Merigan's research first focused on human viral pathogenesis, basic and clinical studies of interferon, and then developing the first systemically active antiviral drugs including those effectively treatIng HIV/AIDS, several herpesviruses and hepatitis B.
He did his internship and residency on the Harvard medical services at Boston City Hospital and then moved to the National Institutes of Health in Bethesda where he trained for 3 years in protein chemistry in Nobelist Christian Anfinsen's laboratory.
His first sabbatical leave was spent at the MRC Common Cold Unit in Salisbury and London, England in 1970 with David Tyrell and Sir Christopher Andrews under a Guggenheim fellowship.
The antivirals he collaborated in the development of include those directed against herpesviruses (CMV, VZ, and HSV), hepatitis B, papovaviruses, rhinoviruses, HIV, and rabies.
His group also developed, tested, and held patents through Stanford University on the methods for monitoring the effects of treatment of HIV which are still used today.
He gave a number of named endowed lectureships in the US and elsewhere and also on several occasions testified before congressional committees on the subject of oncoming needs for federal funding for both AIDS and cancer research.
His testimony lead directly to Tip O’Neil's putting forth a bill which both houses of congress and President Reagan quickly signed off on creating the NCI's Frederich Cancer Center.
[3][4] Merigan was also interested in entrepreneurship throughout his career and served on the scientific advisory boards of a number of big pharma and biotechnology companies, Including those of Cetus Corporation in 1979.
In 2004, Merigan assumed active emeritus status in the Stanford faculty, celebrated by a Festschrift in his honor later published in the Journal of Infectious Diseases.
[2] The following year he and his first wife endowed the Thomas C. and Joan M. Merigan Chair in infectious diseases at Stanford, currently held by David Relman.