But Dr. Malone was not the lead author on the paper and, according to Dr. Acsadi, did not make a significant contribution to the research. While the paper stated that the technology could “provide alternative approaches to vaccine development,” Dr. Acsadi said none of the other authors would claim that they invented the vaccine.

“Some of his work was important,” said Dr. Alastair McAlpine, a pediatric infectious disease doctor based in Vancouver, British Columbia, “but that’s a long way away from claiming to have invented the technology that underpins the vaccines as we use them today.”

The vaccines “are the result of hundreds of scientists all over the world, all combining to come together to form this vaccine,” Dr. McAlpine said. “It was not one individual or the pioneering work of an individual person.”

A spokeswoman for Penn Medicine said, “We have been excited to witness the deployment of the vaccines in the global fight against the virus and the well-deserved global recognition for Drs. Kariko and Weissman’s decades of visionary basic science research.”

Dr. Malone pushes back against the criticism directed at him by scientists, researchers and journalists, and dismisses the dozens of fact-checks disputing his statements as “attacks.”

He also continues to repeat his claims, with the help of his wife, Dr. Glasspool Malone, who is trained in biotechnology and public policy. She writes, he said, more than half of the articles posted onto his Substack newsletter — which is awash in conspiracy theories about the Covid-19 vaccines. Recent articles include “The illusion of evidence-based medicine” and “How does it feel to be vindicated?”

Dr. Malone said he did not align himself with any particular political party. But in recent months, he and his wife have made numerous stops at popular conservative conferences, like Hereticon, the Peter Thiel-backed conference in Miami for Silicon Valley’s self-proclaimed contrarians, and the “Defeat the Mandates” march in Washington.