Tuesday, 21 August 2018

Rabies vaccine for travellers

This blog is only addressing the recent changes to rabies vaccine courses and information about boosters FOR TRAVELLERS.  There has also been new information for pre-exposure advice for other groups and for post-exposure treatment for all, but look here for more details on this and on the publications mentioned below.

On 10 July 2018, an updated chapter for rabies (chapter no. 27 in the Green Book) was published.  Then Vaccine update: issue 282, August 2018, rabies special edition was published on 13 August 2018.  Both publications have useful and interesting information about rabies vaccine which should be read.  NaTHNaC also updated their rabies fact sheet on 10 July 2018.

What was the advice regarding rabies pre-exposure prophylaxis and what were the changes for a traveller? 
  • It was stressed that the use of pre-exposure prophylaxis (we refer to as PrEP) reduces the need for rabies immunoglobulin and the number of rabies vaccines given if the traveller is bitten by a potential rabid animal.  Those who receive a primary pre-exposure course (including at least 3 documented doses) and then have a rabies risk exposure would be managed as fully immune for the purposes of post-exposure treatment (we refer to as PEP)
  • In the UK we have always chosen to give 3 doses of rabies vaccine (2.5 IU; one vial) and this continues as the preferred schedule for travellers - given IM on days 0, 7 and 21-28
  • However there is now an accelerated schedule for UK practice given on days 0, 3 and 7 (and a final dose on day 365) which could be used if the traveller does not have time to complete the course on days 0, 7 and 21-28
Additional important information 
  • The Green Book states the JCVI recommends the intramuscular route rather than the intradermal route (except for those with bleeding disorders).  However it also says while IM is preferred, suitably qualified and experienced healthcare professionals may give the vaccine via the intradermal route for pre-exposure prophylaxis.  This will be 'off label' use and is on the prescriber's own responsibility as this route is not covered by the manufacturer's Product Licence.  See page 4 of the Green Book rabies chapter for more information
  • The vaccines we use in the UK are Rabies Vaccine BP and Rabipur® - which contain 2.5IU rabies antigen in a 1ml dose which may be used interchangeably.  Vaccines in other countries may contain different concentrations of rabies antigen
  • Please note the information for pregnant women, breast feeding, those with immunosuppression and HIV infection on page 11 of the Green Book, page 9 of the Vaccine Update 

Booster doses of rabies vaccine
  • Both the Green Book and Vaccine Update say many travellers may not require a booster dose 
  • The emphasis for the need of a booster depends on doing a risk assessment which will include the activities being undertaken, the rabies risk in the country being visited and the ability to access post-exposure medical care
  • The Vaccine Update explains further that the purpose of a booster is to ensure the individual is fully primed for a longer period of time to allow sufficient time to access post-exposure medical care in remote areas
  • If a traveller is given the accelerated schedule on days 0, 3 and 7 then a fourth dose should be given on day 365 - this is NOT a booster dose, but part of the primary course (see page 5 of the Vaccine Update for more detail)
  • A booster dose can then be given at any time from one year after the primary course has been completed although the Vaccine Update says the booster may be most effective if offered 5  years or more after the primary pre-exposure course
  • ONLY ONE BOOSTER is needed in the patient's lifetime when given to a traveller

Personal comment
  • The SmPC for Rabies Vaccine BP does not include the accelerated 0, 3, 7 and 365 day schedule, and the SmPC for this accelerated schedule for Rabipur states to be used in the 18-65 year old age group.  HOWEVER, the NaTHNaC fact sheet (table 1) indicates this new accelerated schedule can be used with either vaccine and in any age group
  • The previous Green Book chapter stated that travellers can be considered for a booster who had a primary course over 10 years ago.  However this has now changed and is based on the thorough risk assessment as mentioned above and can be given from one year.  The impact is the contradiction to the advice we may have given previously, so this new advice will need to be managed carefully when discussing with a traveller.