A UN-backed agency has struck a deal for nearly 30 generic drugmakers to make low-cost versions of Merck & Co's Covid-19 pill molnupiravir for poorer nations, widening access to a drug seen as a weapon in fighting the pandemic.

The antiviral drug, which in December received emergency approval in the United States, reduces hospitalizations and deaths of high-risk patients by around 30 percent, according to clinical trial results.

The agreement, negotiated by the UN-backed Medicines Patent Pool (MPP) with Merck, allows 27 generic drugmakers from...