McCullough is a founder and (as of 2021) president of the now defunct[13] Cardio Renal Society of America[9][14] and co-editor-in-chief of Cardiorenal Medicine, the society's journal,[citation needed] and also editor of Reviews in Cardiovascular Medicine.[15][16] He has conducted several studies on running and heart disease,[17] and co-described the term Phidippides cardiomyopathy, a heart condition found in some high endurance athletes.[18][19][20] McCullough's other research projects have included the relationship between heart disease and kidney disease and risk factors for heart disease.[21][22] He is a member of the conservative advocacy group Association of American Physicians and Surgeons and has advocated for conspiracy theories promoted by the group.[23][3][24]
In August 2020, McCullough, Harvey Risch of the Yale School of Public Health, and co-authors published an observational study proposing an early outpatient treatment regimen for COVID-19 in the American Journal of Medicine.[34] Based on previous evidence, the article made recommendations for treating ambulatory COVID-19 patients, but presented no new evidence. The article was shared on social media, mainly by groups which had previously published COVID-19 misinformation, in posts falsely interpreting the publication as an official endorsement by the journal itself of hydroxychloroquine as a treatment for COVID-19.[35][36][37] The Ministry of Health of Brazil endorsed the article on its website, contributing to a severe COVID-19 misinformation problem in Brazil.[35][38][39] The article was criticized in letters to the editors;[40][41][42][43][44] the editors responded that the article included some "hopeful speculations ... What seemed reasonable last summer based on laboratory experiments has subsequently been shown to be untrue".[36][39]
McCullough and Risch were two of three witnesses called by committee chair Senator Ron Johnson to testify before a United States Senate Committee on Homeland Security and Governmental Affairs hearing on COVID-19 treatments held in November 2020. McCullough testified in support of social distancing, vaccination, and controversial treatments, including hydroxychloroquine. Ashish Jha, dean of the Brown University School of Public Health, called to testify by the ranking member, said the "clear consensus in the medical and scientific community, based on overwhelming evidence" is that hydroxychloroquine is ineffective as a treatment for COVID-19. McCullough said Jha was promoting misinformation and Jha's opposition to the drug was "reckless and dangerous for the nation".[26][45][46][47] Jha responded on The New York Times opinion page, "By elevating witnesses who sound smart but endorse unfounded therapies, we risk jeopardizing a century's work of medical progress."[48]
Posted on the Canadian online video sharing platform Rumble, McCullough gave an interview in April 2021 to The New American, the magazine of the right-wing John Birch Society, in which he advanced anti-vaccination messaging, including falsely claiming huge numbers of fatalities attributed to the COVID-19 vaccines.[24] In May 2021, McCullough gave an interview in which he made claims about COVID-19 and COVID-19 vaccines which were "inaccurate, misleading and/or unsupported by evidence", including that survivors cannot be re-infected and so do not require vaccination and that the vaccines are dangerous.[30]
During television appearances, McCullough has contradicted public health recommendations, including when asked about the aggressive spread of COVID-19 among children, by suggesting that healthy persons under 30 had no need for a vaccine,[31][49] and when asked about the relative merits of vaccination-induced immunity versus "natural" (survivor) immunity, by disputing the necessity of vaccinations to achieve herd immunity.[4][23][50][51] In December 2021, McCullough appeared on the Joe Rogan Experience promoting debunked conspiracy theories and misinformation (e.g. the COVID-19 pandemic was planned, the spike protein causes cell death, medical authorities are conspiring to illegitimately suppress hydroxychloroquine and ivermectin).[27][28][52]
McCullough has served as Chief Scientific Officer for The Wellness Company, a Florida-based dietary supplement and telehealth company, since its founding in June 2022.[53][54]
Rangaswami, Janani; Lerma, Edgar V.; McCullough, Peter A., eds. (2020). Kidney Disease in the Cardiac Catheterization Laboratory: A Practical Approach. London: Springer Nature. ISBN978-3-030-45413-5.
^ abEcarma, Caleb (July 8, 2021). "The Right-Wing Vaccine Rebellion Has Arrived on Campus". Vanity Fair. One Fox News medical expert, Peter McCullough, M.D., went so far as to steal the Joe Rogan argument, asserting on Wednesday that no college-age person in America should receive the COVID-19 vaccine. "Overall, the equation is very unfavorable for vaccination of anyone below age 30," he said during an appearance on Laura Ingraham's program Wednesday night. "Unless we really have a compelling case, no one under age 30 should receive any one of these vaccines."
^Hopkins, Thomas M. Burton and Jared S. (April 24, 2020). "FDA Warns Against Use of Chloroquine Outside of Clinical Trials". Wall Street Journal. ISSN0099-9660. Retrieved January 2, 2022. Preliminary research justifies deploying the drugs to treat mild coronavirus patients, before they require hospitalization, said Peter McCullough, a cardiologist at Baylor Scott & White Health in Dallas, which is studying hydroxychloroquine as a prophylactic in health-care workers. "We have to make some decisions now," he said.
^Hopkins, Denise Roland and Jared S. (April 28, 2020). "The Hunt for Covid-19 Drugs and Vaccines Becomes Even More Complex". Wall Street Journal. ISSN0099-9660. Retrieved January 2, 2022. Companies and researchers are also wrestling with how to balance testing experimental medicines as quickly as possible without sacrificing scientific rigor in clinical trials. For some studies, that means departing from the best standard for assessing a drug's safety and efficacy: measuring how one group of patients getting the drug fares against a control group receiving either the standard therapy or a placebo. A seven-week trial evaluating hydroxychloroquine as a prophylactic didn't wait the typical two months to manufacture a placebo in order to investigate as quickly as possible the antimalarial's safety and efficacy, said Peter McCullough, a cardiologist who is leading the trial at the Baylor Scott & White Health in Dallas. Instead, subjects who get the drug aren't randomly selected, and the normal control group will receive standard treatment, Dr. McCullough said.
^Weissmann, Leonardo; Naime Barbosa, Alexandre; Scarpellini, Bruno; Diament, Décio; Alexandrino Medeiros, Eduardo; Urbano Silva, Estevão; Mirna Loro Morejón, Karen; Rosalba Domingos Oliveira, Priscila; Silveira Bello Stucchi, Raquel; Porto Medeiros, Roseane; Cimerman, Sérgio; Constant Vergara, Tânia Regina; Arns Cunha, Clóvis (May 4, 2021). "Comments on the Pathophysiological Basis and Rationale for Early Treatment of COVID-19". The American Journal of Medicine. 134 (5): 341–342. doi:10.1016/j.amjmed.2021.01.004. PMC8095727. PMID33962707. Studies based only on pathophysiology are not adequate to prove the benefit of drug intervention...it is essential to follow the best scientific evidence and the principles of bioethics.
^Blake, Aaron (July 19, 2021). "Vaccine doubters' strange fixation with Israel". The Washington Post. A cardiologist on Fox News pointed to Israel's data while claiming "the delta variant really is not ... protected at all by the vaccines," and said, "There is no reason right now — no clinical reason to go get vaccinated."