The World Health Organization (WHO) said that a more transmissible COVID-19 Omicron sub-variant will increase around the world as the U.N. health body reported a decline in overall cases in the past week. Maria Van Kerkhove, the WHO’s COVID-19 technical lead, told reporters on Tuesday that four different versions of the Omicron variant—first described and controversially named in November—are being tracked around the world. The BA.2 sub-variant, which is believed to be more contagious, will likely become more common worldwide, she said. “BA.2 is more transmissible than BA.1 so we expect to see BA.2 increasing in detection around the world,” Van Kerkhove told reporters during a WHO briefing. There is no indication, she said, about whether the sub-variant is more severe than the original. Danish researchers discovered BA.2 is about 1.5 times more transmissible than BA.1 and can infect fully vaccinated and boosted individuals with ease. Making note of the …