Manufacturers’ Reprieve Could Be Ruined by Omicron—or Not

American manufacturers’ supply-chain problems began to ease last month. The risk is that the Omicron variant of Covid-19 could quickly turn that into old news.

The Institute for Supply Management on Wednesday said its index of factory activity rose to 61.1 in November from October’s 60.8, an indication that manufacturing continues to grow rapidly. Anything over 50 indicates expansion.