Nearly 80% of patients with IBD are treated with corticoid therapy, 40% with thiopurine and 20% with anti-tumor necrosis factor. These molecules act by decreasing intestinal immunity, but they also diminish the immune response of the entire organism. This state of immunodepression, necessary for controlling the disease, carries with it an increased risk of infection, possibly severe, thereby affecting vital prognosis. Hence the importance of vaccination.
Two groups of vaccines exist : attenuated vaccines (including viruses or live bacteria that have lost their pathogenicity) and inactivated or recombinant vaccines comprised of dead whole microorganisms or some of their purified components.
While attenuated vaccines are contra-indicated in patients treated with immunosuppressors (due to risk of vaccine-induced disease), inactivated or recombinant vaccines can be used without risk.
Thus, it is strongly recommended that all patients with IBD not only undergo a vaccine check-up, but also that they be vaccinated against particularly virulent diseases affecting immunodepressed persons. This should be done prior to starting immunosuppressive treatment, ideally during the general check-up at the time of diagnosis :
- For the usual vaccines against tetanus, diphtheria, polio and whooping cough, it is advisable to evaluate immune status and revaccinate if necessary;
- Five other vaccines are currently strongly recommended, since the benefit/risk ratio is very high; these include vaccines against chicken pox, human papillomavirus, influenza, pneumococcus and hepatitis B in patients who are seronegative for HBV.
- Concerning vaccines necessary for travel, specialists should be consulted in each case.
By Jean-François Rahier
Références
European evidence-based Consensus on the prevention, diagnosis and management of opportunistic infections in inflammatory bowel disease ; Journal of Crohn‘s and Colitis, 2009
