(February 15, 2013) A new study published in the journal Clinical Infectious Diseases actually claims taking antidepressants will increase vaccine effectiveness.

The two-year study compared immune responses in 40 elderly participants with major depressive disorder to 52 control subjects in regard to Merck’s Zostavax, the herpes zoster (shingles) vaccine. According to an Infectious Diseases Society of America press release:

"Depressed patients not being treated with antidepressants (selective serotonin reuptake inhibitors) had lower cell-mediated immunity to the varicella-zoster virus—and were less able to respond to the shingles vaccine—compared with patients who were not depressed or who were depressed but were receiving treatment with antidepressants, the researchers found."

The implications here are much more frightening, as the press release continued:

"The possible connection, however, is potentially significant: If antidepressants increase the efficacy of the shingles vaccine in those who are depressed, such treatment may have a similar effect on the immune response of depressed patients to other important vaccines, such those against influenza.