Thread by @AliHMokdad

@IHME_UW now projects a total of 415,090 #COVID19 deaths by Jan 1st (most likely scenario); 611,784 (worst case scenario); and 298,589 (best case scenario). 1/22
covid19.healthdata.org/united-states-…

The new 415,000 US #COVID19 death projection by January 1 represents a more than doubling of deaths over the past six months. 2/22

But no matter where the US is now, we have the tools to save thousands of lives moving forward. The science is clear and the evidence irrefutable: mask-wearing, social distancing, and limiting social gatherings all help prevent infection. 3/22

Increasing mask use to the levels seen in Singapore would decrease the cumulative US death toll to 298,589, or 116,501 lives saved compared to the reference scenario. 4/22

If a herd immunity strategy is pursued, (i.e. no further government intervention is taken from now to Jan 1), then the death toll could increase to 611,784 by Jan 1. Compared to the reference scenario, this would be 196,694 more deaths from now to the end of the year. 5/22

Evidence is consistently emerging that the US is becoming less vigilant. Mobility has been rising since August 1, albeit slowly. 6/22

Mask use has also been declining steadily since August 1. Only six states have mask use over 50% at this point: Alaska, California, Florida, Hawaii, Texas, and Virginia. 7/22

Preventive measures are especially important as fall weather begins. It is clear that #COVID19 likes colder temperatures, much like how we are prone to pneumonia in colder temperatures. 8/22

The decline in national case numbers seen since late July flattened in the last week. 9/22

Daily deaths have been relatively constant around 850 per day over the past week so that #COVID19 remains the number two cause of death in the US. 10/22

States where the combination of data on cases, hospitalizations, and deaths suggest that transmission is increasing has shifted to Alabama, Colorado, Hawaii, Kansas, Missouri, New Jersey, New York, Virginia, and West Virginia. 11/22

States where the #COVID19 death rate is over 4 per million are in a contiguous block from Texas through to South Carolina. 12/22

We expect the #COVID19 daily death rate in the US, because of seasonality and declining public vigilance, to reach nearly 3,000 a day in December. 13/22

The large increase in daily deaths expected in late November and December is driven by continued increases in mobility, declines in mask use, and – most importantly – seasonality. 14/22

We estimate the impact of seasonality using the trends in the Northern and Southern Hemisphere. Countries such as Argentina, Chile, southern Brazil, and South Africa had much larger epidemics than expected based on mobility, testing, and mask use. 15/22

The statistical association between COVID-19 transmission rates and pneumonia seasonality patterns is strong and is the basis for our estimate of the magnitude of the seasonal increase that is expected. 16/22

Clinical experience suggests that case management of #COVID19 has improved through oxygenation/ventilation methods and use of dexamethasone and remdesivir. 17/22

This improved management would manifest itself as a reduction in the infection-fatality rate at each age. We have looked for statistical evidence of this shift in two ways. 18/22

First, we have examined the #COVID19 admission-fatality rate – the number of deaths divided by hospital admissions. To date, the admission-fatality rate has remained constant since April. 19/22

This could be explained by two possible factors: either there is no change in the infection-fatality rate or the infection-fatality rate has declined and hospitals are admitting only more severe patients over time. 20/22

Second, we have looked at the directly measured infection-fatality rate using seroprevalence studies. To date, we have not detected any statistically significant decrease in the infection-fatality rate. 21/22

We will continue testing on a regular basis for statistical evidence of the infection-fatality rate declining. Stay tuned. 22/end
covid19.healthdata.org/united-states-…