Tag: wild strains

Is Mutating Mumps More Than the MMR Can Manage?

It is not news that we have been seeing more cases of mumps in recent years.

It is also isn’t news that many of these folks are vaccinated.

“Long Beach has been hit with a mumps outbreak that is vaccine-resistant. According to health officials in the Long Island town, almost two dozen individuals are believed to have contracted the virus, with four confirmed cases and at least 14 suspected ones.”

Natural News

That sites like Natural News is putting out misinformation about vaccine-resistant strains of mumps also shouldn’t be news to anyone.

Why Do Folks Think That Vaccine-Resistant Viruses Are Causing Mumps Outbreaks?

So are vaccine-resistant mumps viruses causing outbreaks?

There is no good evidence of that and plenty of evidence that our current vaccines, even though they aren’t perfect, do cover all wild strains of mumps.

Unfortunately, it might not be surprising that some folks are confused about vaccine-resistant mumps viruses, when we have health officials saying things like:

“Sometimes nature throws a strain at us that might have mutated a little bit, and coverage of the vaccine is not 100 percent.”

Dr. Lawrence Eisenstein, Nassau County Health Commissioner

Dr. Eisenstein’s “might have mutated a little bit” comment got twisted into “the outbreak is most likely attributable to a new strain of the virus that is resistant to vaccines” by health reporters

And out of Arkansas, where there have also been large mumps outbreaks:

“We are actually to the point that we are worried that this vaccine may indeed not be protecting against the strain of mumps that is circulating as well as it could.”

Dr. Dirk Haselow, Arkansas State Epidemiologist

Of course, to say that the vaccine may not be protecting folks “as well as it could” doesn’t mean it doesn’t work because the wild type mumps virus has evolved or mutated enough to surmount our current MMR vaccine.

Is Mutating Mumps More Than the MMR Can Manage?

Although anything is possible, we fortunately have plenty of research that says that the mumps virus hasn’t mutated and that the MMR still works.

During an outbreak, universities make sure students are up-to-date with their MMR vaccines.
During an outbreak of mumps, some kids are getting a third dose of the MMR vaccine.

In fact, although the MMR vaccine is made from the A strain or genotype of mumps, it provides good protection against all 12 known strains of wild mumps viruses, including genotype G that has been causing most of the recent outbreaks.

But how can it cover a different strain of virus that isn’t in the vaccine?

Because not all viruses and vaccines are like influenza.

“The genotyping of the mumps virus is based on the Small Hydrophobic (SH) protein, a nonstructural protein and genetically the most variable one. Based on the SH-protein 12 different mumps viruses were detected up to now. In recent epidemics in Western countries the genotype G was mainly detected, while the mumps viruses used in the live attenuated mumps vaccines belong to genotype A (Jeryl Lynn) and to a lesser extent to genotype B (Urabe). However, antibodies against the SH protein have not yet been observed in human serum. It is, therefore, unlikely that antibodies against the SH protein play an important role in antibody-mediated virus neutralization.”

Sabbe et al. on The resurgence of mumps and pertussis

It is well known that you need a very specific match of the flu vaccine to the wild flu virus that is going around to get good protection, but for many other viruses, the differences that determine the strain or genotype have nothing to do with how antibodies will recognize the virus.

“Since mumps virus is monotypic, vaccine from any strain should provide lifelong protection against subsequent infection.”

Palacios et al. on Molecular Identification of Mumps Virus Genotypes from Clinical Samples: Standardized Method of Analysis

Like measles, mumps is a monotypic virus.

“Studies have demonstrated that blood sera from vaccinated persons cross-neutralizes currently circulating mumps strains.”

CDC on Mumps for Healthcare Providers

And like measles, the mumps vaccine (MMR), protects against all strains of wild mumps viruses.

“Compared with attack rates of 31.8%–42.9% among unvaccinated individuals, attack rates among recipients of 1 dose and 2 doses of the Jeryl Lynn vaccine strain were 4%–13.6% and 2.2%–3.6%, respectively.”

Dayan et al. on Mumps Outbreaks in Vaccinated Populations: Are Available Mumps Vaccines Effective Enough to Prevent Outbreaks?

And like other vaccines, the mumps vaccine (MMR) works.

Waning immunity may be an issue, but that certainly isn’t a reason to skip or delay this vaccine and put your kids, and everyone else, at risk to get mumps.

What to Know About Mumps Strains and Outbreaks

The MMR vaccines covers all strains of mumps and getting fully vaccinated is the best way to make sure your kids don’t get mumps.

More on Mumps Strains and Outbreaks

Measles Vaccines vs Measles Strains

Most people understand that for every virus or bacteria, their can be multiple strains of the same organism that cause disease.

For example, there is flu A and B, swine flu, bird flu, and even dog flu.

In the case of flu, those different strains are a problem, because having immunity to one, doesn’t mean that you will have immunity to others. In fact, usually you won’t, whether it is natural immunity from a previous infection or immunity from a vaccine.

Pains with Strains

Do we have the same issues with other diseases?

We certainly have situations in which vaccines don’t cover all disease strains, including:

  • Gardasil – now covers nine strains of HPV that cause 90% of cervical cancers
  • Hib – only covers Haemophilus influenzae type b, which causes invasive disease, like meningitis, pneumonia, and sepsis, but not other Haemophilus influenzae strains that can cause ear infections
  • Polio – originally protected against three serotypes of polio, but monovalent (one strain) and bivalent (two strains) oral poliovirus vaccines have also been available to respond to outbreaks and bOPV is the one used for routine immunization, except in industrialized, polio-free countries that use the IPV shot
  • Prevnar – now covers 13 strains of Streptococcus pneumonia
  • Rotavirus – protects against severe disease caused by rotavirus strains that aren’t even in the vaccine

Fortunately, even when a vaccine doesn’t cover all strains, it does cover those that most commonly cause disease.

Measles Genotypes

Knowing the genotype of a measles strain can help you understand where measles outbreaks are coming from.
Knowing the genotype of a measles strain can help you understand where measles outbreaks are coming from.

What about measles?

There are at least 24 different genotypes of measles that come from 8 different clades (A-H), with even more wild type virus strains (based on those genotype).

These genotypes include A (all vaccine strains are genotype A), B2, B3, C1, C2, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, G2, G3, H1, and H2.

In general, genotypes are restricted to a specific part of the world, such as:

  • African Region – B2, B3
  • Eastern Mediterranean Region – B3, D4, D8
  • European Region – D4, D5, D6
  • Southeast Asian Region – D4, D5, D8, D9, G2, G3, H1
  • Western Pacific Region – D5, D9, G3, H1

In countries that have eliminated measles, like the United States, the genotypes that are found will depend on from where the measles strain was imported.

Additionally, five genotypes, B1, D1, E, F, and G1 are now inactive.

Measles Strains

Specific strains of measles viruses include the vaccine strains (Edmonston, Moraten, Zagreb, Schwarz, AIK‐C, CAM, Leningrad-16, and Shanghai-191, etc.) plus wild strains, like:

  • MVi/NewYork.USA/94 – a wild strain of B3 genotype
  • Johannesburg.SOA/88/1 – a wild strain of D2 genotype
  • Manchester.UNK/30.94  – a wild strain of D8 genotype
  • Hunan.CHN/93/7 – a wild strain of H1 genotype

Why so many vaccine strains?

It may come as a surprise to some people, but the whole world doesn’t use the same vaccines. For example, unlike the United States, Japan has used measles vaccines derived from AIK‐C, CAM, and Schwarz strains of the measles virus.

And just how many wild strains of measles are there? It’s hard to know, but consider that a study of 526 suspected measles cases from 15 outbreaks over 3 years in one state of India found at least 38 different strains.

Myths About Measles Strains

Do the measles vaccines cover all of the measles strains that cause outbreaks around the world?

Yes they do, despite the myths you may hear about mutated measles strains.

This came up a lot during the Disneyland measles outbreak, when folks first tried to place blame on a vaccine strain and then on the fact that the outbreak strain didn’t match the vaccine strain.

“…California patients were genotyped; all were measles genotype B3, which has caused a large outbreak recently in the Philippines…”

CDC Measles Outbreak — California, Dec 2014–Feb 2015

And it is coming again in the latest measles outbreak in Minnesota. Could that outbreak be caused by a vaccine strain? Anything is possible, but it’s not. A communication’s director for the Minnesota Department of Health has confirmed that “that the virus strain making people sick in this outbreak is the B3 wild-type virus.”

Of course, none of these outbreaks are started by a vaccine strain of measles shed from someone who was recently vaccinated. It also had nothing to do with the fact that the strains didn’t match – after all we aren’t talking about the flu.

These outbreaks are imported from other countries by folks who typically aren’t vaccinated or are incompletely vaccinated and mostly spread among other people who are unvaccinated.

So what’s the most important thing to understand when considering all of these vaccine strains and wild strains of measles? It is that “there is only 1 serotype for measles, and serum samples from vaccinees neutralize viruses from a wide range of genotypes…”

In other words, the measles vaccine works against all strains of measles in all genotypes of measles. That makes sense too, because the measles virus, unlike influenza, is monotypic.

There is only one main type of measles virus, despite the many small changes in the virus that can help us identify different strains and genotypes. And these changes don’t affect how antibodies protect us against the measles virus.

What To Know About Measles Strains

The best way to get protected against all measles strains is to get vaccinated with two doses of the MMR vaccine.

More About Measles Strains

Updated May 23, 2017