Several COVID-19 vaccine developers, including Pfizer Inc, Johnson & Johnson, and Moderna Inc, plan to issue a public pledge not to seek government approval until their vaccine candidates are proven to be safe and effective, the Wall Street Journal reported on Friday.

The companies would pledge to adhere to high scientific and ethical standards in the conduct of clinical studies and their manufacturing processes, the Journal report said, citing the draft of a joint statement that is still being finalized.

The companies might issue the pledge as soon as early next week, the report added, citing two people familiar with the matter.

The news comes amid rising concerns that political pressure ahead of the Nov. 3 election could weigh on the safety and effectiveness of a potential vaccine for the respiratory illness.

White House Press Secretary Kayleigh McEnany said on Thursday that even though the stakes are high for President Donald Trump, who is squaring off against former Vice President Joe Biden, there is no political pressure on the U.S. health regulator to quickly approve a vaccine.

AstraZeneca Plc, Pfizer, and Moderna are among those farthest along in the race to develop vaccines to prevent COVID-19 infection or limit its severity, with its candidates in late-stage clinical trials.

Pfizer, Moderna, and Johnson & Johnson did not immediately respond to Reuter's request for comment.