Addressing concerns that the development of coronavirus vaccines for COVID-19 could be hurried due to politics, Dr. Anthony Fauci cautioned that their development should not be rushed.

In an interview with Reuters published on Monday, Fauci -- the director of the government's National Institute of Allergy and Infectious Diseases (NIAID) -- said that "[t]he one thing that you would not want to see with a vaccine is getting an EUA (emergency use authorization) before you have a signal of efficacy."

His comments came a day after the Food and Drug Administration (FDA) granted an EUA for the use of convalescent plasma to treat COVID-19. That authorization is controversial because the data is not supported by robust clinical testing.

Gloved hands filling a syringe from a vial.

Image source: Getty Images.

There is also growing concern that the current presidential administration will exert pressure on the FDA to approve a vaccine candidate prior to the Nov. 3 election.

Among other risks, approving a vaccine before it has been fully and properly researched could badly affect the prospects for candidates still in development. "One of the potential dangers if you prematurely let a vaccine out is that it would make it difficult, if not impossible, for the other vaccines to enroll people in their trial," said Fauci.

Several promising vaccine candidates are now in late-stage clinical trials. However, it is unlikely that the process for any of them will wrap up before the election. Moderna (MRNA 1.70%) is arguably the most prominent of these; its mRNA-1273 has demonstrated high efficacy in earlier phases of testing. The Moderna candidate is the leader among messenger RNA-based solutions for a coronavirus vaccine.

The share performances of companies currently testing such vaccine candidates were mixed on Tuesday. Moderna was among the gainers, rising 2.1% on the day to eclipse the 0.4% increase of the S&P 500 index.