Are immunosuppressive medications associated with decreased responses to routine immunizations? A systematic review

Background: Long-term immunosuppressive medications are being used more commonly for a variety of medical conditions, including immune-mediated diseases and organ transplantation. While these medications are often necessary, they are associated with an increased risk of serious infections. Vaccination may be a way to prevent a variety of infections but vaccine responses among patients receiving immunosuppressive therapies have been variable.

Purpose: To systematically review the literature describing immune responses among patients on immunosuppressive therapies to vaccinations including influenza, pneumococcal, meningococcal, hepatitis A and B, tetanus toxoid, pertussis, varicella, and zoster.

Data sources: English language citations in the MEDLINE and EMBASE databases from 1985 to 2010.

Study selection: Two reviewers independently screened titles and abstracts to identify prospective, controlled studies reporting pre- and post-vaccination titers of recommended vaccines in patients receiving long-term immunosuppressive therapies for full-text review.

Data extraction: Three reviewers independently assessed study characteristics including treatment regimens and pre- and post-vaccination titers.

Data synthesis: Of the 972 identified titles, fifteen met inclusion criteria. Ten studies assessed the effects of immunosuppressive medications on responses to influenza vaccine, four studies investigated responses following pneumococcal vaccination, and one study assessed both influenza and pneumococcal vaccination. Five of the studies that evaluated influenza vaccination showed partially diminished responses among individuals receiving immunosuppressive therapies, while one of the pneumococcal vaccine studies showed significantly decreased responses following vaccination. Patients treated with more than one immunosuppressive medication were the least likely to respond to vaccination.

Limitations: The heterogeneity of reported outcomes limits generalizeability.

Conclusions: Immunosuppressive therapy, particularly combination regimens, may blunt response to influenza and pneumococcal vaccinations. To ensure the best chance of response, immunizations should be administered prior to initiation of immunosuppressive medications whenever possible.