More good news on ceasing OI prophylaxis

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Preventative medicine for toxoplasma encephalitis may be safely ceased in individuals with sustained CD4 improvements, according to new data from the Swiss Cohort Study published in The Lancet.

The researchers followed 199 HIV-infected individuals, co-infected with Toxoplasma gondii, who had sustained CD4 counts above 200 cells for at least 12 weeks after commencing highly active antiretroviral therapy (HAART). None of the group had previously had toxoplasma encephalitis but all had been taking primary prophylaxis against T gondii. Median duration of prophylaxis was 26 months.

No cases of toxoplasma encephalitis occurred in the group after a median follow-up time of 1.4 years (range 0.1-2.4 years). Statistical analysis indicated that the incidence of toxoplasmosis in this study was below the frequency of an historical comparison group. Only four individuals in the study resumed prophylaxis when their CD4 levels fell below 200.



A disease due to infection with the protozoa Toxoplasma gondii, usually transmitted through consuming contaminated food and drink or undercooked meat.


opportunistic infection (OI)

An infection that occurs more frequently or is more severe in people with weakened immune systems, such as people with low CD4 counts, than in people with healthy immune systems. Opportunistic infections common in people with advanced HIV disease include Pneumocystis jiroveci pneumonia; Kaposi sarcoma; cryptosporidiosis; histoplasmosis; other parasitic, viral, and fungal infections; and some types of cancer. 

immune system

The body's mechanisms for fighting infections and eradicating dysfunctional cells.

The authors concluded that stopping primary prophylaxis for toxoplasma encephalitis is safe among individuals with sustained immune recovery due to HAART. The findings suggest there may be a change to current guidelines issued by the US Centers for Disease Control which state that there is insufficient evidence to recommend cessation of prophylaxis against T gondii.

The findings add to a growing body of research which demonstrates that immune restoration due to HAART is effective in preventing a range of opportunistic infections. You can read more about this subject here on in Prophylaxis and immune recovery in Restoring the immune system.


Furrer H et al. Stopping primary prophylaxis in HIV-1-infected patients at high risk of toxoplasma encephalitis. Lancet 355:2217-2218, 2000.