U.S. boosters surge to all-time high on Omicron fears ReutersOmicron Propels US Booster Drive in Colorado and Michigan BloombergCould numerous boosters make future Covid vaccines less effective? Experts weigh in msnNOWWith the new Omicron variant, should you wait to get your booster shot? CTV NewsOmicron variant, booster shots, case count: Tracking COVID-19 in Kentucky, Indiana WLKY Louisville