What Is Rubella?

Introduction

Rubella, also called German measles, is a mild viral infection that typically resolves without intervention or treatment. Rubella is characterised by a rash, low-grade fever, and swelling of the lymph nodes. It typically occurs in children and causes mild illness. However, it can also cause a more severe illness in non-immune adults.

Rubella can be spread through droplets that are coughed or sneezed into the air by an infected person. The average time for the symptoms to develop after exposure to the virus is about 2 to 3 weeks. Although the illness is mild, the virus can cause congenital rubella syndrome in pregnant women, which can cause severe birth defects.^1,2,3

Who is affected by rubella?

Rubella occurs worldwide with higher frequency during late winter and early spring. It most commonly infects children between 5 to 9 years of age. Rubella affects both sexes equally in children, but in adults, it affects individuals assigned female at birth more. Since the introduction of a rubella vaccine in the 1960s, incidence rates have decreased by about 99%. However, there are still some cases of congenital rubella, which are mainly seen in unvaccinated adults.^1,2

Those at a higher risk of contracting rubella are:¹

• Unvaccinated or incompletely vaccinated individuals
• Those travelling to areas where rubella is endemic 
• Immunodeficient individuals (who have impaired immune systems)
• Those with family members infected with rubella

The expected rate of rubella incidence in countries where rubella is endemic (often found) is 1.30/100000 in the population.¹

How does rubella spread?

Rubella virus is transmitted through person-to-person contact or via droplets. Once it is inside the body, the virus invades the cells in the nose through a mechanism known as receptor-mediated endocytosis, in which cells that usually absorb hormones and proteins accidentally absorb the virus as well. Within these cells, the virus replicates until it can spread to the lymphoid tissues and the upper respiratory tract and, eventually, its target organs (such as the spleen and lymph nodes). This all occurs within 5-7 days after the virus enters the body.^1,2

In congenital rubella syndromes (CRS), in which rubella is passed from mother to child, viral transmission occurs via the placenta. Interestingly, the risk of transmission to the foetus is inversely proportional to the gestational age at maternal infection. For example, if the parent gets infected with rubella before the foetus is 10 weeks old, the risk of foetal defects is higher than if the foetus were 20 weeks old.  

The risk of these foetal defects is affected by a few factors, including death of infected cells, damage of chorionic villi (hair-like cells that maximise blood flow to the foetus), blood supply to the foetus’s developing organs, and rates of foetal mitosis (cell division, an essential process in the human body).¹

Symptoms

Rubella can be asymptomatic (cause no symptoms) in up to 50% of patients.^1,3

The time between infection and symptoms appearing ranges from 14 to 21 days. These symptoms include:

• Low-grade fever
• Lymphadenopathy (inflamed lymph nodes in the  back of the neck, back of the ear, and back of the head)
• Sore throat
• Headaches
• Malaise (general discomfort)
• Anorexia
• Rash (pinpoint pink bumps or flat lesions begin on the face and rapidly spread to the torso, arms and legs) that lasts about 3 days)

Potential consequences of rubella infection during the first eight weeks of embryo development include: 

• Deafness
• Congenital heart defects
• Cataracts (cloudy vision)

Moreover, CRS has been associated with:

• Hemolytic anaemia
• Low birth weight
• Meningoencephalitis (inflammation of the brain tissue)
• Hepatosplenomegaly (enlargement of liver and spleen)
• Thrombocytopenia purpura (a disorder which causes bleeding issues)
• Cardiac abnormalities
• Microcephaly (small head)
• Psychomotor retardation (reduction of thought and physical movement)
• Ophthalmopathy (thyroid eye disease)

Complications

In adults, the most common complications are polyarthritis (arthritis in five or more joints) and polyarthralgia (pain in multiple joints).

Other rare complications are:

• Hemolytic anaemia
• Myocarditis
• Pericarditis
• Thrombocytopenia
• Retinopathy
• Hepatitis
• Uveitis
• Orchitis
• Encephalitis

During pregnancy, complications of rubella include premature labour, miscarriage, intrauterine growth retardation, and congenital rubella syndrome. The development of such complications is highly linked to the gestational age within the first 12 weeks.¹

Diagnosis

It can be difficult to diagnose rubella, as it is associated with several mild and non-specific symptoms. Along with a review of the patient’s medical history and a medical examination, a diagnosis by a physician is confirmed using blood tests.^1,3

The most commonly used diagnostic test is enzyme immunoassay, which detects rubella-specific antibodies. In pregnant people who are suspected to have been exposed to rubella, a sample of blood should be taken and tested immediately. If the results are positive, the mother is immune (and therefore, their child is not at risk of CRS). However, if it is negative, another test should be conducted in 3 weeks to rule out asymptomatic primary rubella infection.

Congenital rubella syndrome (CRS) can be diagnosed by running tests on foetal blood or amniotic fluid or by taking a biopsy of the chorionic villi cells. Specific antibodies used to fight rubella and rubella virus molecules can be detected in foetal blood. Rubella molecules can also be observed in the amniotic fluid or chorionic villus. 

In a newborn, CRS can be detected using blood tests or RT-PCR (reverse transcription polymerase chain reaction) to detect viral genetic material in samples taken from the nose, oral fluid, or urine. 

Treatment and management

Treatment of rubella is mainly supportive, as it is a self-limiting illness (meaning that it goes away without treatment). There is no specific treatment for rubella, but its symptoms can be managed.^1,3 For example, paracetamol and non-steroidal anti-inflammatory drugs are used for fever and other complications that might follow like arthralgia (joint pain) or arthritis. 

In congenital rubella syndrome, the management is linked to the gestation age at the onset of infection. If the infection occurs before 18 weeks, the risk is high for foetal defects or even foetal loss. Doctors may discuss pregnancy termination. However, if infection occurs after 18 weeks of gestation, the pregnancy can proceed with close monitoring and follow-up ultrasounds. 

Children with congenital rubella syndrome can have symptom-specific treatment and organ-specific treatment. The latter can involve several medical interventions in terms of ophthalmologic (eyes), audiological, paediatric, neurodevelopmental, and cardiac assessments. Delayed observed clinical symptoms require long-term follow-up. 

Differential diagnoses

Other infections that cause similar rashes to rubella include human herpesvirus 6 and 7, cytomegalovirus (CMV), measles, mononucleosis, scarlet fever, enteroviruses, arboviruses (viruses spread by a type of insect), and mycoplasma infection (an infection caused by a mycoplasma germ which can affect various parts of the body). Similar rashes can also have non-infectious causes, such as drug rash, contact dermatitis (a type of eczema), and Kawasaki disease. Some of these issues require intervention to prevent severe side effects, thus, it is essential for a healthcare professional to distinguish rubella from other infections quickly.¹

Prognosis

Rubella is a self-limiting, mild illness. As such, it has an excellent prognosis and often resolves within a week. However, the prognosis of congenital rubella syndrome depends on the gestational age at the time of infection, infection severity, and complications.¹

Vaccination

The rubella vaccine prevents rubella. The vaccine is available in two forms, one form as part of the combined measles, mumps, and rubella vaccine (MMR), and the other form is MMR combined with varicella (MMRV). 

The MMR and MMRV are both live attenuated vaccines, meaning they contain a weakened version of the living virus that cannot cause serious illness in individuals with healthy immunity.

Both vaccines are injected beneath the skin (subcutaneously) in 2 doses: 

• First dose at 12 to 15 months 
• Second dose at 4 to 6 years

Pregnant people with no evidence of rubella immunity should receive the MMR vaccination as soon as possible after giving birth and before discharge from the healthcare facility.⁴

These vaccines are incredibly effective in controlling the spread of rubella, with the World Health Organisation reporting that cases have dropped by 97% between 2000 and 2022 across 78 countries.⁵

Summary

Rubella is a viral infection that causes mild illness in children and a more severe illness in adults. It is self-limiting, meaning that it goes away without treatment. However, it can cause more severe illness in patients with immunodeficiency, particularly pregnant women. 

Rubella can be transmitted from person to person via air droplets coughed or sneezed by an infected person. The onset of symptoms is about 2 to 3 weeks. In congenital rubella syndrome (CRS), the rubella virus is transmitted from the placenta to the foetus.  

The most common symptoms of rubella are a rash, adenopathy (swelling of glands like lymph nodes), and a slight fever. However, more severe complications are associated with CRS. 

Rubella can be hard to diagnose, but it is most often confirmed by blood testing and a throat swab culture.

Rubella is prevented through the MMR vaccine during childhood. The first dose is given at 12 to 5 months old, and the second dose is given at 4 to 6 years of age.

FAQs

When should I call my healthcare provider?

Rubella is a self-limiting infection, meaning it will most likely clear within a week. However, you should inform your healthcare provider in these cases:

• Your symptoms are getting worse, or you developed new symptoms
• You are pregnant or planning to be, and you're not sure if you have evidence of immunity.
• You have problems with your vision, earache, severe headache, and stiff neck. 

Can rubella be prevented?

Individuals who have had measles, mumps, and rubella vaccine (MMR) in childhood are protected against the virus and immune for life.

About the rubella virus

The rubella virus is a single-stranded RNA virus. The rubella virus encodes two non-structural proteins (p90 and p150) and three structural proteins; the capsid protein (CP) and the glycoproteins (E1 and E2). The E1 protein is the sole protein responsible for host cells invading through a mechanism known as receptor-mediated endocytosis which induces immune response via a process known as hemagglutination-neutralising epitopes. 

The virus can be destroyed by temperatures above 56°C, pH levels lower than 6.8 or larger than 8.1, and ultraviolet light.¹

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Amani Doklaija

Master of Science, pharmaceutical science route, clinical biochemistry, and toxicology specialism – UEL (University of East London), London, UK

Amani Doklaija holds a Master of Science in Pharmaceutical Science with a specialization in Clinical Biochemistry and Toxicology from the University of East London (UEL), London, UK. She is a registered overseas community and hospital pharmacist with a strong passion for pharmaceutical and biomolecular research and expertise in medical writing.

Amani possesses a solid background in lab-based procedures and is highly motivated and vigilant in completing complex tasks on time. She is skilled in consultative and advisory strategies and has gained a basic foundation in forensic science and toxicology through her master’s studies and online sessions.

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