Is the British case really late?

latest REACT reportRegular studies of the UK’s largest COVID-19 infection rate appear to provide the coveted good news. The authors of the report suggest that the combination of national measures and regional blockades may have played a role in slowing the spread of the virus.

The daily number of cases in the UK is still increasing, but at a slower rate. The most important R numbers may have dropped from a high of 1.7 in late August to the current 1.1, but there is great uncertainty in both numbers.

Between September 18th and 26th, REACT researchers at Imperial College London randomly selected more than 84,000 people nationwide to test. Of these swab tests, 363 returned positive, suggesting that there were more than 400,000 infections in the United Kingdom. This is about 1 in 140, a significant increase from about 1 in 800, which was found to be infectious in a previous survey a month ago.Spread slowing is a positive step, but the numbers still reflect a worryingly high prevalence. Coronavirus In the community.

The report also emphasizes that the prevalence of the virus has increased in recent weeks across all regions and all age groups. This inevitably leads to more hospitalizations and ultimately death in the coming weeks.

It may seem counterintuitive that R could drop, which sounds like good news, but the daily number of cases continues to grow and is definitely bad news.

R is the number of new infections that an infected person will infect on average during the period of infection. When R exceeds 1, at least one new infection will occur and the epidemic will continue to spread. R measures how quickly the disease spreads throughout the population. According to the REACT report, R dropped from 1.7 to 1.1. This is good news, but as long as the R value is above 1, the number of infected people will continue to grow.

This decrease in diffusivity is consistent with other data sources that can estimate epidemic growth. HospitalizationFor example, the growth rate has been declining recently, suggesting that the transmission rate is lower than it was about a week ago. Increasing number of calls to NHS and emergency services It’s been late recently..

Much has been done from the harsh predictions made by Sir Patrick Valence, the government’s chief scientific adviser at the time, at a briefing in early September.Apocalyptic graphics suggested that Britain may be facing if the current growth of the case continues. 50,000 new cases daily by mid-October.. However, while the increase in the number of cases is significant, it does not seem to support this prediction. This shows a decline in growth rates in line with REACT studies.

Ironically, it may have been this enhanced message that contributed to and slowed the spread of the public’s new compliance with social distance, hand washing and wearing face covers. Fortunately, this is a self-defeating prophecy.

Which data?

Of course, care must be taken with any data source that can estimate epidemic growth. Cases show the latest status of what’s happening, but case data is probably not the most reliable source due to processing delays and difficulty getting tests. Hospitalization seems to be a more reliable indicator — not to be missed by many who really need to go to the hospital — but usually more than a week after being infected with the virus before being hospitalized. There is a delay.

There is also debate as to whether people were hospitalized for COVID or simply tested positive after being hospitalized for another illness. Death seems to be the most reliable indicator — it should be very clear if someone died — but even with this metric, Controversy It can be said that someone died of COVID for how long after being tested positive.

Limit these numbers to death Within 28 days of positive test Although we have eliminated many of the possibilities of overestimation (potentially out of balance towards underestimation), there is still a significant delay between case and death. That is, the mortality data is not up to date.

REACT is often regarded as a reliable tool due to the large number of people sampling, but this study has its own problems. Data is sampled in a short period of time (called a round) rather than continuously. So I’m not sure what’s going on in the middle of the rounds.

Applying independent growth rates to individual data rounds, we can see that R declines from the beginning of September to the end of September. However, assuming growth rates were constant over the test period, similarly good fits could have been obtained and R could have been stable at around 1.5 throughout September. Data fluctuate, so it is not advisable to draw firm conclusions based on just one study.

Recent declines in cases, hospitalizations, and triage data growth in combination with REACT studies appear to suggest that this sharp upward trend has not continued. However, if the restrictions that affect it are tightened, Northern England proves, We haven’t been on this trendy wave yet.

This article will be republished from conversation Under a Creative Commons license.Read Original work..