COVID19 update, September 2, 2020: Dr. Seheult on clinical experiences with remdesivir and dexamethasone, and why medicine is more an art than a science; Israel situation update; herd immunity reconsidered

(1) In this video, Dr. Seheult briefly discusses three treatments that got EUA (emergency use authorization) from the FDA: remdesivir, dexamethasone, and convalescent plasma. He discusses his own clinical experiences treating patients with the first two (and promises a future update about convalescent plasma). He stresses that, while we may know from science what drugs may work, the key when treating actual patients is to watch and monitor them carefully. For example (it seems obvious in retrospect), a patient on the ventilator may be breathing very rapidly, and dissipate a lot of water vapor breathing out; this may lead to dehydration, a rise in Na+ levels,… unless compensated for by IV.

(2) (h/t: masgramondou) A guest poster at long-standing Libertarian group blog Samizdata discusses COVID19 tests, why they are not all equal, and how rapid and inexpensive reagent paper tests proposed by virologist Michael Mina could be a game changer, even if they are less accurate than RT-PCR. As a matter of fact, Dr. Seheult just released a brief infomercial about this:

And here is Dr. Mina speaking at greater length:

(3) A brief situation update from Israel. We continue to have as many as 2,000 new confirmed infections per day, and sadly our deaths are creeping towards the 1,000 mark. We have 845 COVID19 patients in hospital, of which 159 in moderate and 422 in severe condition, with 127 of the latter on respirators. (The “missing” 264 patients are presumably mild COVID19 cases actually hospitalized for something else.) Nearly 22,000 mild or asymptomatic cases are either at home or — if isolation at home is not feasible — in “coronahotels” about which I’ve blogged.

The good news: our case fatality rate is way down from the first wave. If we take May 25, with just 13 new cases (after that comes a steady increase), as the cutoff point between waves, we get a fatality rate of 281 deaths out of 16,734 verified infections=1.68%. From then until September 1, inclusive, we’ve accumulated another 101,804 verified infections and  676 deaths, which works out to a fatality rate of just 0.664% for the second wave.

While Israel tests fairly aggressively (as many as 36,000 in one day), serological testing still indicates an appreciable Dunkelziffer (infected “dark matter”) — as of early June, about 10:1. If this ratio (which is lower than what serological studies elsewhere have indicated) holds true, then as many as 1.2 million Israelis out of 8.67 million, or just shy of 14%, have been infected. That seems far from herd immunity, but not as far as people may think: consider the revised version of the higher-order herd immunity paper https://arxiv.org/abs/2005.04704v2,now retitled “Heterogeneity in susceptibility dictates the order of epidemiological models”.