebook, like this discussion on a recent outbreak at a Kansas City daycare center.

While the oral polio vaccine is indeed associated with shedding and vaccine associated disease, that doesn’t happen with MMR. Experts don’t even recommend any restrictions for use of the MMR vaccine for household contacts of people who are immunosuppressed. And yes, your kids can even visit a cancer patient if they just had their MMR, as long as they don’t have RSV, the flu, or some other contagious disease.

What about the fact that a study once found measles virus RNA in the urine of of kids who had recently been vaccinated? Doesn’t that mean that they were shedding the vaccine virus?

No. It doesn’t.

To be considered shedding, those measles virus RNA particles in their urine would have to be contagious. Now, measles is spread by respiratory secretions. So how are measles virus RNA particles in urine going to become airborne and get someone else sick?

They don’t.

Another Facebook post about MMR and shedding.
Most measles outbreaks in daycare centers have been started by an unvaccinated child or worker who traveled out of the country.

But what about that case in Canada? Anti-vaccine folks like to bring this up when they talk about shedding. In 2013, there was a case of vaccine-associated measles. That proves that the vaccine sheds, right?

Absolutely not!

“Of note, only one case report of transmission from vaccine-associated measles has been identified.”

Murti et al. on Case of vaccine-associated measles five weeks post-immunisation, British Columbia, Canada, October 2013

That child got measles about 5 weeks after she was vaccinated in the middle of a measles outbreak. Because she had no links to the other cases and she tested positive for vaccine-strain measles, it is thought that she had MMR vaccine-associated measles, which is extremely rare.

Shedding Light on Measles Outbreaks in Daycare

MMR shedding is not causing outbreaks of measles – or rubella and mumps, for that matter.

If shedding from the MMR, by any method, got kids sick, then why aren’t there even more cases of measles?

Daycare centers everywhere have a mix of infants and toddlers, including some who are intentionally unvaccinated, those who are too young to get their first MMR, and those who are just getting vaccinated.

When a case of measles does pop up though, it isn’t because of shedding, it is typically because someone who wasn’t vaccinated traveled out of the country, got measles, and brought it back home, exposing others.

What to Know About MMR and Shedding

Measles outbreaks are not caused by shedding from the MMR vaccine.

More on the MMR and Shedding

Last Updated on

11 thoughts on “Can MMR Shedding Start a Measles Outbreak?”

  1. Children under the age of 12 can NOT visit someone receiving chemotherapy. Vaccines are generally given to children under the age of 12. I am not anti-vax and my children have been fully vaccinated. However my mother went through chemotherapy and the information in this article is incorrect.

  2. In published research of a recent measles outbreak, 38% of those tested for which strain they had, were infected with the vaccine strain. So if they don’t shed, how did do many in the outbreak become infected with the specific vaccine strain of measles. Please do your research before posting such dangerous information.

    1. If you’re referring to California 2014-2015, you’re dead wrong. If you’re referring to another case-study, let’s see your data but I’ll bet you dollars-to-donuts you’re still wrong.

  3. “When a case of measles does pop up though, it isn’t because of shedding, it is typically because someone who wasn’t vaccinated traveled out of the country, got measles, and brought it back home, exposing others.”

    Untrue. What is true is, when a case of measles does pop up though, it has been proven, time and time again, it is traced back to the vaccine-strain of the viruses, then outbreaks occur because of shedding. Nice lie though.

    If vaccines work, then why would people get infected by someone who traveled out of the country?

    1. RealScienceRules

      First, regarding your statement “when a case of measles does pop up though, it has been proven, time and time again, it is traced back to the vaccine-strain of the viruses, then outbreaks occur because of shedding.” FALSE. To prove your point, why don’t you please provide your scientific proof with a link to a peer reviewed study of your claim? Second, regarding your statement, “If vaccines work, then why would people get infected by someone who traveled out of the country?” Your question at the end of your post shows that you don’t understand this article at all, and how disease spreads. It’s very simple. UNVACCINATED people who travel from the United States often pick up diseases in foreign countries and bring them back into the United States and infect OTHER UNVACCINATED PEOPLE IN THE UNITED STATES. UNVACCINATED FOLKS CAUSE PROBLEMS. UNVACCINATED. It happens all the time. Now, if a VACCINATED person travels from the United States to a foreign country, there is zero, or very remote chance that they’ll bring back a disease. Please get educated from the right sources of information – respected scientists and doctors. Not anti-vax celebrities and parents. And VACCINATE, unless you have a valid medical reason not to.

  4. Phillip Lance Sheldon

    The Small Pox vaccine was successful because it used a less lethal, though similar virus. The Small Pox vaccine did not propagate the Small Pox virus. It’s a fool’s errand to hope that a disease can be eradicated by broadly propagating an attenuated version of the very disease. This strategy just perpetuates the disease’s foothold.
    The only hope of using attenuated virus type vaccines of a achieving Small Pox like success would be to reduce vaccination rates to high risk areas and individuals.

  5. Hmm, Interesting – would be more credible if you included in-text citations/footnotes to back claims instead of a pile of links at the end for the reader to sift through to find the source of each individual claim.

    1. I.e – outbreaks are never caused by shedding but usually the return of unvaccinated travelers. Your linked article doesn’t exactly include any data supporting that. It does link to another link with an rough list of 124 instances of measles possibly related to recent travelers.
      Of the 124, 21 have descriptions that include an association on unvaccinated individuals contracting measles and of that 21, 8 claim that the unvaccinated individual may have exposed others.
      So what about the other 103? We’re those all associated with vaccinated individuals ? If so that does not support your claim that typically measles outbreaks are “typically because someone who wasn’t vaccinated traveled out of the country, got measles, and brought it back home”
      Maybe what your saying is true but without proper citation it comes off like the data that led to your conclusions is intentionally being made difficult for the reader to find which leads me to believe it’s possibly because it won’t actually support your claims or doesn’t even exist and in which case I cannot refer to your article with any amount of credibility.

    2. I only point this out because it’s shorty research, unsupported bold claims etc. that lead to vaccine skepticism (which probably is not a bad thing to not blindly trust that the pharmaceutical industry is always putting health over profits – especially with the government influence it holds.

      Also I am not against vaccines in theory though I am skeptical of certain vaccines and the schedule of them.

      I also believe in the Nuremberg Code which many people seem to have forgotten — which established Informed Consent as a UNIVERSAL HUMAN RIGHT. The disregard for the the NC and increasingly coercive tactics limiting one’s own physical autonomy is becoming quite frightening.

      The amount of vaccines is also concerning. It is difficult to believe that anyone could not be skeptical of the endless expansion of the vaccine schedule.
      Perhaps I’m wrong but it would seem at some point, too many vaccines in short intervals would yield some pretty bad outcomes and more and more studies seem to be indicating that.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: