Rubella

Rubella a mild illness caused by infection with the rubella virus, which is an RNA togavirus and the only member of the genus Rubivirus. Humans are the only natural host. Spread of the virus is by droplets from the respiratory tract. (1)

Individuals with rubella are most infectious during the eruption of the rash but the infectious period may vary from 7 days before to 4 days after the onset of the rash (1).

The true importance of rubella is the teratogenicity of the virus during the first trimester of pregnancy, resulting in foetal loss or congenital rubella syndrome (CRS). The risk of intrauterine transmission causing foetal damage varies with the gestational stage: (2,3)

• if <11 weeks – foetal damage in up to 90% of surviving infants, multiple defects can be seen
• 11-16 weeks – the risk declines to about 20%
• 16-20 weeks – foetal damage is rare, but there is a minimal risk of deafness
• >20 weeks - no increased risk

It is for this reason that there is an extensive immunisation program in the UK.

It is a notifiable disease in UK (4).

Click here for an example image of rubella rash

References:

1. Rubella. In: Hamborsky J, Kroger A, Wolfe C, eds. CDC The Pink Book: Epidemiology and prevention of vaccine-preventable diseases. Aug 2021 [internet publication].
2. Centers for Disease Control and Prevention. Rubella (German measles, three-day measles). Dec 2020 [internet publication]
3. Mawson AR, Croft AM. Rubella Virus Infection, the Congenital Rubella Syndrome, and the Link to Autism. Int J Environ Res Public Health. 2019 Sep 22;16(19):3543
4. UK Health Security Agency. Rubella (German measles): guidance, data and analysis. Published 1 April 2013. Last updated 22 November 2022