It brought understandable concern when it was revealed that an estimated 200,000 people a day are getting infections with Omicron, but just 4,713 cases have been confirmed in the UK so far. What does this figure tell us about the surge's trajectory?
A full genetic analysis of the person's sample is required to confirm a Covid case. The UK Health Security Agency's figure of 4,713 Omicron cases was out of date due to the fact that it can take up to two weeks to return a viral sequence.
The number of Omicron cases can be estimated by looking at the S gene target failure. A quick indication of whether Omicron is present in a sample is provided by some of Omicron's genetics. Between a third and half of the UK testing labs have the technology to do this. This gives a way to estimate the proportion of UK cases that are Omicron, and how quickly it is passing the Delta variant.
The latest figures show 54,661 new positive Covid-19 cases reported across the UK on Monday, though it's important to remember that it takes time to develop symptoms and seek a test. Approximately 11,000 daily Omicron cases are thought to be the 20% of UK cases that are now Omicron.
This only shows confirmed cases of people who have tested positive. The true number of daily infections is unknown because not everyone with Covid gets tested. The Office for National Statistics survey data is so revealing because it shows the true proportion of Covid-19 in the population at any given time.
According to the UKHSA, Javid's 200,000 a day figure is due to the fact that there were around 78,000 Delta infections on 7 December, equating to approximately 23,000 daily Omicron infections. The UKHSA estimated that 207,000 people were affected by Omicron on December 13th. Like the famous tale of the wheat and chessboard, regular doubling rates quickly add up to large numbers.
If Omicron infections continue to grow at their current rate, there could be 1 million daily infections by the end of December, according to the UKHSA. It makes sense that a figure of this magnitude would prompt the public to take precautions, but it may also prompt them to take precautions.
Hospital staff, teachers, supermarket workers and lorry drivers are some of the growing numbers that could have to be isolated.
It's not clear whether these predictions will come to pass. There are huge uncertainties regarding the extent to which T cell immunity from previous infections will protect against severe disease and hospitalisations. At some point, infections may have been exposed to the new variant and/or received a booster jab in the UK that will begin to slow, although immunity takes several weeks to develop. There is a suggestion of a peak in January.
If cases keep doubling, we will hit herd immunity. fection cannot keep doubling forever, he said. The outbreak of Omicron will burn itself out if there are not enough people to catch it, but we want to avoid that.
herd immunity is not a good public health strategy. This wasn't a viable option back in March 2020 and it's not a viable option now.
The doubling rate is changing all the time and will continue to do so according to the UKHSA. If Omicron cases are doubling every two days, we should expect a rapid increase in cases confirmed by positive PCR tests very soon, because the data in the days to come should clarify the situation.
What does this mean for the surge? Experts advocate a cautious approach. If additional measures are brought in, it would take a week or so to get a fall in daily cases because of the delay between being exposed to the virus and getting tested. It would take even longer to realise the impact on hospitalisations and deaths.
