Rubella is an acute, contagious viral infection. While rubella virus infection usually causes a mild fever and rash in children and adults, infection during pregnancy, especially during the first trimester, can result in miscarriage, fetal death, stillbirth, or infants with congenital malformations, known as congenital rubella syndrome (CRS).
The rubella virus is transmitted by airborne droplets when infected people sneeze or cough. Humans are the only known host.
Symptoms
In children, the disease is usually mild, with symptoms including a rash, low fever (<39°C), nausea and mild conjunctivitis. The rash, which occurs in 50–80% of cases, usually starts on the face and neck before progressing down the body, and lasts 1–3 days. Swollen lymph glands behind the ears and in the neck are the most characteristic clinical feature. Infected adults, more commonly women, may develop arthritis and painful joints that usually last from 3–10 days.
Once a person is infected, the virus spreads throughout the body in about 5-7 days. Symptoms usually appear 2 to 3 weeks after exposure. The most infectious period is usually 1–5 days after the appearance of the rash.
When a woman is infected with the rubella virus early in pregnancy, she has a 90% chance of passing the virus on to her fetus. This can cause the death of the fetus, or it may cause CRS. Infants with CRS may excrete the virus for a year or more.
Congenital rubella syndrome
Children with CRS can suffer hearing impairments, eye and heart defects and other lifelong disabilities, including autism, diabetes mellitus and thyroid dysfunction – many of which require costly therapy, surgeries and other expensive care.
The highest risk of CRS is in countries where women of childbearing age do not have immunity to the disease (either through vaccination or from having had rubella). Before the introduction of the vaccine, up to 4 babies in every 1000 live births were born with CRS.
Vaccination
The rubella vaccine is a live attenuated strain, and a single dose gives more than 95% long-lasting immunity, which is similar to that induced by natural infection.
Rubella vaccines are available either in monovalent formulation (a vaccine directed at only one pathogen) or more commonly in combinations with other vaccines such as with vaccines against measles (MR), measles and mumps (MMR), or measles, mumps and varicella (MMRV).
Adverse reactions following vaccination are generally mild. They may include pain and redness at the injection site, low-grade fever, rash and muscle aches. Mass immunization campaigns in the Region of the Americas involving more than 250 million adolescents and adults did not identify any serious adverse reactions associated with the vaccine.
WHO response
WHO recommends that all countries that have not yet introduced rubella vaccine should consider doing so using existing, well-established measles immunization programmes. To-date, four WHO regions have established goals to eliminate this preventable cause of birth defects. In 2015, the WHO Region of the Americas became the first in the world to be declared free of endemic transmission of rubella.
The number of countries using rubella vaccines in their national programme continues to steadily increase. As of December 2018, 168 out of 194 countries had introduced rubella vaccines and global coverage was estimated at 69%. Reported rubella cases declined 97%, from 670 894 cases in 102 countries in 2000 to 14 621 cases in 151 countries in 2018. CRS rates are highest in the WHO African and South-East Asian regions where vaccination coverage is lowest.
In April 2012, the Measles Initiative – now known as the Measles & Rubella Initiative – launched a Global Measles and Rubella Strategic Plan which covers the period 2012-2020. The Plan includes a series of global goals for 2020.
By the end of 2020
- Achieve measles and rubella elimination in at least 5 WHO regions.
Based on the 2018 Global Vaccine Action Plan (GVAP) Assessment Report by the WHO Strategic Advisory Group of Experts (SAGE) on Immunization, rubella control is lagging, with 26 countries still do introduce the vaccine, while two regions (African and Eastern Mediterranean) have not yet set rubella elimination or control targets.
SAGE recommends that rubella vaccination should be incorporated into immunization programmes, as quickly as possible, to ensure additional gains in controlling rubella can be made. As one of the founding members of the Measles & Rubella Initiative, WHO provides technical support to governments and communities to improve routine immunization programmes and hold targeted vaccination campaigns. In addition, the WHO Global Measles and Rubella Laboratory Network supports the diagnosis of rubella and CRS cases and tracking of the spread of rubella viruses.