Rubella is a viral infection that may cause adenopathy, rash, and sometimes constitutional symptoms, which are usually mild and brief. Infection during early pregnancy can cause spontaneous abortion, stillbirth, or congenital defects. Diagnosis is usually clinical. Cases are reported to public health authorities. Treatment is usually unnecessary. Vaccination is effective for prevention.
(See also Congenital Rubella.)
Rubella is caused by an RNA virus, which is spread by respiratory droplets through close contact or through the air. Patients can transmit rubella from 7 days before a rash appears until 15 days after onset of the rash; the period of greatest risk is from a few days before the rash appears to 7 days after onset of the rash. Some patients are asymptomatic, but they can transmit the virus. Congenitally infected infants may transmit rubella for many months after birth.
Rubella is less contagious than measles. Immunity appears to be lifelong after natural infection. However, in unvaccinated populations, 10 to 15% of young adults have not had childhood infection and are susceptible.
At present, incidence in the United States is extremely low because of routine childhood vaccination; all cases since 2004 have been imported.
Symptoms and Signs of Rubella
Many cases are mild. After a 14- to 21-day incubation period, a 1- to 5-day prodrome, usually consisting of low-grade fever, malaise, conjunctivitis, and lymphadenopathy, occurs in adults but may be minimal or absent in children.
Tender swelling of the suboccipital, postauricular, and posterior cervical nodes is characteristic.
There is pharyngeal injection at the onset.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
The rash that develops subsequently is similar to that of measles but is less extensive and more evanescent; it is often the first sign in children. It begins on the face and neck and quickly spreads to the trunk and extremities. At onset, a blanching, macular erythema may appear, particularly on the face. On the 2nd day, the rash often becomes more scarlatiniform (pinpoint) with a reddish flush. Petechiae form on the soft palate (Forchheimer spots), later coalescing into a red blush. The rash lasts 3 to 5 days.
Constitutional symptoms in children are absent or mild and may include malaise and occasional arthralgias.
Adults usually have few or no constitutional symptoms but occasionally have fever, malaise, headache, stiff joints, transient arthritis, and mild rhinitis. Fever typically resolves by the 2nd day of the rash.
Encephalitis has occurred rarely during large military outbreaks. Complete resolution is typical, but encephalitis is occasionally fatal.
Thrombocytopenic purpura and otitis media occur rarely.
Diagnosis of Rubella
History and physical examination
Serologic testing
Rubella is suspected in patients with characteristic adenopathy and rash.
Laboratory diagnosis is necessary for pregnant women, patients with encephalitis, and neonates. Also, laboratory evaluation is strongly encouraged for all suspected cases of rubella for public health purposes. A ≥ 4-fold rise between acute and convalescent (4 to 8 weeks) antibody titers confirms the diagnosis, as can serum rubella IgM antibody testing.
Detection of viral RNA by reverse transcription–polymerase chain reaction testing of throat, nasal, or urine specimens may also be done to confirm the diagnosis; genotype analysis is useful in epidemiologic investigations.
Differential diagnosis includes measles, scarlet fever, secondary syphilis, drug rashes, erythema infectiosum, and infectious mononucleosis as well as echovirus and coxsackievirus infections (see table Some Respiratory Viruses). Infections with enteroviruses and parvovirus B19 (erythema infectiosum) may be clinically indistinguishable.
Some of these conditions can be distinguished from rubella as follows:
Measles: Rubella is differentiated from measles by the milder, more evanescent rash, milder and briefer constitutional symptoms, and absence of Koplik spots, photophobia, and cough.
Scarlet fever: Within a day of onset, scarlet fever usually causes more severe constitutional symptoms and pharyngitis than does rubella.
Secondary syphilis: In secondary syphilis, adenopathy is not tender, and the rash is usually prominent on the palms and soles. Also, laboratory diagnosis of syphilis is usually readily available.
Infectious mononucleosis: Infectious mononucleosis can be differentiated by its more severe pharyngitis, more prolonged malaise, and atypical lymphocytosis and with Epstein-Barr virus antibody testing.
Treatment of Rubella
Supportive care
Treatment of rubella is symptomatic.
No specific therapy for encephalitis is available.
Prevention of Rubella
Vaccination with live-attenuated virus vaccine containing measles, mumps, and rubella (MMR) (see also Childhood Vaccination Schedule) is given routinely to children in most nations that have a robust health care system.
Two doses are recommended:
The first dose at age 12 to 15 months
The second dose at age 4 to 6 years
Infants immunized at < 1 year of age still require 2 additional doses given after their first birthday.
MMR vaccination generally provides lasting immunity (1). The effectiveness of the MMR vaccine in preventing rubella in children was 93 to 97% after one dose and 100% after two doses, based on observational studies (2).
To prevent congenital rubella, unvaccinated patients who could become pregnant should receive one dose of the MMR vaccine and then wait 4 weeks before trying to conceive. For patients vaccinated during childhood, many clinicians do preconceptual serologic testing for rubella IgG to confirm immunity, because some people do not develop immunity after initial immunization. Once rubella immunity is confirmed, patients do not need to be tested again before subsequent pregnancies.
The vaccine causes mild or inapparent, noncommunicable infection. Fever > 38° C occurs 5 to 12 days after inoculation in 5 to 15% of vaccinees and can be followed by a rash. Central nervous system reactions are exceedingly rare. The MMR vaccine does not cause autism.
MMR is a live vaccine and is contraindicated during pregnancy.
See MMR Vaccine for more information, including indications, contraindications and precautions, dosing and administration, and adverse effects.
Prevention references
1. McLean HQ, Fiebelkorn AP, Temte JL, Wallace GS; Centers for Disease Control and Prevention: Prevention of measles, rubella, congenital rubella syndrome, and mumps, 2013: Summary recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 62(RR-04):1–34, 2013.
2. Di Pietrantonj C, Rivetti A, Marchione P, et al: Vaccines for measles, mumps, rubella, and varicella in children. Cochrane Database Syst Rev 4(4):CD004407, 2020. doi: 10.1002/14651858.CD004407.pub4
Key Points
Rubella causes a scarlatiniform rash and often low-grade fever, malaise, conjunctivitis, and lymphadenopathy (characteristically involving the suboccipital, postauricular, and posterior cervical nodes).
Most cases are mild and complications are few except for rare cases of encephalitis and the risk during early pregnancy that infection can cause spontaneous abortion, stillbirth, or congenital defects.
Laboratory diagnosis is strongly encouraged for all suspected cases for public health purposes; serologic or reverse transcription–polymerase chain reaction testing can be done.
Screen women of childbearing age for rubella antibodies and immunize those susceptible, providing conception is prevented for ≥ 28 days afterwards.
Vaccination is contraindicated during pregnancy.
