Mumps is a mild viral infection similar to a cold. Symptoms can include headaches, fever and the typical swelling of parotid glands, which are located just forward and below the ear. It is spread through coughs and sneezes. Complications are rare.  25-30% of mumps cases are thought to be subclinical, meaning there are no symptoms. 
According to Dr Jayne Donegan, a doctor and medical researcher, the British National Formulary stated even just a few years before the MMR vaccine was introduced: “Since mumps and its complications are very rarely serious, there is little indication for the routine use of mumps vaccine”. 
Complications, rare as they are, can include swollen testicles (orchitis) or ovaries in patients who get mumps after they have gone through puberty. This doesn’t cause infertility in females but for males, the NHS says, out of those who do get orchitis, “1 in 10 men will experience a drop in their sperm count (the amount of healthy sperm that their body can produce). However, this is very rarely large enough to cause infertility.” 
Meningitis is often stated as a possible complication and although this is true, this viral meningitis, unlike bacterial meningitis, is much less severe and usually resolves without treatment within 7-10 days, resulting in complete recovery. 
In 1980 a Dutch study found that 90% of subjects got mumps before the age of 14. They also found that 25-30% of cases were subclinical (no symptoms).  Almost all adults (95%) retained immunity into adulthood.
Today there seems to be a shift into older age groups, where complications are more likely. [5,6,7] This could be a consequence of childhood immunisations shifting the burden of the illness into older patients, in whom the vaccine-induced immunity has waned. This has been seen in other diseases vaccinated against but is, in the case of mumps, difficult to reconcile with the fact that the vaccine does not seem to work in protecting children either.
In fact, mumps vaccination appears to be entirely ineffective.
In Scotland in a 2011 outbreak, 53% of patients were fully vaccinated and another 30% partially so. 
In a 2006 nationwide epidemic in the US, 63% of mumps cases happened despite two doses of MMR. 
A 2013 study in the US Territory of Guam found that among all the mumps cases in school-age patients, 93% had had 2 doses of MMR.
In Walsall, UK, in 2000, 68% of cases occurred in patients who had had 2 MMR shots and 18.5% in those who had had one dose. 
In 1991, an outbreak in Tennessee, USA, occurred in a school where 98% of students were vaccinated. Among 68 students who got ill with mumps, 67 had been vaccinated. The report concludes: “Most mumps cases were attributable to primary vaccine failure.”
Another study from the US in 1991 examined mumps cases between 1988 and 1989 during an outbreak in Kansas and found that among primary and secondary school students, 97.6% had been vaccinated.
A 1995 study entitled “Mumps outbreak in a highly vaccinated school population. Evidence for large-scale vaccination failure” found that during an outbreak among a high school population, 95% of the students were vaccinated and out of 54 students who got mumps, 53 were vaccinated.
In a 2007-2008 outbreak among Australian Aboriginals, 52% had had 2 doses of MMR 
Some of the older studies were done when only one dose of MMR was given, and the authors hoped that two doses would work better. But as can be seen from later studies, this was not the case.
Mumps vaccination is part of the MMR vaccine. It seems odd that there is so much controversy over this combined 3-in-1 vaccine when really its use is entirely pointless. It makes no sense to vaccinate against either Mumps or Rubella (especially in infancy) and the decision whether to give the MMR vaccine should therefore be straight forward. Unfortunately single vaccines aren’t generally available in the UK and where they are they have to be paid for privately. So it’s often a matter of all or nothing.
- NHS website accessed January 2014
- Childhood Vaccinatable Diseases And Their Vaccines – A review by Dr Jayne LM Donegan, 2010
- NHS website accessed June 2017
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- Center for Disease Control and Prevention website accessed June 2017
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