Variant and Vaccine Updates Why are there different variants of COVID-19? Like any virus, COVID-19 can and will change over time. As of December 20, 2021, about 97% of analyzed cases are caused by the Delta variant while the remaining 3% are due to the Omicron variant.3 While the World Health Organization announced the Omicron … Continue reading COVID-19 Updates: December 17, 2021