Can Mumps Vaccine Cause Injury & Death?

The Centers for Disease Control (CDC) report minor side effects from the MMR-V and MMR vaccines to include fever, injection site redness or rash, pain at the injection site, facial or neck swelling, pneumonia, full body rash, swelling of the brain and/or spinal cord covering, temporary low platelet count, temporary stiffness and pain at the joints, and seizures. Allergic reactions, serious injury, and death can also occur after vaccination.    A vaccine strain infection following vaccination may be the cause of the full body rash.       

There is a significantly greater risk of seizures following MMR-V vaccine in comparison to separate administrations of MMR and varicella vaccines if the MMR-V is given as the first dose of the series. 

Persons with serious immune disorders are at risk of developing a life-threatening infection if administered the MMR-V or MMR vaccine. Vaccination is not recommended in this population.   

Serious complications reported by Merck in the MMRII package insert during vaccine post-marketing surveillance include: 

• brain inflammation (encephalitis) and encephalopathy (chronic brain dysfunction);
• panniculitis (inflammation of the fat layer under the skin);
• atypical measles;
• syncope (sudden loss of consciousness, fainting);
• vasculitis (inflammation of the blood vessels);
• pancreatitis (inflammation of the pancreas);
• diabetes mellitus;
• thrombocytopenia purpura (blood disorder);
• Henoch-Schönlein purpura (inflammation and bleeding in the small blood vessels);
• acute hemorrhagic edema of infancy (rare vasculitis of the skin’s small vessels occurring in infants);
• leukocytosis (high white blood cell count);
• anaphylaxis (shock);
• bronchial spasms;
• pneumonia;
• pneumonitis (inflammation of the lung tissues);
• arthritis and arthralgia (joint pain);
• myalgia (muscle pain);
• polyneuritis (inflammation of several nerves simultaneously);
• measles inclusion body encephalitis (disease affecting the brain of immunocompromised persons);
• subacute sclerosing panencephalitis (fatal progressive brain disorder caused by exposure to the measles virus);
• Guillain-Barre Syndrome (GBS)(disease where the body’s immune system attacks the nerves);
• acute disseminated encephalomyelitis (ADEM) (brief widespread inflammation of the nerve’s protective covering);
• transverse myelitis (inflammation of the spinal cord);
• aseptic meningitis;
• erythema multiforme (skin disorder from an allergic reaction or infection);
• urticarial rash (hives, itching from an allergic reaction);
• measles-like rash;
• Stevens-Johnson syndrome (severe reaction causing the skin and mucous membranes to blister, die, and shed);
• nerve deafness (hearing loss from damage to the inner ear);
• otitis media (ear infection);
• retinitis (inflammation of the retina of the eye);
• optic neuritis (inflammation of the optic nerve);
• conjunctivitis (pink eye);
• ocular palsies (dysfunction of the ocular nerve);
• epididymitis (inflammation of the epididymis);
• paresthesia (burning or prickling of the skin);
• death.

Serious complications reported by Merck in the ProQuad package insert during vaccine post-marketing surveillance include: 

• measles;
• atypical measles;
• vaccine strain varicella;
• varicella-like rash;
• herpes zoster;
• herpes simplex;
• pneumonia and respiratory infection;
• pneumonitis;
• bronchitis;
• epididymitis;
• cellulitis;
• skin infection;
• subacute sclerosing panencephalitis;
• aseptic meningitis;
• thrombocytopenia;
• aplastic anemia (anemia due to the bone marrow’s inability to produce platelets, red and white blood cells);
• lymphadenitis (inflammation of the lymph nodes);
• anaphylaxis including related symptoms of peripheral, angioneurotic and facial edema;
• agitation;
• ocular palsies;
• necrotizing retinitis (inflammation of the eye);
• nerve deafness;
• optic and retrobulbar neuritis (inflammation of the optic nerve);
• Bell’s palsy (sudden but temporary weakness of one half of the face);
• cerebrovascular accident (stroke);
• acute disseminated encephalomyelitis;
• measles inclusion body encephalitis;
• transverse myelitis;
• encephalopathy;
• Guillain-Barré syndrome;
• syncope (fainting);
• tremor;
• dizziness;
• paraesthesia;
• febrile seizure;
• afebrile seizures or convulsions;
• polyneuropathy (dysfunction of numerous peripheral nerves of the body);
• Stevens-Johnson syndrome;
• Henoch-Schönlein purpura;
• acute hemorrhagic edema of infancy;
• erythema multiforme;
• panniculitis;
• arthritis;
•  

Serious complications reported by GlaxoSmithKline in the PRIORIX package insert during vaccine post-marketing surveillance have included: 

• Vasculitis (including Henoch-Schönlein purpura and Kawasaki syndrome);
• Thrombocytopenia and thrombocytopenic purpura;
• Anaphylactic reactions;
• Meningitis;
• “Mumps like” illness;
• “Measles like” illness;
• Orchitis;
• Epididymitis;
• Parotitis;
• Erythema multiforme;
• Arthralgia;
• Arthritis;
• Encephalitis;
• Cerebellitis;
• Cerebellitis-like symptoms (including transient gait disturbance and transient ataxia);
• Guillain-Barré syndrome;
• Transverse myelitis;
• Peripheral neuritis;
• Afebrile seizures;

A 2014 published study on the MMR-V vaccine in Canada determined that the risk of febrile seizures to be double in children receiving the MMR-V vaccine when compared to those receiving the MMR and varicella vaccine separately.  A 2015 meta-analysis concluded a two-fold increase in febrile seizures between 5 and 12 days or 7 and 10 days following MMR-V vaccination in children between the ages of 10 and 24 months. 

ProQuad vaccine contains albumin, a human blood derivative and as a result, a theoretical risk of contamination with Creutzfeldt-Jakob disease (CJD) exists. Merck states that no cases of transmission of CJD or other viral diseases have been identified and all virus pools, cells, bovine serum, and human albumin used in vaccine manufacturing are all tested to assure the final product is free of potentially harmful agents.

The MMRII and the ProQuad product inserts report that cases of measles inclusion body encephalitis, pneumonitis and death have occurred in severely immunocompromised individuals who were inadvertently vaccinated and disseminated mumps and rubella infections have also been reported in this population.

In the comprehensive report evaluating scientific evidence, Adverse Effects of Vaccines: Evidence and Causality , published in 2012 by the Institute of Medicine (IOM), 30 reported vaccine adverse events following the Measles, Mumps, and Rubella (MMR) vaccine were evaluated by a physician committee . These adverse events included measles inclusion body encephalitis, febrile seizures, arthritis, meningitis, Guillain Barre Syndrome, autism, diabetes mellitus, optic neuritis, transverse myelitis and more.

In 23 of the 30 measles, mumps, and rubella (MMR) vaccine-related adverse events evaluated, the IOM committee concluded that there was inadequate evidence to support or reject a causal relationship between the MMR vaccine and the reported adverse event, primarily because there was either an absence of methodologically sound published studies or too few quality studies to make a determination.  The IOM committee, however, concluded that the scientific evidence “convincingly supports” a causal relationship between febrile seizures, anaphylaxis, and measles inclusion body encephalitis in immunocompromised individuals and the MMR vaccine and favored acceptance of a causal relationship between transient arthralgia in both children and women and the MMR vaccine.  The IOM committee also concluded that it favored rejection of a causal association between both autism and the MMR vaccine and Type 1 diabetes and the MMR vaccine, however, both of these conclusions resulted following the review of only five epidemiological studies. 

A systematic review published in 2012  by the Cochrane Collaboration examined 57 studies and clinical trials involving approximately 14.7 million children who had received the MMR vaccine. While the study authors said they were not able to detect a “significant” association between MMR vaccine and autism, asthma, leukemia, hay fever, type I diabetes, gait disturbance, Crohn’s disease, demyelinating diseases or bacterial or viral infections, they added that:

“The design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate.” 

In an updated review published in April of 2020, the Cochrane Collaboration reviewed 87 safety studies associated with MMR, MMR-V, and MMR + Varicella vaccine. This review concluded that there was an association between MMR vaccines containing Leningrad-Zagreb and Urabe mumps strains and aseptic meningitis, but no evidence to support this association for MMR vaccines which contain the Jeryl Lynn mumps strains. This conclusion was based on the evaluation of nine studies, all of which were considered low certainty studies. The Cochrane Collaboration reports low certainty studies to be those where their confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. 

An association was also found between MMR vaccines and idiopathic thrombocytopenic purpura (ITP) and MMR, MMR-V, and MMR + Varicella vaccines and febrile seizures and the studies evaluated to make this determination were a combination of both moderate certainty and low certainty studies. Moderate certainty studies are those in which the Cochrane Collaboration are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. 

The Cochrane Collaboration reported that no association was found between MMR vaccine and encephalitis, encephalopathy, cognitive delay, type 1 diabetes, asthma, dermatitis/eczema, hay fever, leukemia, multiple sclerosis, gait disturbance, and bacterial or viral infections; however, all the studies that were evaluated were found to be either low certainty or very low certainty studies. Very low certainty studies are those in which the Collaboration have very little confidence in the effect estimate and that the true effect is likely to be substantially different from the estimate of effect. 

No association was found between autism spectrum disorders and MMR vaccines, and the studies evaluated were a combination of moderate certainty and low certainty studies. The Cochrane Collaboration also reported that there was insufficient evidence to support or reject an association between MMR vaccines and inflammatory bowel disease. 

Published studies have shown that the MMR vaccine components or excipients, particularly egg antigens and porcine or bovine gelatin, can trigger both immediate and delayed anaphylactic reactions.   

In November 2014, the National Vaccine Information Center published a special report The Emerging Risks of Live Virus and Virus Vectored Vaccines: Vaccine Strain Virus Infection, Shedding and Transmission.²⁸ This report reviewed the medical literature for evidence that live virus vaccine strain infection, shedding and potential for transmission occurs, including mumps vaccine strain infection and shedding.

In 2006, a published report confirmed the transmission of Leningrad-3 live attenuated mumps vaccine virus infection from healthy vaccinated children in Russia to close contacts of previously vaccinated children.  The six vaccinated children had mumps symptoms, but the 13 close contacts did not have symptoms even though some of them tested positive for mumps vaccine strain infection.

In 2008, a published report confirmed the transmission of L-Zagreb mumps vaccine strain virus infection and transmission by three vaccinated children in Croatia to five adult parent contacts. Mumps symptoms began in the children within three weeks of vaccination and symptoms began in the parents within five to seven weeks after the children were vaccinated. One of the affected adults suffered mumps vaccine strain associated aseptic meningitis. 

Merck’s ProQuad vaccine product insert reports that transmission of varicella vaccine virus may occur between vaccine recipients and susceptible contacts, including high risk individuals resulting in both the development or non-development of varicella-like rash. As a result, Merck cautions that vaccine recipients should attempt to avoid close contact with high-risk individuals. This high-risk population includes pregnant women who lack a positive history of illness or vaccination and their newborn infants, any infants born prior to 28 weeks gestation, and all immunocompromised individuals. 

Both wild-type mumps and the live Urabe mumps vaccine strain are causally associated with aseptic meningitis (inflammation of the brain), a mumps virus infection complication.      The MMRII and ProQuad vaccines contain the Jeryl Lynn mumps vaccine strain and both product inserts deny that this particular strain can cause aseptic meningitis.    PRIORIX contains the RIT 4385 strain of live attenuated mumps virus, which is derived from the Jeryl Lynn strain. Though PRIORIX is derived from the Jeryl Lynn strain, health officials state there is no causal link to aseptic meningitis. 

As of March 29, 2024, there have been 478 deaths reported to VAERS in association with the MMR vaccine and 40 deaths associated with the MMR-V vaccine. However, the numbers of vaccine-related injuries and deaths reported to VAERS may not reflect the true number of serious health problems that occur develop after MMR vaccination.

Even though the National Childhood Vaccine Injury Act of 1986 legally required pediatricians and other vaccine providers to report serious health problems following vaccination to federal health agencies (VAERS), many doctors and other medical workers giving vaccines to children and adults fail to report vaccine-related health problem to VAERS. There is evidence that only between one and 10 percent of serious health problems that occur after use of prescription drugs or vaccines in the U.S. are ever reported to federal health officials, who are responsible for regulating the safety of drugs and vaccines and issue national vaccine policy recommendations.       

As of April 1, 2024, there have been 1,198 claims filed so far in the federal Vaccine Injury Compensation Program (VICP) for 66 deaths and 1,132 injuries that occurred after vaccination with a mumps containing vaccine (MMR, MMR-V, mumps). Of that number, the U.S. Court of Claims administering the VICP has compensated 464 children and adults, who have filed mumps vaccine injury. 

One example of an MMR vaccine injury claim awarded compensation in the VICP is the case of O.R. On February 13, 2013, O.R. received the MMR, Haemophilus Influenzae type B, Pneumonia (Prevnar 13), Hepatitis A, and Varicella vaccines. That evening, following vaccination, she became feverish and irritable prompting her mother to contact the doctor. The doctor advised O.R.’s mom to administer Benadryl and Tylenol for her symptoms. The fever persisted for several days and was followed by a severe seizure resulting in cardiac and respiratory arrest. The cardiac arrest and seizures caused O.R. to develop encephalopathy, kidney failure, severe brain injury, low muscle tone and cortical vision impairment. After several months of inpatient hospitalization, O.R. was discharged home with 24-hour supervised medical care.  On November 20, 2017, the court conceded that the MMR vaccine caused her encephalopathy and O.R. was awarded a $101 million dollar settlement to cover medical expenses for the rest of her life.   

For more information on reported MMR vaccine risks, adverse events and contraindications, see Measles and Measles Vaccine here.

IMPORTANT NOTE: NVIC encourages you to become fully informed about Mumps and the Mumps vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

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