He collaborated with teams at the forefront of AIDS research, publishing several papers and advocating for strategies to translate knowledge gained from clinical studies to the practical treatment of patients afflicted by chronic viral diseases.

[9] Redfield also authored the foreword to the 1990 book co-written by ASAP leader W. Shepard Smith, "Christians in the Age of AIDS", which discouraged the distribution of sterile needles to drug users as well as condom use, calling them "false prophets".

[11] In 1992, the Defense Department investigated Redfield after he was accused of misrepresenting the effects of an experimental HIV vaccine, the study of which he had overseen.

[12][13][14] On the basis of this data, in 1992, the U.S. Senate gave a $20 million appropriation for a private company, MicroGeneSys, to develop a therapeutic HIV vaccine based on the protein gp160, which went into clinical trials.

[13][16] Craig Hendrix, a US Air Force scientist (now at Johns Hopkins) said that Redfield committed scientific misconduct by misusing data in studies of the vaccine.

[citation needed] Redfield is quoted in Big Shot: Passion, Politics, and the Struggle for an AIDS Vaccine, the comprehensive book on the controversy, as saying of his accusers, "I am disappointed in the institutions for not holding the individuals accountable for what I consider conduct unbecoming of an officer.

[19] Redfield's multi-site study was a collaboration between the Department of Defense and the National Institutes of Health,[19] The work did not, however, result in an effective vaccine.

[12] The 1993 investigation said that Redfield had an "inappropriate" close relationship with the non-governmental group "Americans for a Sound AIDS/HIV Policy" (ASAP), which promoted the gp160 vaccine.

The group was founded by evangelical Christians who worked to contain the HIV/AIDS outbreak by advocating for abstinence before marriage, rather than passing out condoms — a view Redfield says he's since changed.

[18][20] In 1996, Redfield, his HIV research colleague Robert Gallo and viral epidemiologist William Blattner co-founded the Institute of Human Virology at the University of Maryland School of Medicine.

In the early years of investigations into the AIDS pandemic in the 1980s, Redfield led research that demonstrated that the HIV retrovirus could be heterosexually transmitted.

[27][28] Redfield served as a member of the President's Advisory Council on HIV/AIDS from 2005 to 2009,[citation needed] and was appointed as chair of the International Subcommittee from 2006 to 2009.

[33][34][35][36] Redfield was criticized for maintaining close ties with homophobic activists,[9] although he has publicly supported the use of condoms and denied ever promoting abstinence-only interventions.

[38] On January 8, 2020, Redfield was advised by the head of China's Center for Disease Control and Prevention that SARS-CoV-2 (the virus that causes COVID-19) was probably contagious among humans.

[45] Later investigations by the Food and Drug Administration and the Department of Health and Human Services found that the CDC had violated its own protocols in developing the faulty test.

Redfield could not name a specific individual and looked to Anthony Fauci, director of infectious disease at the NIH, who said, "The system is not geared to what we need right now... that is a failing.

Redfield told a Senate panel that a limited supply of a COVID-19 vaccine might be available in November or December, but that the general public would not be inoculated until the summer or fall of 2021.

[57][58] In September 2020, Redfield sought to extend a no-sail order on passenger cruise ships into 2021 to prevent the spread of COVID-19, but he was overruled by Vice President Mike Pence.

[63] In June 2021, Redfield told Vanity Fair that he received death threats from people who disagreed with his statements about the origin of COVID-19.

He stated that he was targeted by fellow scientists and ostracized for offering this alternative hypothesis, and highlighted the rising tensions surrounding the virus's origins.