Thursday, 16 June 2011

Yellow Fever Vaccination and Increased Relapse Rate in Travelers With MS

Farez and Correale. Arch Neurol. 2011 Jun 13. [Epub ahead of print]

A small study that investigated the effect of yellow fever immunization on the subsequent risk of MS relapse in 7 PwMS. Result: The annual exacerbation rate during risk periods following immunization was 8.57, while the relapse rate outside the risk period was only 0.67 (rate ratio = 12.778; P < .001). Three and nine months after immunization, the PwMS showed a significant increase in MRI activity compared with 12 months prior to vaccination. Conclusions: For patients with MS traveling to endemic yellow fever areas, vaccination should be recommended on the basis of carefully weighing the risk of exacerbation against the likelihood of exposure to the yellow fever virus.

"This is a small study but confirms my predictions of live vaccinations to PwMS. It is well established that infections are a potent trigger of MS relapses. It is therefore not surprising that a live vaccine does the same. The good news is that the development of  an inactivated yellow fever vaccine is well advanced. Another issue for PwMS to consider is the risk of exotic infections whilst taking immunosuppressive agents."

4 comments:

  1. So are flu jabs a no-no?

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  2. Flu jabs are fine; the current vaccine is not a live virus, but an inactivated virus. My caution only applies to live viral vaccines. Even then they are not contra-indicated, PwMS must be aware that they can trigger disease activity and there for the risk of the vaccine has to be balanced against risk of triggering disease activity (relapses).

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  3. Hi!
    I would like to confirm if you still think there is no problem with immunizations, as long as it isn't with a live vaccine.
    I am currently not taking any DMTs (took for a long period but now i have SPMS) and i'm going to sri lanka so many people told me i should take a lot of vaccines.
    What do you think?
    Thank you very much,
    P

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    Replies
    1. Re: "..I would like to confirm if you still think there is no problem with immunizations."

      We simply don't have the data on the safety of live vaccines in MS. We do know that infections trigger relapses and live vaccines work by causing an attenuated infection. I particularly against yellow fever vaccines as acute demyelinating encephalomyelitis or ADEM is a well described and not that uncommon complication of yellow fever vaccines. Therefore I advise patients to try and avoid this vaccine. However, there are no hard rules and it is always a personal risk:benefit assessment that needs to be taken.

      Please note that yellow fever is transmitted by anopheles mosquitoes that tend to be nocturnal (dusk and dawn biters) so there are other ways to avoid yellow fever.

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