Vaccine Info

M-M-R II Vaccine

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Last reviewed
April 5, 2021

M-M-R II Vaccine Description

Merck's M-M-R II vaccine is known as the Measles, Mumps, and Rubella Virus Vaccine Live, containing weakened forms of measles virus, mumps virus, and rubella virus. The M-M-R II vaccine works by helping the immune system protect itself from these viruses, says the company.

The vaccine's active ingredients include weakened forms of measles, mumps, and rubella (MMR) viruses. The inactive ingredients include sorbitol, sucrose, hydrolyzed gelatin, recombinant human albumin, fetal bovine serum, other buffer and media ingredients, neomycin.

Clinical studies of 284 triple-seronegative children between 11 months to 7 years of age demonstrated that M-M-R II is highly immunogenic and generally well-tolerated. In these studies, a single injection of the vaccine-induced measles hemagglutination-inhibition (HI) antibodies in 95% of the participants, mumps neutralizing antibodies in 96%, and rubella HI antibodies 99% of susceptible persons.

However, a small percentage (1%-5%) of vaccinees may fail to seroconvert after the primary dose. The most common side effect of vaccination with M-M-R II is pain at the shot site for a short time. Other side effects may include fever or rash.

The MMR vaccine was developed by Maurice Hilleman and was licensed for use by Merck in 1971.

M-M-R II Vaccine Indication

The vaccine is indicated for simultaneous vaccination against measles (rubeola), mumps, and rubella (German measles). This vaccine is usually given to people 1-year of age or older.

M-M-R II is contraindicated in specific individuals, including those with: a history of hypersensitivity to any component of the vaccine, including gelatin; a history of anaphylactic or anaphylactoid reaction to neomycin; blood dyscrasias, leukemia, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic systems; primary or acquired immunodeficiency conditions; family history of congenital or hereditary immunodeficiency or receiving immunosuppressive therapy; an active febrile illness; or those who are pregnant.

If vaccination of postpubertal females is undertaken, pregnancy should be avoided for 3-months following vaccination.

M-M-R II Vaccine Dosage

The U.S. CDC's ACIP committee recommends administering the 1st dose of M-M-R II at 12 to 15 months of age and administering the second dose of M-M-R®II at 4 to 6 years ago.

The M-M-R II vaccine is given as a shot administered subcutaneously, preferably into the arm's outer aspect. The dose of the vaccine is the same for everyone. If your child gets the shot when he or she is one year old or older, a second dose is recommended.

Often, the 2nd dose is given right before the child goes to elementary school (4 to 6 years of age). If your child is less than one year old when he or she first gets the shot, a second dose should be given when 12 to 15 months old. If a 3rd vaccination is prescribed, a dose should be given between 4 and 6 years of age.

M-M-R II Vaccine News

March 13, 2021 - Since the previous monthly measles update by the ECDC's Communicable Disease Threats Report, issued on February 12, 2021, two countries have reported five new measles cases in the EU/EEA: Germany (4) and Spain (1). In 2021, no new deaths have been reported by EU/EEA countries, says the ECDC.

March 11, 2021 - A SARS-CoV-2 vaccine candidate developed by researchers from The Ohio State University (OSU) is leveraging a measles virus to potentially protect people from COVID-19. Using a measles virus (rMeV) vaccine strain as the backbone, they developed a series of recombinant attenuated vaccine candidates expressing various forms of the SARS-CoV-2 spike (S) protein and its receptor-binding domain and evaluated their efficacy animals. The OSU researchers found that rMeV expressing stabilized prefusion S protein (rMeV-preS) was more potent in inducing SARS-CoV-2–specific neutralizing antibodies than rMeV expressing full-length S protein (rMeV-S).

March 1, 2021 - Recent increases in incident measles cases in the United States and across the globe underscore the need to more fully understand the societal cost of measles cases and outbreaks and the economic consequences of under vaccination. The overall societal cost of the 2019 Clark County measles outbreak was ∼$3.4 million ($47,479 per case or $814 per contact). The majority of the costs (∼$2.3 million) were incurred by the public health response to the outbreak, followed by productivity losses (∼$1.0 million) and direct medical costs (∼$76 000).

March 1, 2021 - The U.S. CDC reported health officials in certain African countries had reported measles outbreaks, meaning the number of measles cases is higher than normal. All travelers to Africa, including infants and pre-school-aged children, should be fully protected against measles.

March 1, 2021 - The Lancet published a commentary: Measles: the long walk to elimination drawn out by COVID-19. Dr. Wariri and colleagues offer valuable insight into the situation of measles control in west Africa over the past two decades. A global mobilization is necessary to fight against the scourge of measles in the post-COVID-19 era. Alongside proven strategies, innovative actions and research must be carried out to ensure that vaccination reaches all children and ensure that no one is left behind.

February 8, 2021 - GAVI researched the long-term effects of measles on the human immune system. Researchers collected blood samples from 77 unvaccinated children before and after getting infected with the virus during an outbreak in the Netherlands. They tracked the antibodies' changes (the particles that fight off pathogens) in the children’s bloodstream. They found that measles wipes out up to 73% of these antibodies, leaving these children unprotected against other diseases for months and sometimes years. This study's findings further show the importance of vaccination.

February 4, 2021 - Merck Announces Fourth-Quarter and Full-Year 2020 Financial Results.

January 25, 2021 - Merck announced that the company is discontinuing the development of its SARS-CoV-2/COVID-19 vaccine candidates, V590 and V591. This decision follows Merck’s review of findings from Phase 1 clinical studies for the vaccines. In these studies, both V590 and V591 were generally found well-tolerated, but the immune responses were inferior to those seen following natural infection and those reported for other SARS-CoV-2/COVID-19 vaccines. 

January 7, 2021 - Pandemic-Related MMR Vaccine Decline Persists. The researchers found that from March 2017 to March 2020, the average proportion of 16-month-old children with MMR vaccination was 72 percent, which decreased to 66.8 percent from April to May 2020 and then to 62.4 percent from June to August 2020.

December 25, 2020 - Washington DC legislation: B23-0171 - Minor Consent for Vaccinations Amendment Act of 2019. BILL SUMMARY - As introduced, this bill permits a minor of any age to consent to receive a vaccine where the vaccination is recommended by the US Advisory Committee on Immunization Practices. It also establishes that if a minor can comprehend the need for, the nature of, and any significant risks inherent in medical care, informed consent is confirmed.

December 17, 2020 - In this study, researchers focused on the first MMR vaccination because they hypothesized that any changes in vaccination rates due to COVID-19 pandemic-related closures likely would be identified earliest among young children who require frequent preventive visits. From March 2017 to March 2020, the average proportion of 16-month-old children with MMR vaccination was 72.0%, which decreased to 62.4% (P = .02) by August 2020. It is too soon to evaluate whether there has been a decrease in the second MMR vaccination. Despite efforts to have families return for preventive care, the AAP says there is a need for novel strategies to ensure the delivery of comprehensive preventive services, including catch-up vaccination efforts that might need to extend beyond the end of the pandemic to protect our community from vaccine-preventable outbreaks.

December 16, 2020 - A new study published in Nature by a team led by researchers from the Institute for Health Metrics and Evaluation at the University of Washington found MCV1 coverage estimates show overall progress from 2000 to 2019. Moreover, 62 out of 101 countries in the study increased national-level MCV1 coverage while reducing subnational geographical inequalities over time, which is a noteworthy achievement.

December 1, 2020 - The Journal Pediatrics published a study found in Ohio, from March 2017 to March 2020, the average proportion of 16-month-old children with MMR vaccination was 72.0%, which decreased to 62.4% in August 2020.

November 30, 2020 - Study: the bivalent MeV/SARS-CoV-2 vaccine candidate has several desirable properties concerning its immunogenicity and efficacy against SARS-CoV-2. Furthermore, the concurrent induction of anti-MeV immunity would allow its use in the context of routine measles immunization schedules. Such a MeV-based COVID-19 vaccine could be included in the currently applied MMR (measles, mumps, rubella) vaccine, providing additional protection against SARS-CoV-2.

November 20, 2020 - Study: Analysis of Measles-Mumps-Rubella Titers of Recovered COVID-19 Patients. These results demonstrate a significant inverse correlation between mumps titers from MMR II and COVID-19 severity. This study's significance is that it showed that mumps titers related to the MMR II vaccine are significantly and inversely correlated with the severity of COVID-19-related symptoms, supporting the theorized association between the MMR vaccine and COVID-19 severity.

October 23, 2020 - Vaccination Coverage by Age 24 Months Among Children Born in 2016 and 2017 — National Immunization Survey-Child, United States, 2017–2019.

October 23, 2020 - A study published in the American Journal of Medicine suggested 'the MMR vaccine may protect against COVID-19, including high-risk individuals, such as the elderly with comorbidities, and health care workers and first responders with COVID-19 patients, especially individuals living in long-term care facilities and the related institutional staff.' These findings suggest the MMR vaccine may protect against COVID-19, including high-risk individuals, such as the elderly with comorbidities, and health care workers and first responders with COVID-19 patients, especially individuals living in long-term care facilities and the related institutional staff. Clinicians caring for such high-risk patients should consider the benefit/cost ratios of MMR vaccination to justify using this simple, low-risk intervention to reduce COVID-19 disease, primarily until a specific vaccine is approved.

October 14, 2020 - A research team led by Dr. Larenas-Linnemann, working at Medica Sur, Mexico City, reported their clinical observations in 255 subjects vaccinated measles-mumps-rubella (MMR) vaccine since the start of the COVID-19) pandemic. The concept of trained immunity based on a heterologous immune response with nonspecific memory dates back about a decade ago. It refers to the enhanced immune response to a certain pathogen after being exposed (by vaccination or natural illness) to another nonrelated pathogen1. Matricardi analyzed this in the context of the COVID‐pandemic. Conclusive evidence of the MMR vaccine's value to reduce COVID-19 complications requires a prospective, randomized trial.

October 11, 2020 - The two measles vaccination campaigns in the Central African Republic appear to have been largely successful in slowing the measles outbreak that was declared at the start of 2020. However, children aged 6 months to 10 years will have received only one measles vaccination dose. The lack of a second dose has led to declining immunity elsewhere in the region, which needs to be considered when planning future activities.

October 7, 2020 - The Philipines Department of Health and Local Government Units will conduct nationwide measles, rubella, and polio supplemental immunization activity starting October 26, 2020. In the Philippines, an estimated 2.4M children under five are susceptible to the measles virus.

September 23, 2020 - BMJ commentary: Containing measles in conflict-driven humanitarian settings

September 15, 2020 - According to CDC immunization schedules, all travelers to Africa, including infants and pre-school-aged children, should be fully vaccinated against measles.

September 3, 2020 - Global trial to test whether the MMR vaccine protects front-line health-care workers against COVID-19.

September 3, 2020 - An international research network announced it is launching the CROWN CORONATION phase 3 clinical trial to evaluate whether the vaccine for measles, mumps, and rubella (MMR) can protect front-line health-care workers against infection from SARS-CoV-2, the virus that causes COVID-19.

September 1, 2020 - A study was published in The Lancet: Immunogenicity and persistence of trivalent measles, mumps, and rubella vaccines: a systematic review and meta-analysis. Our meta-analysis provides estimates of primary and secondary vaccine failure, which are essential to improve the accuracy of mathematical and statistical modeling to understand and predict the occurrence of future measles, mumps, and rubella outbreaks in countries with high vaccine uptake.

July 30, 2020 - The Lancet published: Persistence of US measles risk due to vaccine hesitancy and outbreaks abroad.

June 19, 2020 - A  study published in the journal mBio suggests that the measles, mumps, rubella (MMR) vaccine could reduce the inflammation associated with COVID-19 disease. These researchers stated: 'There is mounting evidence that lives attenuated vaccines provide nonspecific protection against lethal infections unrelated to the target pathogen of the vaccine by ... inducing “trained” nonspecific innate immune cells for improved host responses against subsequent infections.'

May 20, 2020 - The MMR Vaccine Appears to Confer Strong Protection from COVID-19: Few Deaths from SARS-CoV-2 in Highly Vaccinated Populations. Published epidemiological data suggest a correlation between patients who receive measles-rubella-containing vaccines such as the commonly available MMR vaccine and reduced COVID-19 death rate. Similar observations were recently noted in a Cambridge Study by Young et al., who noted protein homology between the COVID-19 virus and the rubella virus, corroborating this report's evidence. The epidemiologic associations suggest that a measles-rubella-containing vaccine, as currently produced, may be protective against severe disease and death from COVID-19 exposure.

According to a report published Monday, May 18, 2020 - Routine vaccinations for young children in the U.S. fell during the first half of this year as more Americans skipped routine doctor visits due to the coronavirus pandemic by the Centers for Disease Control and Prevention. 

May 3, 2020 - The report MMR Vaccine Link to COVID-19: Fewer Deaths and Milder Cases from SARS-CoV-2 in Measles-Rubella Vaccinated Populations reveals that the MMR vaccine launched in 1971 (49 years ago) could explain why those 49 and under are much less likely to have bad outcomes from COVID-19 compared to those 50 and over, according to report co-contributor Dr. Larry P. Tilley, an Advisory Board Member of World Organization.

April 28, 2020 – Public health officials in Mexico have identified a measles virus outbreak in various states in Mexico.

April 27, 2020 – A recent review of the existing evidence on the safety and effectiveness of measles-related vaccines supports their continued use for mass immunization worldwide.

April 10, 2020 - A non-peer-reviewed study stated, 'As an initial test of this hypothesis, we identified that 1.) age groups that most likely lack MMR vaccine-induced immunity had the poorest outcome. COVID-19, and 2.) COVID-19 disease burden correlates with rubella antibody titers, potentially induced by SARS-CoV2 homologous sequences. Therefore, we propose that vaccination of ‘at risk’ age groups with an MMR vaccination merits further consideration as a time appropriate and safe intervention.'

Measles, Mumps, and Rubella FAQs

Ask the Experts at Immuninize Action Coalition 

M-M-R II Vaccine Clinical Trials

Clinical Trial NCT01702428: Consistency Study of GlaxoSmithKline (GSK) Biologicals' MMR Vaccine (209762) (Priorix) Comparing Immunogenicity and Safety to Merck & Co., Inc.'s MMR Vaccine (M-M-R II), in Children 12 to 15 Months of Age.

ClinicalTrial NCT04333732: CROWN CORONATION: COVID-19 Research Outcomes Worldwide Network for CORONAvirus prevenTION (CROWN CORONA). CROWN CORONATION is an international, Bayesian platform adaptive, randomized, placebo-controlled trial assessing candidate interventions' effectiveness in preventing COVID-19 disease in healthcare workers. Randomization will be stratified by age (<50 and ≥50) and site. Participants will be healthcare workers at risk of contracting SARS-CoV-2.