Opportunistic infections can occur in up to 40% of people with HIV infection and a CD4 count less than 250/mm3, although the risks are much lower with use of highly active antiretroviral treatment.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of prophylaxis for Pneumocystis jirovecii pneumonia (PCP) and toxoplasmosis? What are the effects of antituberculosis prophylaxis in people with HIV infection? What are the effects of prophylaxis for disseminated Mycobacterium avium complex (MAC) disease for people with, and without, previous MAC disease? What are the effects of prophylaxis for cytomegalovirus (CMV), herpes simplex virus (HSV), and varicella zoster virus (VZV)? What are the effects of prophylaxis for invasive fungal disease in people with, and without, previous fungal disease? What are the effects of discontinuing prophylaxis against opportunistic pathogens in people on highly active antiretroviral treatment (HAART)? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 43 systematic reviews, RCTs, or observational studies that met our inclusion criteria.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: aciclovir; antituberculosis prophylaxis; atovaquone; azithromycin (alone or plus rifabutin); clarithromycin (alone, or plus rifabutin and ethambutol); discontinuing prophylaxis for CMV, MAC, and PCP; ethambutol added to clarithromycin; famciclovir; fluconazole; isoniazid; itraconazole; oral ganciclovir; rifabutin (alone or plus macrolides); trimethoprim–sulfamethoxazole; and valaciclovir.
Opportunistic infections can occur in up to 40% of people with HIV infection and a CD4 count less than 250/mm3, although the risks are much lower with use of highly active antiretroviral treatment (HAART).
HAART has reduced the rate of Pneumocystis jirovecii pneumonia (PCP), toxoplasmosis, and other opportunistic infections, so the absolute benefits of prophylactic regimens for opportunistic infections are probably smaller in people with HIV who are also taking HAART, and even smaller for those whose HIV is suppressed.
Primary prophylaxis with trimethoprim–sulfamethoxazole may reduce the risk of PCP, and has been found to be more effective than pentamidine or dapsone.
Atovaquone may prevent PCP in people who cannot tolerate trimethoprim−sulfamethoxazole.We don't know whether these drugs prevent toxoplasmosis as we found few RCTs, but there is consensus that standard trimethoprim–sulfamethoxazole prophylaxis or dapsone should offer adequate coverage for toxoplasmosis.
Tuberculosis can be prevented by standard primary prophylaxis in people who are tuberculin skin test positive.
Short-term combination treatment has similar efficacy to long-term isoniazid monotherapy, but is associated with a greater risk of adverse effects.
Azithromycin or clarithromycin reduce the risk of disseminated Mycobacterium avium complex (MAC) disease as primary prophylaxis for people without prior MAC disease. Adding rifabutin may also be beneficial in this population, but is also associated with an increased risk of adverse effects.
There is consensus that secondary prophylaxis with clarithromycin plus ethambutol decreases the risk of relapse in people with previous MAC disease. It remains unclear whether adding rifabutin to the dual drug regimen confers additional benefit as secondary prophylaxis, and the three-drug combination increases adverse effects.
Aciclovir as secondary prophylaxis reduces the risk of herpes simplex virus (HSV) and varicella zoster virus infection (VZV) and all-cause mortality.
Valaciclovir may reduce the risk of recurrent HSV infection, but it may be associated with serious adverse effects.There is consensus that famciclovir is effective as secondary prophylaxis against HSV or VZV and that ganciclovir is effective as secondary prophylaxis against CMV, HSV, or VZV.
Fluconazole and itraconazole as primary prophylaxis may reduce the risk of invasive fungal infections, but azoles have been associated with potentially serious interactions with other drugs.
As secondary prophylaxis, itraconazole seems effective in reducing relapse of Penicillium marneffei, but seems less effective than fluconazole at reducing recurrence of cryptococcal meningitis.
In people who have responded to HAART and have a CD4 cell count greater than 100/mm3 to 200/mm3 (depending on the condition), discontinuation of primary or secondary prophylactic treatment for PCP, toxoplasmosis, MAC, herpes virus, or invasive fungal disease infection seems safe.