[quote geekaMaxima]@weepingwillow22 It would make sense to rely on up-to-date covid-19 test results if the test itself was reliable AND testing was extensive and uniformly available in all locations AND all test results were localised accurately to small areas. None of those things are true for the UK testing scheme, so unfortunately the models that use test results are based on measurements with a very high degree of error.
The net result is that such models are absolutely NOT more accurate than models based on 3-week-old death data, particularly when supplemented with recent seroprevalence tests of blood donations. At best, they might be equally accurate, but the reverse is much more likely to be true (i.e. the death-based models are more accurate), and the death-based models have been more accurate in predicting things like rises in regional hospital admissions over the last few weeks
In some countries, the test-based models are best. The UK is not one of those countries.[/quote]
I agree with you about the limitations of the UK testing approach used for the zoe research. However I think the Cambridge modelling also has significant limitations especially when looking at data at the regional level.
www.sciencemediacentre.org/expert-reaction-to-data-from-the-mrc-biostatistics-unit-at-the-university-of-cambridge-nowcasting-and-forecasting-covid-19/
Prof Matt Keeling, Professor of Populations and Disease, University of Warwick, said:
'So what is generating these differences? The MRC Biostatistics Unit has considered deaths due to coronavirus as their main quantity of interest – in London this is falling far more rapidly than other measures of the outbreak such as hospital admissions.
“What this study highlights is that London is experiencing a subtly different epidemic to other regions of the country, with a more rapid decline and different relationships between ICU occupancy, hospital occupancy and deaths. This is clearly something that needs to be understood in more detail, as it may be important for how different areas of the country exit from lock-down.
“I am extremely worried about the media message that ‘London could be coronavirus free in days’. At the moment there is way too much uncertainty in factors such as asymptomatic transmission or infection in the health-care worker population to make this claim. Londoners have made a brilliant effort in adhering to lock-down advice, and bringing the infection under control. If people think London is coronavirus-free that could be dangerous, and could lead to complacency, undermining all the struggles and sacrifices that everyone has made so far. A relaxation of vigilance could easily see R increase'