According to Health Secretary Sajid Javid, there are currently 4,713 confirmed Omicron infections in the U.K. But in his statement to Parliament yesterday he added that the UKHSA has estimated the true current number of new daily Omicron infections to be around 200,000 (I assume in England, though he didn’t say). He added that this represents around 20% of the current estimated daily infections in England, including 44% in London. Note that these UKHSA figures are based on modelling that has not been released to the public.
Separately, the UKHSA has reported that just 10 people so far have been admitted to hospital in England with the Omicron variant (most of whom are double-vaccinated).
On transmissibility, early UKHSA estimates for the household secondary attack rate (the proportion of household contacts an infected person infects) using contact tracing data is 21.6% for Omicron and 10.7% for Delta. This suggests Omicron (incidentally, pronounced with a short ‘O’ as in orange, not a long ‘O’ as in over – omega is the Greek letter that signifies a long O) may be around twice as transmissible as Delta in the current population. However, to put this in context, note that the Alpha direct secondary attack rate in December 2020 was estimated by the UKHSA at 15.5%, while the Omicron estimate is based on a small number of infections and, according to the UKHSA, “may be influenced by improved ascertainment around Omicron cases”.