Rubella

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Rubella

Introduction

Disease History, Characteristics, and Transmission

Scope and Distribution

Treatment and Prevention

Impacts and Issues

BIBLIOGRAPHY

Introduction

The word rubella comes from the Latin word for “little red” and refers to the characteristic rash that accompanies the disease. It was first described in the early nineteenth century, when it was thought to be a type of either scarlet fever or measles. German doctors then decided that rubella was a disease in its own right— which is why it is sometimes called German measles.

People of any age can contract rubella, and there were many epidemics in the first half of the twentieth century. Rubella only poses a real risk to the developing fetus. Infection during the first three months of pregnancy can cause the child to be born with congenital rubella syndrome, which may be accompanied by deafness, mental retardation, and blindness. Vaccination has greatly reduced the rate of rubella in the United States, and it is especially important that women of child-bearing age are protected from the disease.

Disease History, Characteristics, and Transmission

The rubella virus belongs to the togavirus family and is a single-stranded RNA virus—that is, its genetic material is RNA, not DNA. It only naturally infects humans although other animals can be infected in experimental conditions. The incubation period of rubella virus is around 14 days, and infections are most common in late winter and early spring.

Most people with rubella infection have no, or only mild, symptoms. A rash, which is sometimes the only symptom, appears around 14–17 days after exposure to the virus. This rash is fainter than a measles rash and consists of tiny red spots. The rubella rash typically begins on the face and then spreads down the trunk to the rest of the body. Sometimes the rash is preceded by fever and swollen glands, while tiny red spots may appear on the soft palate. Generally the rash clears up in 3–4 days.

Adults are more prone to complications and more severe symptoms of rubella than children. Arthritis in the fingers, wrists, and knees affects 70% of adult females with rubella. Encephalitis (inflammation of the brain) is a rare complication, affecting one in 6,000 rubella cases, and clinical studies have suggested a mortality rate varying between zero and 50%.

Congenital rubella syndrome (CRS) occurs among babies born to a mother who was infected with the virus during early pregnancy. Rubella can affect all the organs of a developing fetus. Deafness is the most common symptom, but cataract and other visual defects, and neurological abnormalities may also occur. The problems may not appear until the child is two to four years old. Other complications arising from CRS include diabetes and autism. Maternal infections occurring after 20 weeks of pregnancy are far less likely to lead to CRS.

Rubella is transmitted by the respiratory route— through coughs and sneezes. It is only moderately contagious. People without symptoms may still be infectious. Those with symptoms are at their most infectious when the rash appears.

WORDS TO KNOW

MEASLES: Measles is an infectious disease caused by a virus of the paramyxovirus group. It infects only man and the infection results in life-long immunity to the disease. It is one of several exanthematous (rash-producing) diseases of childhood, the others being rubella (German measles), chickenpox, and the now rare scarlet fever. The disease is particularly common in both pre-school and young school children.

MMR VACCINE: MMR (measles, mumps, rubella) vaccine is a vaccine that is given to protect someone from measles, mumps, and rubella. The vaccine is made up of viruses that cause the three diseases. The viruses are incapable of causing the diseases but can still stimulate the immune system.

NOTIFIABLE DISEASE: A disease that the law requires must be reported to health officials when diagnosed; also called a reportable disease.

RIBONUCLEIC ACID (RNA): Any of a group of nucleic acids that carry out several important tasks in the synthesis of proteins. Unlike DNA (deoxyribonucleic acid), it has only a single strand. Nucleic acids are complex molecules that contain a cell's genetic information and the instructions for carrying out cellular processes. In eukaryotic cells, the two nucleic acids, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA), work together to direct protein synthesis. Although it is DNA (deoxyribonucleic acid) that contains the instructions for directing the synthesis of specific structural and enzymatic proteins, several types of RNA actually carry out the processes required to produce these proteins. These include messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). Further processing of the various RNAs is carried out by another type of RNA called small nuclear RNA (snRNA). The structure of RNA is very similar to that of DNA, however, instead of the base thymine, RNA co

TOGAVIRUS: Togavirus are a type of virus. Rubella is caused by a type of togavirus.

Scope and Distribution

Rubella has been known since the nineteenth century and was long thought to be a trivial disease. Then, in 1941, the Australian ophthalmologist Norman Gregg reported a worrying trend—78 cases of severe cataracts among newborns, all of which could be traced back to rubella infection among the mothers in early pregnancy. Later, other problems such as heart defects, deafness, and mental retardation were noted in such babies. CRS is now diagnosed in around 85% of babies who have been exposed to rubella in the womb.

Epidemics of rubella were the norm every 7–10 years throughout the first half of the twentieth century and were always followed by an increase in the number of cases of CRS. The last major epidemic in the United States was in 1964 when there were 20,000 resulting cases of CRS and many deaths of babies in the womb.

Rubella and CRS became notifiable diseases in the United States in 1966 and a peak of 57,686 cases was noted in 1969, the year in which a vaccine was first introduced. Since then, cases have fallen to around 0.5 per 100,000 of the population, although there have been outbreaks in California, in 1990, and among the Amish people of Pennsylvania, in 1991. Following these outbreaks, California reported 25 new cases of CRS, Pennsylvania reported 33. The National Congenital Rubella Registry, which is managed by the National Immunization Program, carries out the national surveillance of CRS.

In 2004, the Centers for Disease Control and Prevention declared that rubella was no longer endemic in the United States. Cases that do occur tend to be among Hispanic people who have been born in the Caribbean or in Latin America.

Rubella occurs around the world and it can affect people of any age. However, only around 10% of cases occur in people over 40 years old. In recent years, adults between 15 and 39 have accounted for about half of all cases, so rubella is no longer considered to be a childhood disease.

IN CONTEXT: SCIENTIFIC, POLITICAL, AND ETHICAL ISSUES

With regard to a potential connection between the measles, mumps, and rubella Vaccine (MMR Vaccine) and autism, scientists at the National Immunization Program (NIP) at Centers for Disease Control and Prevention (CDC) state that “the weight of currently available scientific evidence does not support the hypothesis that MMR vaccine causes autism. CDC recognizes there is considerable public interest in this issue, and therefore supports additional research regarding this hypothesis. CDC is committed to maintaining the safest, most effective vaccine supply in history.”

As of May 2007 the CDC further states that, “there is no convincing evidence that vaccines such as MMR cause long term health effects. On the other hand, we do know that people will become ill and some will die from the diseases this vaccine prevents. Measles outbreaks have recently occurred in the UK and Germany following an increase in the number of parents who chose not to have their children vaccinated with the MMR vaccine. Discontinuing a vaccine program based on unproven theories would not be in anyone's best interest. Isolated reports about these vaccines causing longterm health problems may sound alarming at first. However, careful review of the science reveals that these reports are isolated and not confirmed by scientifically sound research. Detailed medical reviews of health effects reported after receipt of vaccines have often proven to be unrelated to vaccines, but rather have been related to other health factors. Because these vaccines are recommended widely to protect the health of the public, research on any serious hypotheses about their safety are important to pursue. Several studies are underway to investigate still unproven theories about vaccinations and severe side effects.”

SOURCE: Centers for Disease Control and Prevention, National Immunization Program

Treatment and Prevention

There is no treatment for rubella infection. The first live vaccines were introduced in 1969 and were replaced by an improved version in 1979. Rubella vaccine is now given in combination with mumps and measles as the MMR vaccine. It is recommended that a child be vaccinated with MMR between the age of 12 and 15 months, and he or she should receive another dose before school entry. Women of childbearing age should be checked for their immunity to rubella, or offered vaccination, if they do not already have evidence of having received the vaccine earlier. This can be done as part of regular gynecologic care, that is, at the family planning clinic, at a sexual health clinic, or in the doctor's office.

The rubella vaccine is very safe and confers lifelong immunity. Any adverse effects from MMR are likely due to the measles component, not the rubella component. However, there is a small theoretical risk that an unborn child could be affected by rubella vaccine, so it is not recommended for pregnant women, or for women who might become pregnant within four weeks of receiving the vaccine.

Impacts and Issues

Despite mass vaccination efforts, there are still an average of five to six cases of CRS per year in the United States. The numbers are tiny, in comparison to the size of the population. Yet each case represents a family tragedy and is costly in terms of health care for the child involved. In the United States, it is estimated that the lifetime health care costs for a person with CRS are more than $200,000. The mothers of most of the babies born with CRS in the United States were themselves born in countries where rubella vaccine was not readily available. Therefore, such vulnerable women should be targeted for rubella vaccination before they become pregnant. In addition, vaccination with MMR ought to be made universally available to reduce the burden of CRS worldwide.