Causative Agent
Rubella virus
Incubation Period
Infectious Period
Few days before until seven days after onset of rash. Infants with congenital rubella syndrome may shed the virus from their body secretions for 1 year or more after birth.
Transmission
Respiratory droplets and direct contact with nasopharyngeal secretions.
Epidemiology
Rubella immunisation was introduced in Nov 1976 for female primary school leavers at 11+ years of age. However as rubella outbreaks continued to occur in susceptible populations especially national servicemen (NS men), the vaccination was extended to cover male primary school leavers in 1982. NS men were also routinely vaccinated to eliminate rubella in army camps. The programme was further expanded to include children 1-2 years of age using the trivalent measles, mumps, rubella (MMR) vaccine in Jan 1990. The 2nd dose of MMR was introduced in 1997 for secondary and junior college students in a catch-up measles vaccination programme and to all primary school leavers in 1998. Since 2008, the 2nd dose of MMR vaccine is now given at 6-7 years of age (primary 1) under the revised National Childhood Immunisation Programme.
The rubella incidence peaked in 1996 with 487 notifications. With the catch-up measles vaccination program, the number of rubella cases has gradually declined from 10.9 cases per 100,000 population in 1999 to 3.6 per 100,000 in 2009. The incidence of congenital rubella is about 0-2 cases per year since 1995.
In a serosurveillance study of rubella conducted in 1998, it was found that the overall immunity of the population to rubella was 80.2% with the lowest immunity in the 10-14 year age group (65.5%). Another survey in 2004 showed that 15.8% of women aged 18 to 44 years were non-immune to rubella (a relatively high level compared to women of reproductive age in other developed countries).
It is important to ensure that at least 95% of the children are immunised at 1-2 years of age. Congenital rubella can only be completely eliminated if every woman in the 15-44 year age group is immunised against the disease. Women should be advised to be vaccinated before they are married and prior to conception.