Federal agencies and vaccine developers are facing intense political pressure for a Covid-19 vaccine by November, but they insist that they will be guided by science. | Andrea Ronchini/NurPhoto via Getty Images

The CDC wants hospitals to prepare to deliver a vaccine by November, but vaccine makers are pledging not to rush approval.

Nine companies leading the charge to develop a Covid-19 vaccine released a pledge Tuesday to stick to the science in the development and licensing of a vaccine in what appears to be an attempt to preempt pressure from the White House to rush vaccine approval before the November election.

The vaccine makers said they are committed “to developing and testing potential vaccines for COVID-19 in accordance with high ethical standards and sound scientific principles.”

The statement comes as the Trump administration is expecting significant movement on a Covid-19 vaccine before