A new U.S. government commission on vaccine safety has not died the quick death immunization advocates might have wanted. It is still in the works, according to the shot critic who would likely head up the effort.

President Donald Trump told Robert Kennedy Jr. that he expected an "uproar" from pharma when news of the commission first broke—but promised he would not "back down" from his plans, Kennedy said Wednesday.

At an hourlong press conference Wednesday in Washington, D.C., Kennedy Jr. said the White House had contacted him three times since reports broke on his meeting with then-President-elect Trump last month. Kennedy emerged from the meeting saying Trump wanted him—a frequent vaccine critic who has espoused discredited data questioning their safety—to lead a commission investigating their safety.

Trump’s team denied the claim at the time, but on Wednesday, Kennedy revealed new details about the discussions.

"They tell me that they are still going forward with a commission," Kennedy said, referencing what he previously described as a group that would look into "vaccine safety and scientific integrity."

Kennedy said the president told him he "knew that the pharmaceutical industry was going to cause an uproar about this and was going to try to make them back down."

Trump said "I’m not going to back down," Kennedy continued. Trump "knew many people who thought and believed their children were injured by vaccines."

The political scion went on to say the commission would be "made up of Americans with the highest integrity" to review the science behind immunizations.

This came despite the existence of the CDC’s Advisory Committee on Immunization Practices, a "group of medical and public health experts that develop recommendations on use of vaccines" for the nation, according to its website. Nonetheless, Kennedy blasted the federal agency as a "cesspool of corruption" on Wednesday.

Initial news of the commission plans sparked an immediate backlash as industry and public health experts argued its mere existence would drum up vaccine safety doubts among the U.S. public.

In the wake of that meeting, and amid other developments, 350 medical and patient organizations wrote to the president to stress the simple point—"vaccines are safe." In their letter, the medical groups included dozens of pages of research documenting the safety of routine immunizations.

Despite Trump’s "vaccine hesitant" views, Pew Research Center recently found the vast majority of Americans think the benefits of MMR vaccinations outweigh their potential risks.