The RT value is another play on words. Politicians love new words and theories they can use to explain and support their agenda. Of course after hearing the same thing over and over we translate that info into facts.
What the reproduction number can and can’t tell us about managing COVID-19.
www.nature.com
"But fascination might have turned into unhealthy political and media fixation, say disease experts.
R is an imprecise estimate that rests on assumptions, says Jeremy Rossman, a virologist at the University of Kent, UK. It doesn’t capture the current status of an epidemic and can spike up and down when case numbers are low. It is also an average for a population and therefore can hide local variation. Too much attention to it could obscure the importance of other measures, such as trends in numbers of new infections, deaths and hospital admissions, and cohort surveys to see how many people in a population currently have the disease, or have already had it.
“Epidemiologists are quite keen on downplaying
R, but the politicians seem to have embraced it with enthusiasm,” says Mark Woolhouse, an infectious-diseases expert at the University of Edinburgh in the United Kingdom, who is a member of a modelling group that advises the British government on the pandemic. “We’re concerned that we’ve created a monster.
R does not tell us what we need to know to manage this.”
The drawbacks of an average
An important aspect of
Rt is that it represents only an average across a region. This average can miss regional clusters of infection. Conversely, high incidences of infection among a spatially distinct smaller subsection of a population can sway a larger region’s
Rt value. For instance, Germany’s national
Rt value jumped from just over 1 to 2.88 in late June (later revised down to 2.17) largely because of an outbreak in a meat-processing plant at Gütersloh in North Rhine-Westphalia (see 'Germany's Regional Outbreaks'). The Robert Koch Institute noted that national infections overall were still low, which is why the local outbreak had such an effect on the country’s
Rt, which had dropped below 1 again by the end of June. This makes it unlikely that
Rt would be used to steer local lockdown policy in Germany, Schaade says. “If the rolling mean of
R was at 1.2 for a few weeks, then that would show there was a problem that needed attention, even if case numbers were low.” But in practice, researchers find out about local outbreaks before that because of a reported spike in cases, not because of changes to
Rt. Germany has ongoing surveillance and public reporting of transmission levels in 400 counties.
www.foxnews.com
apnews.com
