Among 4,497 children 12 to 23 months old who received the frozen formulation of ProQuad (Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live), most adverse events occurred in a similar or lower percentage of children as compared with 2,038 children who received MMR and the varicella virus vaccine concomitantly at separate injection sites. A rash at the injection site was more common among recipients of ProQuad (2.3% vs. 1.5%). An injection site reaction with symptoms such as pain/soreness/tenderness (22 to 30.4%), erythema (14.4 to 18%), swelling (8.4 to 9.2%), and ecchymosis (1.5%) was the most common adverse event noted in trials. Extravasation has also been reported during postmarketing use of the drug.[31531]

Among children 12 to 23 months old or 4 to 6 years old who received ProQuad brand of Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine (ProQuad) most adverse events occurred in a similar percentage of children as compared with children who received MMR and varicella virus vaccine concomitantly at separate injection sites. Specifically, irritability was noted in 1 to 6.7% of ProQuad recipients and in 1 to 6.7% of MMR and varicella virus vaccine recipients. Diarrhea was noted in 0.8 to 1.3% of ProQuad recipients and in 1.3% of MMR and varicella virus vaccine recipients. Fewer ProQuad recipients ages 12 to 23 months had irritability (2.4%) or diarrhea (0.6%) after the second dose. Rhinorrhea was noted in 0.5 to 1.1% of ProQuad recipients and in 0.5% of MMR and varicella virus vaccine recipients. Cough was noted in 1.3% of ProQuad recipients and in 0.5% of MMR and varicella virus vaccine recipients. Headache was noted in 0.8% of ProQuad recipients and in 1.6% of MMR and varicella virus vaccine recipients. Vomiting was noted in 0.3 to 1.2% of ProQuad recipients and in 0.5% of MMR and varicella virus vaccine recipients. Drowsiness (somnolence) was also noted in 1.2% of ProQuad recipients, and nausea may be observed. During postmarketing use of ProQuad, cases of agitation, apathy, nervousness, and hypersomnia were reported. Due to the voluntary nature of postmarketing reports, neither a frequency nor a definitive causal relationship can be established.[31531]

Cases of transient thrombocytopenia have been reported within 4 to 6 weeks after vaccination with measles, mumps, and rubella vaccine. Thrombocytopenia, aplastic anemia, epistaxis, lymphadenitis, and regional lymphadenopathy have been reported with the postmarketing use of measles virus; mumps virus; rubella virus; varicella virus vaccine.[31531]

Induction of a subclinical infection with attenuated varicella virus particles is expected after measles virus; mumps virus; rubella virus; varicella virus vaccine, live (MMRV) receipt. The vaccine virus in MMRV may establish latency of varicella-zoster virus in immunocompetent patients, with the potential for later development of herpes zoster. Varicella and herpes zoster infections with the vaccine strain have been noted in vaccine recipients during postmarketing experience. Postmarketing experience suggests that transmission of varicella infection, including disseminated disease, may occur rarely between healthy vaccinees who may or may not develop a varicella-like rash and in both healthy and high-risk contacts. Based on effective donor screening and product manufacturing processes, MMRV vaccine carries an extremely remote risk of transmission of viral infection or disease. A theoretical risk for transmission of Creutzfeldt-Jakob disease also is considered to be extremely remote. Among children 12 to 23 months old who received ProQuad brand of MMRV vaccine, upper respiratory tract infection (1.2% to 1.4%) occurred in a similar percentage of children as compared with children who received MMR and varicella virus vaccine concomitantly at separate injection sites (1% to 1.1%). Naso-pharyngitis was noted in 0.3% of ProQuad recipients and 1% of MMR and varicella virus vaccine recipients 4 to 6 years of age. Infections and symptoms of an infection reported during postmarketing use of the drug include atypical measles, bronchitis, candidiasis, epididymitis, herpes simplex, herpes zoster, influenza, orchitis, parotitis, pneumonia, pneumonitis, pulmonary congestion, rhinitis, sinusitis, sneezing, throat irritation, and skin infections such as cellulitis and impetigo. Due to the voluntary nature of postmarketing reports, neither a frequency nor a definitive causal relationship can be established.[31531]

Among young children 12 to 23 months old who received Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live (ProQuad), most adverse events (including varicella-like rash, rash (unspecified), viral exanthema) occurred in a similar percentages of children as compared with children who received MMR and Varivax concomitantly at separate injection sites. Specifically, a varicella-like or vesicular rash was noted in 1.2 to 2.1% of ProQuad recipients and in 2.2% of MMR and varicella virus vaccine recipients. A rash (unspecified) was noted in 1.2 to 1.6% of Proquad recipients and in 1.4% of MMR and varicella virus vaccine recipients. Viral exanthema was noted in 1.2% of ProQuad recipients and in 1.1% of MMR and varicella virus vaccine recipients. A measles-like rash occurred in 3 to 5.1% of ProQuad recipients and in 2.1% of MMR and varicella virus vaccine recipients. Fewer ProQuad recipients had rashes after the second dose: 0.9% had a measles-like or a rubella-like rash, 0.1% had a varicella-like rash, and 0.6% had a rash (unspecified). The measles, mumps, and rubella infection is noncommunicable, but varicella could be transmitted from vaccinated patients to susceptible individuals during the first 6 weeks after vaccination. Vaccine recipients who develop a varicella-like rash should avoid contact with varicella-susceptible persons for at least 6 weeks after vaccination.[31531]

Anaphylactoid reactions, anaphylactic shock, angioneurotic edema (angioedema), facial edema, peripheral edema, acute hemorrhagic edema of infancy, pruritus, bronchospasm, wheezing, erythema multiforme, Henoch-Schonlein purpura, panniculitis, photosensitivity (sunburn), purpura, and Stevens-Johnson syndrome have been noted in Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live recipients during postmarketing experience or with vaccine components during clinical trials or postmarketing.[31531]

Encephalitis, measles inclusion body encephalitis, encephalopathy, acute disseminated encephalomyelitis (ADEM), aseptic meningitis, and meningitis have been reported during the postmarketing surveillance period for measles virus; mumps virus; rubella virus; varicella virus (MMRV) vaccine. Although not reported with MMRV vaccination, cases of encephalitis or meningitis caused by vaccine strain varicella virus have been reported in immunocompetent individuals months to years after vaccination with varicella virus vaccine. Reported cases were commonly associated with preceding or concurrent herpes zoster rash. Subacute sclerosing panencephalitis (SSPE) has also been reported in the postmarketing surveillance period. Measles inclusion body encephalitis, pneumonitis, and death as a direct consequence of disseminated measles vaccine virus infection have been reported in immunocompromised patients inadvertently vaccinated with measles-containing vaccine.[31531]

Among young children 12 to 23 months old who received ProQuad brand of Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live, a fever of at least 102 degrees F occurred in 15.3 to 21.5% of patients as compared with 14.9% of children who received MMR and varicella virus vaccine concomitantly at separate injection sites. A fever occurred in 2.5% of children 4 to 6 years of age who received ProQuad and in 4.1% of children who received MMR and varicella virus vaccine concomitantly at separate injection sites. Among children 12 to 23 months old who have not been previously vaccinated against measles, mumps, rubella, or varicella or who do not have a history of the wild-type infections, administration of ProQuad (dose 1) is associated with higher rates of fever and febrile seizures 5 to 12 days after vaccination as compared with receipt of both MMR and varicella virus vaccine administered separately for dose 1 (RR 1.89; 95% CI, 1.67, 2.15). As determined from a postmarketing observational study in 31,298 children who had neither been vaccinated against measles, mumps, rubella, or varicella nor had a history of the wild-type infections, febrile seizures were noted 5 to 12 days after vaccination in 0.7 per 1,000 recipients of ProQuad. The RR of a febrile seizure after dose 1 of ProQuad was 2.20, 95% CI, 1.04, 4.65. In contrast, in a historical age and gender matched control group of concurrent MMR and varicella virus vaccine recipients, the incidence was 0.32 per 1,000 recipients. In the 0 to 30 day time period after vaccination, the incidence of febrile seizures with ProQuad (1.41 per 1,000) was not greater than that observed in children receiving MMR andvaricella virus vaccine concomitantly (1.28 per 1,000). For the second dose, no case of febrile seizure was observed during the 5 to 12 day post-vaccination time period among ProQuad recipients. In addition, no specific safety concern was noted from an analysis of data from more than 25,000 children mostly 4 to 6 years old who received ProQuad as a second dose. However, the risk of febrile seizure after dose 2 has not been evaluated in a clinical study comparing the incidence rate after ProQuad with the incidence rate after concomitant MMR and Varivax.[31531] An increased risk of febrile seizures with ProQuad in the early period after vaccination was also noted in preliminary results from a CDC observational study. A febrile seizure 7 to 10 days after vaccination with ProQuad was noted in 9 per 10,000 vaccinations whereas the incidence was 4 per 10,000 vaccinations among recipients of concurrent MMR and varicella virus vaccine. The Advisory Committee on Immunization Practices (ACIP) recommends that either the MMR vaccine and varicella vaccine or ProQuad may be used for the first dose of measles, mumps, rubella, and varicella vaccines at age 12 to 47 months. However, the CDC recommends that MMR vaccine and varicella vaccine should be administered for the first dose in this age group unless the parent or caregiver expresses a preference for ProQuad. Discuss the benefits and risks of both vaccination options with the parents or caregivers. For the second dose of measles, mumps, rubella, and varicella vaccines at 15 months to 12 years of age and for the first dose at age 48 months or older, use of ProQuad generally is preferred over separate injections of MMR vaccine and varicella vaccine.[52359] Report any clinically significant adverse events after immunization to the Vaccine Adverse Event Reporting System by calling 800-822-7967.

Arthritis, arthralgia, musculoskeletal pain, and myalgia have been identified during postmarketing use of the components of ProQuad or ProQuad. Joint symptoms such as arthralgia, arthritis, and myalgia are associated with the rubella component of the measles virus; mumps virus; rubella virus; varicella virus vaccine live. Joint symptoms are usually transient; only rarely have vaccine recipients developed chronic joint symptoms. Among susceptible persons, arthralgia and transient arthritis occur more frequently among adults than among children and more frequently among postpubertal females than among males. In women, incidence rates for arthritis and arthralgia are generally higher (12 to 26%) than those seen in children (0% to 3%), and the reactions tend to be more marked and of longer duration. Symptoms may persist for a matter of months or on rare occasions for years. In adolescent girls, the reactions appear to be intermediate in incidence between those seen in children and in adult women. Even in women older than 35 years, these reactions are generally well tolerated and rarely interfere with normal activities. When acute joint symptoms do occur, they generally begin 1 to 3 weeks after vaccination, persist for 1 day to 3 weeks, and rarely recur. Tell postpubertal females about the frequent occurrence of generally self-limited arthralgia and/or arthritis beginning 2 to 4 weeks after vaccination.

Acute disseminated encephalomyelitis (ADEM), ataxia, Bell’s palsy, Guillain-Barre syndrome, cerebrovascular accident, dizziness, abnormal dreams, ocular palsies, paresthesias, polyneuritis, polyneuropathy, syncope, transverse myelitis, and tremor have been noted without regard to causality postmarketing with measles virus; mumps virus; rubella virus; varicella virus vaccine live (ProQuad) and/or in clinical studies and/or postmarketing with the component vaccines.[31531] Although cases of Guillain-Barre syndrome (GBS) have been reported after administration of MMR vaccination, a causal relationship has not been established. Recent mass vaccination campaigns that involved approximately 8 million doses of measles-rubella vaccine in the UK and more than 70 million doses of measles vaccine in Latin America demonstrated no increased incidence of GBS over baseline rates. Expert committees at the Institute of Medicine (IOM) have reviewed available evidence concerning the causal relationship between MMR vaccination and various adverse events. Although vasculitis, otitis media, conjunctivitis, ocular palsies, Guillain-Barre syndrome, and ataxia have been reported after administration of MMR or its component vaccines and are listed in the manufacturer's package insert, the IOM has determined that no causal relationship has been established between these events and MMR vaccination.[23937] In addition, evidence does not support a causal association of measles-containing vaccine with risk for Crohn's disease or other inflammatory bowel disease. Cases of aseptic meningitis have been reported to VAERS after measles, mumps, and rubella vaccination. Although a causal relationship between the Urabe strain of mumps vaccine and aseptic meningitis has been shown, there is no evidence to link Jeryl Lynn mumps vaccine to aseptic meningitis.

Cases of otalgia, hearing loss, ocular irritation, eyelid edema (blepharedema), retinitis, necrotizing retinitis (in immunocompromised individuals), optic neuritis, and retrobulbar neuritis have been reported during postmarketing use of measles virus; mumps virus; rubella virus; varicella virus vaccine live (ProQuad). Due to the voluntary nature of postmarketing reports, neither a frequency nor a definitive cause relationship can be established.[31531]

Gastrointestinal adverse events reported during postmarketing use of measles virus; mumps virus; rubella virus; varicella virus vaccine live (ProQuad) include abdominal pain, flatulence, hematochezia, and oral ulceration. Due to the voluntary nature of postmarketing reports, neither a frequency nor a definitive causal relationship can be established.[31531]

Measles and mumps viruses are cultured from chick embryos. Patients with a history of egg hypersensitivity may be more likely to develop an allergic reaction if given the vaccine. In persons allergic to eggs, the risk for serious allergic reactions after administration of measles- or mumps-containing vaccines is extremely low. In a study of 54 children with documented egg allergy, a single 0.5 mL subcutaneous dose of the MMR vaccine was administered safely despite the confirmation of egg allergy with a food challenge.[24433] Thus, according to the CDC, skin testing is not required before administering MMR to persons allergic to eggs.[23937] Data indicate that most anaphylactic reactions to measles- and mumps-containing vaccines are not associated with hypersensitivity to egg antigens but to other components of the vaccines. Carefully evaluate the risk to benefit ratio before vaccinating an individual with an egg hypersensitivity. Treatment of an anaphylactoid reaction may be necessary.

Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live is preservative-free, but it does contain trace amounts of neomycin from the manufacturing process and should not be given to anyone with a history of immediate-type neomycin hypersensitivity (e.g., anaphylactoid reactions). Contact dermatitis from neomycin exposure is not a contraindication for vaccine receipt. If vaccine receipt is necessary for a patient with a history of anaphylactic reactions to neomycin, consult an allergist or immunologist and be prepared to treat an anaphylactoid reaction. Patients with a history of hypersensitivity to any component of the vaccine, including gelatin hypersensitivity or albumin hypersensitivity, should also not receive Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live. Each dose of the Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live contains 11 mg of hydrolyzed gelatin as a stabilizer and 0.31 mg of human albumin. With any biologic product, the prescriber or health care professional should take precautions to prevent allergic reactions. The health care professional should have immediate availability of epinephrine 1 mg/mL injection and other agents used in the treatment of severe anaphylaxis in the event of a serious allergic reaction to the vaccine. Prior to the administration of the vaccine, the health care personnel should inform the parent, guardian, or responsible adult of the benefits and risks to the patient. This should include the provision of the vaccine information statement from the manufacturer. The responsible adult should report any adverse reaction following vaccine administration to the health care provider. The U.S. Department of Health and Human Services has established a Vaccine Adverse Event Reporting System (VAERS) to accept all reports of suspected adverse events after the administration of any vaccine. This includes, but is not limited to, the reporting of events required by the National Childhood Vaccine Injury Act of 1986. The toll-free number for VAERS is 1-800-822-7967.

Do not give the measles virus; mumps virus; rubella virus; varicella virus (MMRV) via intravenous administration. The vaccine is for subcutaneous or intramuscular administration only.[31531]

Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live should not be given to patients with moderate or severe fever (> 101.3 degrees F) or a severe respiratory infection. Minor illness, such as a mild upper respiratory tract infection or diarrhea with or without low grade fever, does not preclude vaccine administration. Patients with active, untreated tuberculosis should not be given the vaccine, as there are no data on the effects of the safety of vaccination in these patients. The effect of measles virus vaccines on children with untreated tuberculosis is unknown. Exacerbation of tuberculosis after live measles virus vaccination in children who are being treated for tuberculosis has not been noted.

Recommendations and precautions for patients with immunosuppression are complex, but the measles virus; mumps virus; rubella virus; varicella virus (MMRV) live vaccine is contraindicated in any person with a primary immunodeficiency state (i.e., severe combined immunodeficiency (SCID), IgA deficiency, hypogammaglobulinemia, agammaglobulinemia, or dysgammaglobulinemia) or an acquired immunodeficiency state.[31531] [52359] Measles inclusion body encephalitis, pneumonitis, and death as a direct consequence of disseminated measles vaccine virus infection have been reported in immunocompromised patients inadvertently vaccinated with measles-containing vaccine; additionally, disseminated mumps, rubella, and varicella virus infection has occurred in immunosuppressed patients who were inadvertently given a MMRV vaccine. In addition, although there is no confirmed evidence to indicate the rubella virus can be transmitted to susceptible persons in contact with the vaccinated patient, there is a theoretical risk. Excretion of small amounts of the live, attenuated rubella virus from the nose or throat has occurred in the majority of susceptive individuals 7 to 28 days after vaccination. A family history of congenital or hereditary immunodeficiency is also a contraindication for MMRV vaccine unless the immune competence of the potential vaccine recipient is demonstrated.[31531] [43236] Vaccine recipients should avoid close association with susceptible high-risk individuals for 6 weeks. High-risk individuals include immunocompromised individuals, pregnant women without a documented history of chickenpox or laboratory evidence of prior infection, newborn infants of mothers without documented history of chickenpox or laboratory evidence of prior infection, and all newborn infants born younger than 28 weeks gestation regardless of maternal varicella immunity. In circumstances where contact with high-risk individuals is unavoidable, weigh the potential risk of transmission of vaccine virus against the risk of acquiring and transmitting natural varicella virus.[31531] The vaccine should also not be administered to those with cellular immune deficiency or those patients on immunosuppressive therapy such as high-dose corticosteroid therapy. Vaccination with MMRV vaccine can result in a more extensive vaccine-associated rash or disseminated disease in these patients. However, corticosteroid therapy usually is not a contraindication to administering live-virus vaccines when administration is short-term (less than 2 weeks); a low-to-moderate dose (less than 2 mg/kg of body weight or 20 mg/day of prednisone or equivalent for persons who weigh more than 10 kg when administered for less than 2 weeks); long-term, alternate-day treatment with short-acting preparations; maintenance physiologic doses (replacement therapy); or when administered topically (skin, eyes), inhaled, or by local injection. Healthcare providers should wait at least 1 month after discontinuation of high-dose corticosteroid therapy given for more than 2 weeks before administering MMRV vaccine.[43236] The vaccine is also contraindicated in patients with blood dyscrasias or any neoplastic disease that causes bone marrow suppression or affects the lymphatic system such as leukemia or lymphoma, including patients currently receiving chemotherapy or radiation therapy.[31531] [43236] [52359] Patients with leukemia, lymphoma, or other malignancies whose disease is in remission and whose chemotherapy or radiation therapy has been terminated for at least 3 months can receive live-virus vaccines.[43236]

The measles virus; mumps virus; rubella virus; varicella virus (MMRV) vaccine is contraindicated in pregnancy or people who may become pregnant in the next 4 weeks. Educate individuals of reproductive capacity on the importance of prevention of pregnancy for 3 months after vaccination. Acquiring wild-type measles during pregnancy has reportedly led to increased rates of spontaneous abortion, stillbirth, congenital defects, and prematurity. Wild-type mumps virus infection during the first trimester of pregnancy may increase the rate of spontaneous abortion. The mumps vaccine virus has been shown to infect the placenta, but there is no evidence that it causes congenital malformation or disease in the fetus or infant. Wild-type varicella can sometimes cause congenital varicella infection. Pregnant individuals infected with wild-type rubella virus are at increased risk of miscarriage or stillbirth, and their neonates are at risk for Congenital Rubella Syndrome (CRS). CRS in the infant can lead to eye problems (cataracts, glaucoma, retinitis), congenital heart defects, hearing loss, microcephaly, and intellectual disabilities. Between 1971 and 1989, a Vaccine in Pregnancy registry tracked 1,221 individuals who inadvertently received rubella virus vaccines within 3 months before or after conception. No increase in fetal abnormalities or cases of CRS was observed. From 1978 to 2018, postmarketing data followed 425 individual pregnancies prospectively who inadvertently received measles, mumps, and rubella vaccine. Among these, there were 16 cases of major birth defects, 4 cases of fetal death, 50 miscarriages, but no abnormalities or cases of CRS were reported. However, one case of CRS has been reported during postmarketing experience. A pregnant individual was inadvertently administered a measles, mumps, rubella virus containing vaccine from an unknown manufacturer at 5 weeks gestation. If vaccination is needed, vaccinate individuals immediately after delivery.[31531] [65107]

According to the CDC, live-virus vaccines administered to a lactating woman do not affect the safety of breast-feeding for women or their infants. The rubella vaccine virus may be excreted in human milk; however, the virus usually does not infect the infant. If infection does occur, it is well tolerated because the virus is attenuated. The varicella vaccine virus has not been found in human milk. The ability of either the measles or mumps vaccine virus to be secreted in human milk is unknown. The manufacturer of the combination vaccine states that the it should not be administered to breast-feeding women because it is not known whether some components of the vaccine are excreted into breast milk and that the rubella vaccine virus has been found in the breast milk of lactating women who were immunized with live attenuated rubella vaccine.[31531] In breast-feeding infants with serological evidence of rubella infection, none exhibited severe disease; however, one exhibited mild clinical illness typical of acquired rubella. There are no data to suggest that passive transfer of antibodies in human milk can affect the efficacy of live-virus vaccines. Breast fed infants should be vaccinated according to the recommended schedule.[30319] [43236]

At this time, no clinical data are available on the immunogenicity, efficacy, and safety of Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live in infants; vaccination of patients < 12 months of age is not recommended. The use of the vaccine is also not indicated for anyone over 12 years of age including geriatric patients.

Children with a personal or family history of a seizure disorder or a personal history of cerebral injury may be at an increased risk of developing febrile seizures after Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine administration. The risk of this complication, however, appears to be low. Febrile seizures also occur commonly among children in whom measles disease develops.

Patients with thrombocytopenia or patients who developed thrombocytopenia after a measles, mumps, and rubella-containing vaccine may not be appropriate candidates for the Measles virus; Mumps virus; Rubella virus; Varicella virus vaccine, live. Transient thrombocytopenia has been reported within 4 to 6 weeks after vaccination. Consider the potential risk and benefit of vaccination in patients with thrombocytopenia or in those who experienced thrombocytopenia after vaccination with a previous dose of a measles, mumps, and rubella-containing vaccine.[31531]

Measles virus; mumps virus; rubella virus; varicella virus vaccine, live contains albumin, a derivative of human blood. As with other products derived from or purified with human blood components, the remote possibility of contamination with Creutzfeldt-Jakob disease (CJD) and other viral infection exists in patients receiving the vaccine. Screening plasma donors for prior exposure to certain viruses, testing for the presence of viruses, and inactivating and/or reducing viruses has reduced the risk of transmission of infectious agents. Although there is a theoretical risk for transmission of CJD or viral disease, no cases have been identified that were associated with the use of albumin.[31531]

Persons living with human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) should not receive the MMRV vaccine.[43236] [52359] Pediatric persons living with HIV who have met criteria for vaccination (age specific CD4 percentages 15% or more) should receive the single antigen varicella vaccine along with the MMR vaccine, and not the combination MMRV vaccine.[34366] [43236]

The measles, mumps, rubella, and varicella (MMRV) vaccine may result in temporary suppression of tuberculin reactivity causing a laboratory test interference with a tuberculin skin test. Therefore, administer a tuberculin skin test either before, simultaneously with, or at least 4 to 6 weeks after MMRV vaccination to avoid false-negative results.[31531] Additionally, syndromic polymerase chain reaction (PCR) panels may incorrectly identify a measles infection if a patient recently received an MMR vaccine. Approximately 5% of patients experience a rash after the MMR vaccine; approximately 1% of syndromic panels report a positive measles result after MMR vaccination. Patients identified with a positive result were pediatric patients without known measles risk who, in most cases, received the vaccine less than 3 weeks beforehand. Inclusion of measles virus in syndromic PCR panels can result in incidental detection of measles vaccines. Health care providers should assess clinical features and vaccine history after a positive test.[70504]