Several drug makers developing Covid-19 vaccines plan to issue a public pledge not to seek government approval until the shots have proven to be safe and effective, an unusual joint move among rivals that comes as they work to address concerns over a rush to mass vaccination, The Wall Street Journal reports.

A draft of the joint statement, still being finalized by companies including Pfizer Inc., Johnson & Johnson and Moderna Inc., commits to making the safety and well-being of vaccinated people the companies’ priority.

“We believe this pledge will help ensure public confidence in the Covid-19 vaccines that may ultimately be approved and adherence to the rigorous scientific and regulatory process by which they are evaluated,” says the draft statement, as mentioned in the report.

The news comes days after the U.S. federal government told states to prepare for a coronavirus vaccine to be ready to distribute by November 1.

There are now rising concerns that political pressure ahead of the November 3 election in the U.S. could weigh on the safety and effectiveness of a potential vaccine against the coronavirus.