Last year Selenium supplements were touted as an aid to combat HIV.

<http://www.aidsmap.com/en/news/2571C611-2069-48F8-ACAB-A21FE0BD28E0.asp>:

----- Begin Quote -----

Daily supplementation with 200ug of selenium daily stabilised viral
load and modestly increased CD4 cell counts in both untreated and
viremic patients on antiretroviral therapy in a nine-month randomised
trial, researchers from the University of Miami report...

[...]

Selenium is a mineral essential for human health. Deficiencies can
lead to immune dysfunction and cardiomyopathy, and are common in
resource-limited settings and in countries with low selenium levels in
soil.

Selenium deficiency has been noted in HIV disease and predicts an
increased risk of death. However, incubation of HIV-infected monocytes
in the test tube with selenium results in the suppression of HIV
replication.

----- End Quote -----

Researchers have recently concluded that taking extra supplements,
such as vitamin A, vitamin C, vitamin E and selenium, may shorten
lifespan.

<http://news.bbc.co.uk/1/hi/health/7349980.stm>:

----- Begin Quote -----

Research has suggested vitamin supplements do not extend life and
could even lead to a premature death.

[...]

The research involved selecting various studies from 817 on
beta-carotene, vitamin A, vitamin C, vitamin E, and selenium which the
team felt were the most likely to fairly reflect the benefits of the
supplements.

----- End Quote -----

The basis of the research has been questioned.  The article also
contains this: "[A] nutritionist who has formulated supplements
described the review as a "stitch-up" and only reviewed studies which
examined the effect they had on reducing mortality, rather than other
advantages."