* Biden: herd immunity in US unlikely before end of summer
* Treasury Sec. Yellen: US could reach full employment by 2022 with Biden plan
* South Africa stops use of AstraZeneca’s Covid-19 vaccine, citing new variants
* Protesters in Mynamar defy military, demand that civilian leader be reinstalled
* Senate prepares for speedy Trump impeachment trial
* German industrial output flat in December amid second coronavirus wave
* Oil prices recover to pre-pandemic level
* US payrolls posted weak rebound in January after sharp decline
* US 10-year rose to 1.19% last week, a one-year high: