Mark Geier

Who is Mark Geier?

Mark R. Geier is a self-employed American physician, geneticist and controversial professional witness who has testified in more than 90 cases regarding allegations of injury or illness caused by vaccines. Since 2011, Geier's medical license has been suspended or revoked in every state in which he was licensed, over concerns about his autism treatments.

Geier and his son, David Geier, are frequently cited by proponents of the claim that vaccines cause autism. Geier's credibility as an expert witness has been questioned in 10 court cases. In 2003, a judge ruled that Geier presented himself as an expert witness in "areas for which he has no training, expertise and experience." In other cases in which Geier has testified, judges have labeled his testimony "intellectually dishonest," "not reliable" and "wholly unqualified." Another judge wrote that Geier "may be clever, but he is not credible."

Geier's scientific work has also been criticized; when the Institute of Medicine reviewed vaccine safety in 2004, it dismissed Geier's work as seriously flawed, "uninterpretable", and marred by incorrect use of scientific terms.