“Among the known Omicron sub-lineages (i.e. BA.1, BA.2, BA.2.12.1, BA3, BA.4, and BA.5), BA.4 and BA.5 are least susceptible to vaccine-elicited neutralizing antibodies,” said Dr. Pei-Yong Shi, professor, UTMB Chair in Innovations in Molecular Biology. Both variants have their own specific mutations including ones affecting the spike protein of the virus—the part responsible for attaching to human cells and infecting them. “Vaccine boosters will continue to prevent severe diseases and deaths,” Shi said. “Wearing masks in events with a lot of people helps to reduce the risk of Omicron infections.”