Rubella, or German measles, is a contagious illness caused by the rubella virus, part of the Matonaviridae family. It most often affects children and young adults, but anyone who is not vaccinated can catch it. Symptoms are usually mild and may include a fine pink or red rash that starts on the face and spreads to the body, a mild fever, and swollen lymph nodes behind the ears or at the back of the neck. Some people may also experience joint pain, tiredness, or mild eye irritation.
Although rubella usually clears up on its own within a few days, it can be dangerous during pregnancy. In temperate climates, outbreaks were most common during spring and winter. The incubation period ranges from 13 to 23 days. If a woman becomes infected in early pregnancy, especially in the first three months, the virus can cause congenital rubella syndrome (CRS). CRS can lead to miscarriage, stillbirth, or serious birth defects, such as heart problems, cataracts, deafness, and developmental delays.
The virus spreads through tiny droplets released when an infected person coughs, sneezes, or talks. It can also pass from an infected mother to her baby during pregnancy through the placenta. People are most contagious in the week before and after the rash appears, making it easy for the disease to spread in the community.
Vaccination, particularly with the combined measles, mumps, and rubella (MMR) vaccine, has greatly reduced rubella worldwide. In countries with high vaccination rates, the disease has been eliminated or is very rare. However, outbreaks can still occur where vaccination coverage is low or health systems are weak.
Epidemiology
Before the introduction of vaccines, rubella caused large-scale epidemics every six to nine years in the United States and every three to five years in Europe. These outbreaks primarily affected children between the ages of five and nine.
The illness is often mild or even asymptomatic. Serious complications are rare but can occur, such as encephalitis (about one case per 5,000–6,000 infections) and thrombocytopenia (about one case per 3,000 infections). In pregnant women, especially during early pregnancy, infection carries a significant risk of miscarriage or congenital rubella syndrome.
Following the introduction of widespread vaccination in the late 1960s and early 1970s, rubella cases have declined sharply in countries with strong immunization programs. In many such countries, the disease has been eliminated or occurs only in isolated outbreaks.
The introduction of rubella-containing vaccines (RCV) has expanded significantly in recent decades. In 2012, only 132 out of 194 World Health Organization (WHO) member states had introduced RCV into their national immunization programs. By 2022, this number had increased to 175 countries. During the same period, global RCV coverage among infants rose from about 40% to roughly 68%.
In some regions, such as the Americas and Europe, vaccination coverage frequently exceeds 90%, supporting efforts toward complete elimination. The WHO Region of the Americas became the first region to be certified free of endemic rubella in 2015, with the last known cases occurring around 2009. By 2022, rubella elimination had been verified in 51% of countries worldwide, with 15 nations achieving elimination between 2019 and 2022.
Despite these gains, rubella remains a concern in parts of the world. An estimated 100,000 infants are born with CRS each year, particularly in Southeast Asia and Africa, where vaccination rates are still low. The COVID-19 pandemic disrupted both vaccination campaigns and disease surveillance, raising concerns about declining herd immunity and the possibility of disease resurgence.
As of 2022, around 25 million infants globally still lack access to rubella-containing vaccines, with the majority living in low-income or conflict-affected areas.
Historical Background
Rubella was first clearly described in the mid-18th century, with early accounts by Friedrich Hoffmann in 1740, followed by de Bergen in 1752 and Orlow in 1758. In 1814, George de Maton suggested distinguishing rubella from measles and scarlet fever. The name “rubella,” meaning “little red” in Latin, was introduced in 1866 by Henry Veale. The disease was formally recognized as a distinct illness in 1881.
In 1941, Australian ophthalmologist Sir Norman Gregg identified a link between rubella infection during early pregnancy and birth defects. This finding was a major milestone in recognizing congenital rubella syndrome (CRS), a condition that can cause serious complications in newborns.
The rubella virus was first isolated in 1938 by Hiro and Tosaka, who confirmed it as a filterable agent. Its molecular structure was later visualized in 1967 using electron microscopy.
One of the largest rubella outbreaks in U.S. history occurred between 1964 and 1965, with an estimated 12.5 million cases. The epidemic resulted in about 11,000 miscarriages or stillbirths and approximately 20,000 cases of CRS. Of these, 2,100 infants died, and many survivors suffered from deafness, blindness, or intellectual disabilities.
The first rubella vaccine, developed from the HPV-77 strain, was licensed in 1969. A more effective strain, RA 27/3, was adopted in the 1970s, and the combined measles, mumps, and rubella (MMR) vaccine was introduced in 1971. Vaccination campaigns in the United States led to a dramatic decline in rubella cases. By 1999, cases had fallen by 99% compared to 1969, dropping from 57,686 to just 271 reported cases.
Causes and Transmission
Rubella is caused by a specific virus that affects the respiratory system and can spread easily among people. It mainly transmits through airborne particles and direct contact with infected individuals. Certain groups face higher risk due to exposure or immune status.
Rubella Virus Characteristics
The rubella virus belongs to the genus Rubivirus within the family Matonaviridae (formerly classified under Togaviridae). It is an enveloped virus containing a single-stranded, positive-sense RNA genome. The viral envelope is studded with glycoproteins E1 and E2, which play a critical role in binding to host cell receptors and facilitating viral entry.
Following infection, the virus typically enters through the mucous membranes of the upper respiratory tract, where it begins to replicate in the epithelial cells. It then spreads to local lymphoid tissue before entering the bloodstream in a process known as viremia. This systemic spread allows the virus to reach multiple tissues, including the skin, where it causes the characteristic rash. The incubation period ranges from 13 to 23 days, and infected individuals often remain contagious before noticeable symptoms appear.
Although rubella is generally mild or asymptomatic in many cases, the virus remains present in respiratory secretions during the infectious period. Outside the human body, rubella virus is relatively unstable, surviving for only short periods in the environment. This instability means that close, direct contact is usually necessary for effective transmission, and indirect spread via contaminated surfaces is uncommon.
Modes of Transmission
Rubella spreads primarily through respiratory droplets expelled during coughing, sneezing, or normal conversation. These droplets can be inhaled directly or deposited onto the mucous membranes of the nose, mouth, or eyes of a nearby person. Direct contact with nasal or throat secretions from an infected individual is another route of transmission.
Because rubella symptoms are often mild or may not appear at all, individuals can unknowingly transmit the virus. This pre-symptomatic transmission is a key factor in community outbreaks.
A particularly serious form of transmission is vertical, or congenital, transmission. If a pregnant woman contracts rubella, the virus can cross the placenta and infect the developing fetus. This can result in congenital rubella syndrome (CRS), a condition associated with miscarriage, stillbirth, or severe birth defects.
The contagious period begins approximately seven days before the rash appears and continues for up to seven days after rash onset, making control measures challenging without high vaccination coverage.
High-Risk Populations
Pregnant women represent the most vulnerable group because of the severe consequences of congenital infection. The highest risk occurs when infection takes place during the first trimester, when organ development is most active. CRS can cause heart defects, cataracts, deafness, growth retardation, and developmental disabilities.
Unvaccinated children and young adults are also at elevated risk, especially in communities with low immunization coverage. In such populations, outbreaks tend to occur in school or community settings where close contact facilitates transmission.
Healthcare workers, childcare providers, and others in frequent contact with infected individuals are at increased occupational risk. Immunity acquired through vaccination or previous infection offers strong and usually lifelong protection, substantially reducing both the risk of illness and the potential for further spread.
Signs and Symptoms
Rubella presents with a range of symptoms that can vary from mild to more serious, depending on the individual. The period before symptoms appear and the potential complications highlight the disease’s clinical significance.
Signs and Symptoms
The illness often begins with a prodromal phase, characterized by a low-grade fever (typically below 38.5 °C or 101.3 °F), headache, and a general sense of discomfort or mild malaise. Some patients also report fatigue, loss of appetite, or mild joint discomfort during this stage. These early symptoms may be subtle or absent, particularly in younger children.
One of the hallmark features of rubella is a distinctive rash. This rash is usually pink to light red and consists of small, flat or slightly raised spots (maculopapular). It typically first appears on the face before spreading downward to the trunk, arms, and legs within about 24 hours. The rash usually lasts for two to three days and is generally not itchy, although mild itching can occur in some individuals. As the rash fades, it often disappears in the same order in which it appeared.
Another common sign is lymphadenopathy—swelling of the lymph nodes—especially in the posterior cervical (back of the neck) and occipital (base of the skull) regions. This swelling can appear up to a week before the rash and may persist for several weeks after other symptoms resolve. Other associated symptoms can include mild conjunctivitis (inflammation of the thin membrane covering the eye), a runny nose, and a mild cough.
Rubella infection can be asymptomatic in up to 50% of cases, particularly in children, meaning individuals may have no noticeable symptoms yet still be contagious.
Incubation Period
The incubation period for rubella—the time between exposure to the virus and the onset of symptoms—typically ranges from 14 to 21 days, with an average of about 17 days. During this period, the infected individual may feel completely well but can still harbor and later transmit the virus.
Viral shedding, the release of virus particles capable of infecting others, generally begins approximately seven days before the rash appears and continues for about seven days after the rash onset. This relatively long infectious period, combined with the possibility of symptom-free infection, allows rubella to spread unnoticed in communities, especially those with low vaccination coverage.
Complications
While rubella is generally a mild illness, it can lead to serious complications in certain populations. The most significant concern is infection during pregnancy, especially in the first trimester. In this period, the virus can cross the placenta and disrupt fetal development, leading to congenital rubella syndrome (CRS). CRS may cause severe birth defects, including sensorineural deafness, cataracts and other eye defects, congenital heart disease, microcephaly, developmental delays, and, in some cases, miscarriage or stillbirth.
In non-pregnant individuals, complications are uncommon but can occur. Rarely, rubella can lead to encephalitis (inflammation of the brain), which occurs in approximately one case per 6,000 infections. Another rare complication is thrombocytopenic purpura, a condition characterized by low platelet counts that can cause easy bruising and bleeding.
Arthritis and joint pain are more common in adolescent and adult women, affecting up to 70% of cases in these groups. These symptoms typically resolve within a few weeks but may persist longer in rare cases.
Congenital Rubella Syndrome
Congenital Rubella Syndrome (CRS) results from rubella virus infection during pregnancy, leading to severe fetal damage. It primarily affects the heart, eyes, ears, and brain, causing lifelong disabilities. Prevention hinges on vaccination and careful prenatal care.
Causes and Risk Factors
CRS develops when a pregnant woman contracts rubella and the virus crosses the placenta, entering the fetal bloodstream. The virus interferes with organ formation and cell growth during critical stages of embryonic and fetal development.
The timing of infection is the most important determinant of fetal risk. If rubella is contracted in the first 12 weeks of pregnancy, the risk of congenital abnormalities is extremely high—up to 85%. During this period, organogenesis (the formation of major organs) is taking place, making the fetus particularly vulnerable to viral damage. Infections between 13 and 16 weeks of gestation carry a lower risk, estimated at 30–50%, while infections later in pregnancy (after 20 weeks) rarely result in CRS, although mild effects can still occur.
Women who have not been vaccinated against rubella and who lack natural immunity from a prior infection are most susceptible. Risk increases with close contact with infected individuals, particularly in areas where rubella is still circulating.
Clinical Features in Newborns
CRS newborns frequently display a combination of symptoms, often presenting as a triad:
- Sensorineural deafness – the most common defect, often bilateral and irreversible.
- Ocular abnormalities – cataracts, congenital glaucoma, and pigmentary retinopathy (a type of retinal damage) are frequent.
- Congenital heart defects – most often patent ductus arteriosus (PDA) and pulmonary artery stenosis, which can cause heart murmurs and circulatory problems.
Other features include microcephaly (abnormally small head size), intrauterine growth retardation, hepatosplenomegaly (enlarged liver and spleen), bone radiolucencies, and skin lesions described as “blueberry muffin” spots due to dermal hematopoiesis.
Neurological complications such as intellectual disability, developmental delays, and behavioral disorders may emerge over time. Some infants with CRS appear normal at birth but develop hearing loss, vision impairment, or neurodevelopmental problems months or even years later.
Prevention During Pregnancy
The most effective prevention strategy for CRS is ensuring immunity before pregnancy. Vaccination with a rubella-containing vaccine, such as the combined measles, mumps, and rubella (MMR) vaccine, provides long-term protection. Because the rubella vaccine contains a live attenuated virus, it is contraindicated during pregnancy. For this reason, women planning pregnancy should be screened for rubella immunity and vaccinated at least one month before conception if non-immune.
During pregnancy, women should be tested for rubella immunity during the first antenatal visit. Those found to be non-immune should be counseled on avoiding exposure to rubella, especially during outbreaks, and advised on post-pregnancy vaccination. Preventive measures also include practicing good hygiene, such as frequent handwashing and avoiding close contact with individuals who have symptoms of rubella or who are known to be infected.
Diagnosis of Rubella
Diagnosis of rubella relies on specific clinical signs supported by targeted tests to confirm infection. It is crucial to accurately differentiate rubella from other similar conditions and identify cases early, especially in pregnant women.
Clinical Assessment
Rubella typically presents with mild, non-specific symptoms that can be easily overlooked. Common clinical features include a mild fever, generally below 38.5°C, and a maculopapular rash that begins on the face before spreading downward to the trunk and extremities. Swelling of the lymph nodes—especially those located behind the ears (postauricular), at the back of the head (occipital), and along the neck (posterior cervical)—is a hallmark finding.
Patients may also experience mild upper respiratory symptoms such as a runny nose or sore throat. The rash usually lasts for about three days, which is why rubella is sometimes called “three-day measles,” but in vaccinated individuals the rash may appear faint or even go unnoticed. Because these signs are non-specific and can occur with many other illnesses, laboratory confirmation is essential for a reliable diagnosis.
Laboratory Testing
Serologic Tests
The primary laboratory approach involves serologic testing. Detection of rubella-specific IgM antibodies indicates recent infection, as IgM becomes detectable within a few days after the onset of the rash and typically remains present for 4–8 weeks. However, a positive IgM test must be interpreted with caution because false positives can occur due to cross-reactivity with other viral infections, such as parvovirus B19 or Epstein–Barr virus, or due to the presence of rheumatoid factor. In cases of suspected congenital rubella, the presence of IgM antibodies in a newborn confirms in utero infection, since maternal IgM does not cross the placenta.
Rubella IgG antibody testing is used to determine a person’s immunity status or evidence of past infection. A fourfold or greater increase in IgG titers between acute and convalescent serum samples, collected 7–21 days apart, confirms recent infection. Conversely, stable high IgG levels suggest immunity acquired through prior infection or vaccination.
Molecular Detection
Reverse transcription polymerase chain reaction (RT-PCR) provides a highly sensitive and specific method for detecting rubella virus RNA in clinical specimens such as throat swabs, nasopharyngeal swabs, blood, or urine. This technique is most effective during the first week after the rash appears and is particularly valuable for confirming infection in outbreak situations, investigating clusters of cases, or diagnosing pregnant women when serologic results are inconclusive. In suspected congenital rubella cases, RT-PCR can also detect viral RNA in placental tissue, amniotic fluid, or newborn samples, sometimes for weeks to months after birth.
Virus Isolation
Although less commonly performed today due to the efficiency of molecular techniques, virus isolation remains possible in specialized laboratories. The rubella virus can be cultured from throat swabs or urine samples, although the process is more time-consuming and resource-intensive than RT-PCR.
Differential Diagnosis
Rubella can be easily mistaken for other illnesses, particularly in vaccinated individuals whose symptoms may be mild. Measles often presents more severely, with cough, conjunctivitis, Koplik spots, and a higher fever. Parvovirus B19 infection can produce a similar rash but is distinguished by a characteristic “slapped cheek” appearance in children.
Roseola, caused by human herpesvirus 6 (HHV-6), presents with a high fever that abruptly resolves before the rash appears. Scarlet fever, caused by group A streptococcus, is marked by a sandpaper-like rash, sore throat, high fever, and strawberry tongue.
Enteroviral infections may produce varied rash patterns, and drug reactions can mimic viral exanthems but generally lack accompanying viral symptoms. A thorough patient history—including vaccination records, recent travel, and exposure to confirmed cases—is essential for narrowing down the diagnosis.
Screening Recommendations
Routine rubella immunity screening is not generally recommended for the broader population outside of outbreak situations. However, screening plays a crucial role in women of childbearing age due to the serious consequences of congenital rubella.
All women should have their rubella immunity confirmed before conception or during the first prenatal visit, typically via rubella IgG testing. Non-immune pregnant women should be advised to avoid contact with infected individuals.
Because the rubella vaccine contains a live attenuated virus, it is contraindicated during pregnancy, but vaccination should be given in the postpartum period to protect future pregnancies.
Treatment and Management
Rubella treatment focuses primarily on alleviating symptoms and preventing complications. Care involves monitoring and supporting the patient while addressing specific medical needs.
Supportive Care Strategies
Treatment generally involves rest, adequate hydration, and the avoidance of strenuous physical activity to conserve energy during recovery. Fever and mild pain associated with rubella such as headache, sore throat, or arthralgia can be managed with over-the-counter analgesics and antipyretics, including acetaminophen (paracetamol) or ibuprofen. These medications do not affect the course of the illness but help improve patient comfort.
Patients are typically advised to remain isolated during the infectious period, approximately seven days before and after the onset of rash to prevent transmission to others. In community and healthcare settings, strict adherence to respiratory hygiene and infection control measures is recommended.
Medical Interventions
Because rubella is generally mild and self-limiting in otherwise healthy individuals, no antiviral medications are indicated. In cases involving pregnant women, the focus shifts to the prevention and management of congenital rubella syndrome (CRS). When rubella infection occurs during pregnancy, especially in the first trimester, the risk of fetal infection and severe birth defects is significant. In such cases, human normal immunoglobulin (HNIG) may be administered, though evidence for its effectiveness in preventing fetal damage is limited. Close monitoring of pregnancy, including detailed ultrasound and fetal echocardiography, is typically advised.
Management of Complications
Complications such as arthritis typically resolve with supportive treatment, including NSAIDs to reduce joint inflammation and pain. Persistent symptoms may require rheumatologic evaluation.
Congenital rubella syndrome (CRS) requires multidisciplinary care involving pediatricians and specialists to address hearing loss, heart defects, and developmental delays.
Monitoring for rare but serious conditions like encephalitis or thrombocytopenia is necessary. Prompt treatment in these cases can involve corticosteroids or other targeted therapies as guided by specialists.
Prevention and Vaccination
Effective prevention of rubella largely depends on vaccination and maintaining immunity in the population. Understanding vaccine types, schedules, and coverage is critical to controlling outbreaks and protecting vulnerable groups.
Rubella Vaccine Overview
The rubella vaccine is most commonly administered as part of the measles, mumps, and rubella (MMR) vaccine, or in some countries, the measles, mumps, rubella, and varicella (MMRV) vaccine. It contains a live attenuated (weakened) rubella virus strain, most often the RA 27/3 strain, developed to induce immunity without causing the full disease. Once given, the attenuated virus replicates in the body at a much lower intensity than the natural virus, prompting the immune system to produce neutralizing antibodies and memory immune cells. This ensures that, if the vaccinated individual encounters the wild rubella virus in the future, the immune system can respond rapidly to neutralize it before illness develops.
Vaccination is recommended for specific target groups. Children are vaccinated to build immunity early and reduce transmission in schools. Women of childbearing age are a priority because rubella infection during pregnancy can cause congenital rubella syndrome (CRS). Healthcare workers and teachers are also targeted due to their increased risk of exposure. The vaccine is generally safe for most people but is contraindicated in individuals with severe immunosuppression, such as those undergoing chemotherapy or living with advanced HIV, and in pregnant women due to the theoretical risk of harm to the fetus.
Immunization Schedules
Routine childhood immunization remains the foundation of rubella prevention. The first dose of MMR is given at 12–15 months of age, and the second dose is typically administered between 4 and 6 years of age.
The second dose is not primarily a booster but serves to ensure immunity in individuals who did not respond to the first dose—a phenomenon known as primary vaccine failure. Catch-up vaccination is recommended for adolescents and adults without documented immunity, and women planning pregnancy should have their immunity checked, receiving the vaccine at least one month before conception if needed.
Postpartum vaccination is also advised for non-immune mothers to protect future pregnancies. In outbreak settings or countries moving toward elimination, special vaccination campaigns may be implemented, including mass campaigns for specific age groups or supplementary immunization activities (SIAs) in low-coverage areas.
Vaccine Efficacy and Safety
The rubella vaccine is highly effective. A single dose produces protective antibodies in at least 95% of recipients, and two doses raise immunity levels to around 99%, significantly reducing the pool of susceptible individuals. Immunity is generally long-lasting, and routine boosters are not typically necessary.
The vaccine’s safety profile is excellent, with only mild side effects such as fever, rash, or joint aches—more common in adult women. Serious adverse reactions are extremely rare, and decades of global use supported by large-scale safety monitoring have found no credible link to autism or chronic diseases.
Herd Immunity
Herd immunity is a critical factor in controlling rubella. When at least 85–90% of the population is immune, the virus struggles to find susceptible hosts, interrupting sustained transmission. This also provides indirect protection for individuals who cannot be vaccinated, such as young infants and those with severe immune disorders. Countries like the United States, Canada, and many in Europe have eliminated endemic rubella through decades of high vaccination coverage. However, regions with suboptimal coverage continue to experience outbreaks and CRS cases. Maintaining herd immunity is especially important because rubella often spreads silently—many infected people have no symptoms yet can still transmit the virus—placing unvaccinated pregnant women at high risk.
Although vaccination is the most effective prevention strategy, additional measures can complement it. Preconception screening of women ensures immunity before pregnancy.