Differences Between Measles and Rubella
Measles and rubella are distinct viral diseases with different clinical presentations, complications, and public health implications, despite both causing rash illnesses.
Clinical Presentation
Measles (Rubeola)
- Characterized by a prodrome of high fever, cough, coryza (runny nose), and conjunctivitis followed by a maculopapular rash that begins on the face and spreads downward 1
- Incubation period averages 10-12 days from exposure to prodrome and 14 days from exposure to rash 1
- Koplik spots (small white spots on a red background inside the mouth) appear during the prodrome and are pathognomonic for measles 1
- Rash typically lasts 5-6 days and may become confluent 1
Rubella (German Measles)
- Characterized by a milder presentation with low-grade fever, lymphadenopathy (particularly postauricular and suboccipital), and malaise 2, 3
- Incubation period ranges from 12 to 23 days 2
- Rash is scarletiniform, erythematous, and sometimes pruritic; it classically begins on the face, becomes generalized within 24 hours, and disappears within 3 days 3, 4
- Subclinical infection occurs in 25-50% of rubella cases 2, 3
Contagiousness
Measles
- Highly contagious respiratory disease transmitted through direct contact and airborne spread 1
- Patients are contagious from 4 days before to 4 days after rash onset 1
Rubella
- Less contagious than measles 2
- Period of maximal communicability extends from a few days before to 7 days after rash onset 2, 3
- Virus is present in nasopharyngeal secretions, blood, feces, and urine during clinical illness 5
Complications
Measles Complications
- Diarrhea is the most common complication, followed by middle ear infection and bronchopneumonia 1
- Encephalitis occurs in approximately 1 per 1,000 cases 1
- Death occurs in 1-2 per 1,000 reported cases in the United States, primarily from pneumonia and acute encephalitis 6, 1
- Subacute sclerosing panencephalitis (SSPE) is a rare but fatal late complication that appears years after infection 6, 1
Rubella Complications
- Arthralgia and arthritis are common complications, particularly in adult women (up to 70% of cases) 3, 4
- Encephalitis occurs at a lower rate than with measles (1 per 6,000 cases) 3
- Thrombocytopenia occurs at a rate of 1 per 3,000 cases 3
Teratogenic Effects
Measles in Pregnancy
- Associated with increased rates of premature labor, spontaneous abortion, and low birth weight infants 6, 1
- No definitive pattern of congenital malformations has been established 2
Rubella in Pregnancy (Congenital Rubella Syndrome)
- Primary concern is congenital rubella syndrome (CRS) when infection occurs during pregnancy, especially in the first trimester 2, 3
- Infection during the first 12 weeks of pregnancy results in congenital infection and/or miscarriage in 80-90% of cases 5
- Classic triad of CRS includes cataracts, congenital heart defects, and sensorineural deafness 3, 4
- Additional manifestations include microcephaly, mental retardation, growth retardation, hepatosplenomegaly, and purpuric skin lesions 3, 7
Laboratory Diagnosis
Measles
- Laboratory confirmation through measles-specific IgM antibody detection or significant rise in IgG antibody between acute and convalescent sera 2
- Viral isolation from appropriate clinical specimens 2
Rubella
- Laboratory confirmation through rubella-specific IgM antibody detection, significant rise in IgG antibody between acute and convalescent sera, or isolation of rubella virus 2
- Clinical diagnosis is unreliable due to the nonspecific nature of symptoms and similarity to other exanthematous illnesses 2, 3
Prevention
Both Diseases
- Both diseases are preventable through vaccination with the combined measles-mumps-rubella (MMR) vaccine 2, 1
- First dose recommended at 12-15 months and second dose at 4-6 years 2
- Healthcare workers should have acceptable evidence of measles and rubella immunity 2