When did the new covid started On 26 November 2021 that WHO declared that the world was facing a new variant of concern: Omicron. It would go on to change the trajectory of the COVID-19 pandemic. Emerging evidence was quickly shared by scientists from Botswana, Hong Kong and South Africa and discussed in a special meeting of WHO’s Technical Advisory Group for Virus Evolution (TAG-VE). Experts at the meeting worried about the large number of mutations present in this variant, which differed greatly from the other variants that had been detected so far. Early data showed Omicron’s rapid spread in some provinces in South Africa and an increased risk of reinfection compared to the previously circulating variants. Just hours later, WHO declared this new variant a variant of concern: we were dealing with something new, something different, and something that the world had to quickly prepare for. The Omicron effect Omicron was quickly identified as being significantly more transmissible than Delta, the preceding variant of concern. Within 4 weeks, as the Omicron wave travelled around the world, it replaced Delta as the dominant variant. Countries which had so far been successful in keeping COVID-19 at bay through public health and social measures now found themselves struggling. For individuals, the greatest price was paid by those who were at risk of severe disease but not vaccinated, and we saw hospitalizations and deaths rise in a number of places around the world.