Experts testified during a hearing in Washington.

Members of Congress on Nov. 13 were warned during a hearing about the DNA fragments that have been detected in the Pfizer-BioNTech COVID-19 vaccine.

Dr. Robert Malone, who helped invent the messenger RNA (mRNA) technology that the companies used for the shot, was among the witnesses testifying to a hearing in Washington convened by Rep. Marjorie Taylor Greene (R-Ga.).

The vaccine includes a DNA sequence called Simian Virus 40 (SV40) that was not disclosed to at least some regulators. The sequence leaves behind residual DNA that could cause problems, Dr. Malone told the hearing.