COVID: mostly asymptomatic or presymptomatic in nursing homes

 A recent multi-state study looked at the asymptomatic/presymptomatic SARS-CoV-2 infection rates in nursing homes, finding that 60% were in these categories (see covid asymptomatic nursing homes jamaintmed2020 in dropbox, or doi:10.1001/jamainternmed.2020.5664)

Details:

--data from Genesis HealthCare, a multi-state long-term care provider with 350 skilled nursing facilities (SNFs), accessing their electronic medical data logs of infection dates and results, from March 16 til July 15. 

    --given the variability of testing in SNFs by region/state, they assessed only SNFs with at least 1 point-prevalence survey, which included 182 SNFs

--all patients had nursing assessments at least twice a day, recording symptoms

--patients were considered symptomatic if they had new suggestive Covid-19 symptoms within 5 days of first positive test; presymptomatic if no suggestive symptoms in those 5 days before testing but then developed suggestive symptoms within 14 days; and asymptomatic if no symptoms from 5 days pre-test to 14 days post-test

--County background rates of SARS-CoV-2 prevalence: 5% located in top tier, 20% in middle tier, and 75% in lowest tier

Results:

--173 SNFs with 5011 residents who had positive SARS-CoV-2 PCRs (will confine the results to SNFs that had facility-wide testing, 96% of the SNFs analyzed)

--SARS-CoV-2 Infection rates:

    --symptomatic:  1993 residents (40%)

    --presymptomatic:  969 residents (19%)

    --asymptomatic:  2049 residents (41%)

--By counties: those in the highest SARS-CoV-2 prevalence had higher combined counts of asymptomatic and presymptomatic cases

Commentary:

--this study reinforces the very high prevalence of asymptomatic/presymptomatic SARS-CoV-2 infections in SNFs. and reinforces the importance of routine testing in the absence of any suggestive symptoms

--and, though nursing homes are particularly problematic locations (lots of older people with lots of comorbidities, and often in very close proximity to each other, as well as staff with insufficient PPE), this study should be viewed in the context of other studies:

    --a large review of studies found that 40-45% of those with positive PCR tests for SARS-CoV-2 are asymptomatic (see covid asx infection review AIM2020 in dropbox, or doi:10.7326/M20-3012), which includes many different sites of care (nursing homes, homeless shelters, cruise ships, general populations, inmates, hospitals...)

--this study was also mostly of SNFs in the lowest tier of country-specific SARS-CoV-2 prevalence rates (75% in lowest tier), with fewer asymptomatic/presymptomatic people in that tier. so, might be a significantly bigger issue as Covid cases surge

so, this study represents "more of the same": SARS-CoV-2 infections occur very, very commonly in those who are symptomatic or presymptomatic, which really means that in order to get over this horrific pandemic:

--we should NOT assume that there is lots of utility in screening people by symptoms, fever, etc.  We will miss most of the people this way (and SARS-CoV-2 seems to be very contagious in presymptomatic people in the day or so prior to symptoms)

--and we really need to assume everyone is positive (universal precautions, as we do with HIV), and continue aggressive PPE use/distancing/etc (despite the widespread lure away from this by "covid-fatigue")

--and, testing, testing, testing (followed by appropriate isolation of infected people)

we also know that this is all going to get much harder, with the current Covid case surge increasing at a time of colder weather (and more time around people in homes, fewer outdoors) and more viral infections (colds, flu)....

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as a relevant aside, another study was just published with mathematical modeling showing dramatic benefits from wearing masks and social distancing (see covid case for universal masks natmed2020 in dropbox, or doi.org/10.1038/s41591-020-1132-9). Briefly, deaths from Covid-19 by 28 Feb 2021:

--with continued relaxation off social distancing mandates: 1,053,206 cumulative deaths

--with social distancing mandates reinstated when there is a threshold of 8 deaths/million population (ie beginning more restrictions at that threshold): 511,373 deaths based on the 45 states expected to reach this 8 death/million threshold (this scenario would also result in 80,798,356 fewer estimated infections). and all states would reach an R_effective of >1

--with universal mask scenario where there was in fact 95% mask use in public: cumulative death toll of 381,798, saving 129,574 deaths (vs the mandate-easing scenario), with 9 states forecasted to exceed 8 deaths/million people (California, Colorado, Massachusetts, New Jersey, New Mexico, North Carolina, North Dakota, Pennsylvania and Rhode Island), and 17,408,353 fewer infections

--and, universal mask use (but in fact 85% mask use in public) could save 95,814 deaths

so, with this virulent, highly transmissible virus, these numbers of infections and deaths are huge (these numbers are actually so high that it is hard to comprehend their true real-world meaning!!), again reinforcing the extraordinary importance of:

-- mask usage and safe distancing

-- really mandating distancing/masks especially when certain thresholds as met  (in the case above, when the 8 deaths/1 million people is exceeded)

-- and the extreme importance of our upcoming elections: we desperately need a president who:

    --is not just a climate-change denier but a coronavirus denier: Trump is openly attacking Fauci for contradicting the "we are rounding the corner" on coronavirus 

    --and, he is issuing an executive order that would allow him to replace anyone in the government who is not lock-step behind him (eg, Fauci et al, see https://www.cnn.com/2020/10/24/opinions/trump-executive-order-reclassify-government-employees-schedule-f-garrett/index.html )

         --ie, converting his "bully pulpit" to an "unquestioned, dictatorial pulpit" by the bully-in-chief

    --and, if he continues as president, the above numbers of infected people/deaths by 28Feb (4 months from now) will likely blossom well beyond that in the longer term

pretty scary stuff....

geoff

 

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