Health professionals are reminded that, to minimise the risk of fever and febrile convulsion, measles, mumps, rubella, varicella vaccine should not be administered as the first dose of measles-containing vaccine to children younger than four years.
Measles, mumps, rubella, varicella ( MMRV ) vaccine is a combination live virus vaccine for immunisation against these four common childhood illnesses.
While MMRV vaccine is approved for use in children from nine months of age, on 1 July 2013 it was added to the National Immunisation Program ( NIP ) schedule to be given at 18 months after an initial dose of measles, mumps, rubella ( MMR ) vaccine at 12 months of age.
Like most vaccines, MMRV vaccine can cause some mild adverse events. In rare cases, fever after vaccination can lead to febrile convulsions in young children.
MMRV vaccine is only recommended for use as a second dose of measles-containing vaccine. This is because MMRV vaccine administered as a first dose in children aged 9-30 months is associated with an increased rate of fever and febrile convulsions, compared to separate MMR and varicella vaccination.
As described in the post-marketing data section of the Product Information ( PI ), the attributable risk of febrile convulsions 5-12 days following MMRV vaccination as a first dose of measles-containing vaccine is 3.64/10 000 ( 95% CI: -6.11;8.30 ). This equates to one additional case of febrile convulsion per 2747 young children, when compared to MMR or concomitant MMR and varicella vaccination.
When used as the second measles-containing vaccination, there is no indication of an increased risk.
The overall risk of fever and subsequent febrile convulsion in children is greatly reduced by following the NIP schedule of the initial dose of MMR vaccine at 12 months and the second vaccine dose, as MMRV, at 18 months.
Dosage instructions in the PI recommend an interval of six weeks to three months between the first and second vaccine doses. As with other live virus vaccines, under no circumstances should the interval be less than four weeks.
The TGA ( Therapeutic Goods Administration ) continues to receive adverse event reports that suggest MMRV vaccine has been administered as the first dose of measles-containing vaccine in children aged 12 months or younger. In the 12 months to 1 May 2014, the TGA has received seven such reports. There were also two reports of MMRV vaccine being given at the same time as other vaccines that contain either MMR or varicella. ( Xagena )
Source: TGA - Medicines Safety Update, Volume 5, Number 4, 2014