McCullough advocated for early treatment using the discredited treatments
hydroxychloroquine and
ivermectin... 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.
[23] 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