Mumps vaccine effectiveness and waning immunity

MMR-vaccine-mumpsIn a previous article, from our vaccine legal expert, Dorit Reiss, we learned that there’s a whistleblower lawsuit against Merck regarding the possibility that the company may have engaged in some inappropriate actions in determining the effectiveness of the MMR vaccine (for mumps, measles and rubella), specifically the mumps component of the vaccine. As Reiss stated, despite the suit (and recent ruling which just whether the case could go forward) being a boon to the antivaccination crowd, so far no facts have actually been presented.

In essence, the whistleblowers claim that Merck, the manufacturer of the MMR vaccine, through either direct falsification or poor study design, may have overstated the effectiveness of the mumps component of the vaccine. Merck had been claiming that the vaccine was approximately 95% effective (meaning at least 95% of children given the vaccine were protected against the disease).

So let’s be clear about this so-called whistleblower lawsuit–no evidence has been presented, and that evidence hasn’t been cross-examined. And one more thing–courts do not decide science, it’s not their role. Science is not a debate, it is a cold evaluation of evidence. And in science, the weight of the evidence is both in quality and quantity. Unless you’re a complete anti-science cult member, whatever this court decides, whatever malfeasance was practiced by Merck, whatever the whistleblowers have to say, the scientific evidence tells us that the mumps vaccine component is highly effective and extremely safe.

It’s time to just look at the science, because that’s why we’re here. Before we look at the real-world effectiveness of the mumps component of the MMR vaccine, I want to make a very clear point. The MMR vaccine absolutely does not cause autism, and is incredibly safe. Case closed, and only delusional cultists think otherwise, based on imaginary data and ludicrous anecdotes.

I still find it incredible that many people believe that mumps is a minor disease. Part of that is because the last major outbreak of mumps amongst children was in 1967, when over 186,000 children were infected, something we don’t see any more. Moreover, mumps can cause some dangerous and permanent complications. The disease itself is known for the swelling of cheeks and upper chin as a result of the swelling of the salivary glands. Although most individuals who catch the disease recover after 1-2 weeks, the disease can cause some serious complications:

  • The most common complication is inflammation of the testicles (orchitis) in males who have reached puberty; rarely does this lead to fertility problems. However, recent epidemiological research has shown that males who are unvaccinated against mumps have small but significant increased risk for infertility.
  • Inflammation of the brain and/or tissue covering the brain and spinal cord (encephalitis/meningitis)
  • Inflammation of the ovaries (oophoritis) and/or breasts (mastitis) in females who have reached puberty
  • Deafness

mumps_posterYes, these complications are rare. But if we quit vaccinating against mumps, and go back to a time where there were 186,000 American children infected by mumps every year (or approximately 270,000 using the current USA population), even if the complication rate is 5% or so, that’s 13-15,000 children a year. Why is it that the antivaccination world dismisses that number? My guess is that these arrogant and ignorant fools think that their children will not have a complication, because their children are genetically superior. Or eat organic, GMO-free food. Or because children of wealthy parents never get sick, because you know, money buys a better doctor to save their kids from mumps complications. Whatever the reason that makes the antivaccination crowd think that those who have complications are lesser human beings, they would be wrong, infectious diseases are mostly random events that hit everybody. Well, unless you want to lock your children in a house with filtered air and sterile food.

For those of you with more rational minds about diseases, mumps is not that minor, and again being rational, we want to prevent suffering of our children from vaccine preventable diseases.

Let’s get back to vaccine effectiveness. Here are some of the unbiased, peer-reviewed, published research on the overall effectiveness of mumps vaccines:

There are literally dozens of studies that establish the relatively high effectiveness of the vaccine. So whether Merck fudged data or not is almost immaterial, though doing any fudging is an indictment of their moral authority in producing data for vaccines, something I will find evidence if they are really found guilty of these violations.

But there might be another reason why effectiveness of the mumps component is lower than expected–waning immunity. Although the immune system remembers all antigens theoretically forever, in reality, without constant challenges, immunity could wane over time. With each breath, we inhale literally millions of antigens, so the database of antibodies within our immune system gets pretty crowded. It’s possible that the database can be unlimited, but we’re not sure.

There is strong evidence that the recent increase in mumps outbreaks in the USA may be related to both a lower antibody level over time and incomplete vaccination (meaning getting only 1 of 2 doses). In addition, because of nearly non-existent exposure to the wild virus (thanks to the success of vaccinations), those who only had one dose never get a “natural” booster. They then are at risk to the disease, especially in a closed environment like a college, when someone brings the virus from another country where mumps has larger epidemics or is endemic, like the UK where a recent outbreak hit over 70,000 people.

Other evidence indicates that even with those individuals with two doses during childhood have waning immunity–when they become adults, they might become more susceptible to mumps, especially as the time between immunization and exposure to the wild virus increases.

Scientific research has given us a better view of how the immunity against mumps begins to wane over time, irrespective of whatever data comes from the manufacturer of the vaccine, Merck. The research also tells us that even those with waning immunity (the term is not “lost immunity”), the course and severity of the mumps infection is less than those who were never vaccinated.

Again, let me make this clear. What Merck did or did not do is irrelevant, absolutely unrelated to the safety and effectiveness of the MMR vaccine, specifically for mumps. The scientific evidence clearly shows that effectiveness is extremely high, and Merck’s data for mumps is right on the upper end of the statistical errors for what has been found in independent research. And more than that, waning immunity may be contributing to a slight lower effectiveness, something outside of the research done by Merck.

Nevertheless, because of what we know about waning immunity, it’s possible that the schedule for vaccines may have to be reconfigured. Maybe, like tetanus vaccines, it has to be repeated every 10 years or so, boosting our immunity in a naturally effective manner. Scientific research will give us future choices in either better vaccinations or boosters, so that we keep mumps at bay.

And let’s remember vaccines save lives.

Use the Science-based Vaccine Search Engine.

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The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!