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CDC Antibody Studies Confirm Huge Gap Between COVID-19 Infections and Known Cases
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Michael Ejercito
Jun 29, 2020, 10:06:09 AM6/29/20
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http://reason.com/2020/06/28/cdc-antibody-studies-confirm-huge-gap-between-covid-19-infections-and-known-cases/
CDC Antibody Studies Confirm Huge Gap Between COVID-19 Infections and Known
Cases
The difference implies that the virus is much less deadly than it looks, but
it also makes contact tracing a daunting challenge.
JACOB SULLUM | 6.28.2020 6:35 PM
COVID-19-antibody-tests-Newscom
(Marijan Murat/DPA/Picture Alliance/Newscom)
Newly published antibody test results from half a dozen parts of the country
confirm that COVID-19 infections in the United States far outnumber
confirmed cases. The ratio of estimated infections to known cases in these
studies, which the U.S. Centers for Disease Control and Prevention (CDC)
reported on Friday, range from 6 to 1 in Connecticut as of early May to 24
to 1 in Missouri as of late April.
These results confirm something we already knew: The COVID-19 infection
fatality rate—deaths as a share of all infections—is much lower than the
crude case fatality rate—deaths as a share of known cases. That is bound to
be true when testing is limited and a virus typically produces mild or no
symptoms. At the same time, the CDC's antibody studies imply that efforts to
control the epidemic through testing, isolation, quarantine, and contact
tracing will not be very effective, since they reach only a small percentage
of virus carriers.
The CDC analyzed blood samples drawn for routine tests unrelated to COVID-19
from patients in New York City, Connecticut, South Florida, Missouri, Utah,
and western Washington state. Although these samples may not be
representative of the general population, they provide a clearer picture of
virus prevalence than screening limited to people who sought virus tests
because they had symptoms consistent with COVID-19 or because they were in
close contact with known carriers.
In New York City, where the samples were drawn from March 23 through April
1, nearly 7 percent tested positive for COVID-19 antibodies, implying that
infections outnumbered reported cases during that period by 12 to 1. The
prevalence estimated by a state-sponsored antibody study conducted from
April 19 to April 28 was three times as high, although the ratio of
estimated infections to known cases (about 11 to 1), was similar. The
difference in estimated prevalence can be at least partly explained by the
spread of the virus between early and late April.
The gap between the two estimates may also be partly due to differences
between the samples used in the studies. The CDC study was based on patients
whose doctors ordered routine blood tests, while the New York State
Department of Health study used blood drawn from randomly selected shoppers.
Infections might have been unusually common among people who ventured out to
stores during the study period, either because they were more likely to
encounter carriers or because they had already recovered from COVID-19 and
therefore felt safe leaving their homes. (Then again, the health department
study would have missed people who were self-isolating because they had
symptoms or because they had close contact with people who had COVID-19.)
In South Florida, where the samples analyzed by the CDC were collected from
April 6 through April 19, almost 2 percent tested positive. That is just
one-third the antibody prevalence that University of Miami researchers found
in a random sample of Miami-Dade County residents about a week later. As
with New York City, some of the difference might be due to rising
infections, and some of it might be due to differences in sampling methods.
The CDC study did not use a random sample of the local population, and it
included patients from Broward, Martin, and Palm Beach counties as well as
Miami-Dade. It is also possible that the antibody test used by the
University of Miami researchers, which has relatively low specificity,
generated more false positives than the test used by the CDC.
The CDC put the ratio of infections to confirmed cases in South Florida at
11 to 1, which is the same as the ratio it estimated in Utah, where the
samples were collected from April 20 through May 3, and in western
Washington, where the samples were collected from March 23 through April 1.
Connecticut, where the blood was drawn from April 26 through May 3, had the
lowest ratio of estimated infections to confirmed cases: 6 to 1. Missouri,
where samples were collected from April 20 through April 26, had the highest
ratio: 24 to 1.
TOP ARTICLES
1/5
Writing an Academic Book, Part II: Choosing a
Publisher
What do these findings imply about the infection fatality rate (IFR) in
these places? New York City had recorded 2,580 COVID-19 deaths as of April
1, when the CDC estimates 641,800 residents had been infected, which implies
an IFR of 0.4 percent. (The IFR implied by the state health department's
study, by contrast, was around 0.6 percent.) The COVID-19 death toll in
Connecticut was 2,495 as of May 3, when the CDC estimates the state had
176,700 infections. That implies a much higher IFR: 1.4 percent.
Utah had recorded 57 COVID-19 deaths as of May 3, when the CDC estimates the
state had 47,400 infections, implying an IFR of just 0.1 percent. Missouri's
death toll was 388 as of April 26, when the state had an estimated 161,900
infections. That implies an IFR of about 0.2 percent.
These are just snapshots, and the IFRs in Utah and Missouri may have risen
as the epidemic progressed in those states, especially if people infected in
May were more vulnerable to the disease. But even now, there is a striking
gap between the crude case fatality rates in New York City and Connecticut
(8.4 percent and 9.3 percent, respectively) and the crude CFRs in Utah and
Missouri (0.8 percent and 4.9 percent, respectively). That suggests COVID-19
patients have fared worse in New York City and Connecticut than they have in
Utah and Missouri, for reasons that may include the prevalence of
preexisting medical conditions, the stress that the epidemic put on local
health care systems, and policies regarding high-risk people such as nursing
home residents.
It is plausible that the IFR for COVID-19, as well as the crude CFR, would
vary from one part of the country to another, depending on local conditions.
Based on the CDC's "best estimates" of the death rate among all Americans
who develop COVID-19 symptoms (whether or not they are tested for the virus)
and the percentage of infections that are asymptomatic, the nationwide IFR
is something like 0.26 percent.
Virus testing in the United States has expanded considerably since early
May, which helps explain why the nationwide crude CFR has been falling, from
more than 6 percent on May 16 to less than 5 percent today. As more people
with mild or no symptoms get tested, the denominator includes more low-risk
cases, driving down the apparent death rate. The gap between confirmed cases
and total infections also could shrink as testing is expanded, but that
depends on the pace of new infections, which have been rising at a fast clip
in several states.
In Texas, where newly confirmed cases rose 10-fold between May 26 and June
25 before falling slightly, the share of virus tests that were positive rose
from 4.3 percent on May 26 to 13.2 percent on June 26, which indicates that
expanded testing is not keeping pace with rising infections. It looks like
the gap between confirmed cases and infections is growing in places like
Texas, while it is shrinking in places like New York City, where the test
positivity rate (based on a three-day average) plummeted from 70 percent on
March 30 to 2 percent on June 25.
When the ratio of infections to confirmed cases is high, there is little
hope of containing transmission by identifying and quarantining carriers and
their contacts, even if a state has the capacity to do contact tracing. The
CDC's antibody research "underscores that there are probably a lot of people
infected without knowing it, likely because they have mild or asymptomatic
infection," CDC scientist Fiona Havers told The New York Times. "But those
people could still spread it to others."
The light gray lining of this dark cloud is that newly infected people in
states such as Texas, Florida, Arizona, and California are substantially
younger now than they were earlier in the epidemic, which means the death
rate in those places should be falling. The seven-day average of newly
reported COVID-19 deaths in Texas fell from 58 on April 30, when the
statewide lockdown was lifted, to 20 on June 13. It has since risen to 29
and probably will climb more as recently contracted cases progress. But the
outcome would be far worse if new COVID-19 patients in Texas were older.
Since neither contact tracing nor a vaccine is likely to save high-risk
Texans, the ultimate death toll will depend largely on precautions aimed at
protecting them. Gov. Greg Abbott has responded to the new wave of
infections, which he says is driven largely by young people who have been
getting together for drinks in close proximity, by closing bars. But if
young Texans are increasingly disinclined to follow social distancing rules,
that step may not accomplish much. They can still get together in private,
and their risk of exposure will in any case be higher as they return to
work. Nor can those people, whose own risk of dying from COVID-19 is very
low, necessarily be counted on to avoid contact with Texans who are much
more vulnerable to the disease.
The onus for preventing contact between potential carriers and high-risk
individuals seems to be shifting, fairly or not, from the first group to the
second. Minimizing COVID-19 deaths will require adapting to that reality.
--
This email has been checked for viruses by AVG.
https://www.avg.com
CDC Antibody Studies Confirm Huge Gap Between COVID-19 Infections and Known
Cases
The difference implies that the virus is much less deadly than it looks, but
it also makes contact tracing a daunting challenge.
JACOB SULLUM | 6.28.2020 6:35 PM
COVID-19-antibody-tests-Newscom
(Marijan Murat/DPA/Picture Alliance/Newscom)
Newly published antibody test results from half a dozen parts of the country
confirm that COVID-19 infections in the United States far outnumber
confirmed cases. The ratio of estimated infections to known cases in these
studies, which the U.S. Centers for Disease Control and Prevention (CDC)
reported on Friday, range from 6 to 1 in Connecticut as of early May to 24
to 1 in Missouri as of late April.
These results confirm something we already knew: The COVID-19 infection
fatality rate—deaths as a share of all infections—is much lower than the
crude case fatality rate—deaths as a share of known cases. That is bound to
be true when testing is limited and a virus typically produces mild or no
symptoms. At the same time, the CDC's antibody studies imply that efforts to
control the epidemic through testing, isolation, quarantine, and contact
tracing will not be very effective, since they reach only a small percentage
of virus carriers.
The CDC analyzed blood samples drawn for routine tests unrelated to COVID-19
from patients in New York City, Connecticut, South Florida, Missouri, Utah,
and western Washington state. Although these samples may not be
representative of the general population, they provide a clearer picture of
virus prevalence than screening limited to people who sought virus tests
because they had symptoms consistent with COVID-19 or because they were in
close contact with known carriers.
In New York City, where the samples were drawn from March 23 through April
1, nearly 7 percent tested positive for COVID-19 antibodies, implying that
infections outnumbered reported cases during that period by 12 to 1. The
prevalence estimated by a state-sponsored antibody study conducted from
April 19 to April 28 was three times as high, although the ratio of
estimated infections to known cases (about 11 to 1), was similar. The
difference in estimated prevalence can be at least partly explained by the
spread of the virus between early and late April.
The gap between the two estimates may also be partly due to differences
between the samples used in the studies. The CDC study was based on patients
whose doctors ordered routine blood tests, while the New York State
Department of Health study used blood drawn from randomly selected shoppers.
Infections might have been unusually common among people who ventured out to
stores during the study period, either because they were more likely to
encounter carriers or because they had already recovered from COVID-19 and
therefore felt safe leaving their homes. (Then again, the health department
study would have missed people who were self-isolating because they had
symptoms or because they had close contact with people who had COVID-19.)
In South Florida, where the samples analyzed by the CDC were collected from
April 6 through April 19, almost 2 percent tested positive. That is just
one-third the antibody prevalence that University of Miami researchers found
in a random sample of Miami-Dade County residents about a week later. As
with New York City, some of the difference might be due to rising
infections, and some of it might be due to differences in sampling methods.
The CDC study did not use a random sample of the local population, and it
included patients from Broward, Martin, and Palm Beach counties as well as
Miami-Dade. It is also possible that the antibody test used by the
University of Miami researchers, which has relatively low specificity,
generated more false positives than the test used by the CDC.
The CDC put the ratio of infections to confirmed cases in South Florida at
11 to 1, which is the same as the ratio it estimated in Utah, where the
samples were collected from April 20 through May 3, and in western
Washington, where the samples were collected from March 23 through April 1.
Connecticut, where the blood was drawn from April 26 through May 3, had the
lowest ratio of estimated infections to confirmed cases: 6 to 1. Missouri,
where samples were collected from April 20 through April 26, had the highest
ratio: 24 to 1.
TOP ARTICLES
1/5
Writing an Academic Book, Part II: Choosing a
Publisher
What do these findings imply about the infection fatality rate (IFR) in
these places? New York City had recorded 2,580 COVID-19 deaths as of April
1, when the CDC estimates 641,800 residents had been infected, which implies
an IFR of 0.4 percent. (The IFR implied by the state health department's
study, by contrast, was around 0.6 percent.) The COVID-19 death toll in
Connecticut was 2,495 as of May 3, when the CDC estimates the state had
176,700 infections. That implies a much higher IFR: 1.4 percent.
Utah had recorded 57 COVID-19 deaths as of May 3, when the CDC estimates the
state had 47,400 infections, implying an IFR of just 0.1 percent. Missouri's
death toll was 388 as of April 26, when the state had an estimated 161,900
infections. That implies an IFR of about 0.2 percent.
These are just snapshots, and the IFRs in Utah and Missouri may have risen
as the epidemic progressed in those states, especially if people infected in
May were more vulnerable to the disease. But even now, there is a striking
gap between the crude case fatality rates in New York City and Connecticut
(8.4 percent and 9.3 percent, respectively) and the crude CFRs in Utah and
Missouri (0.8 percent and 4.9 percent, respectively). That suggests COVID-19
patients have fared worse in New York City and Connecticut than they have in
Utah and Missouri, for reasons that may include the prevalence of
preexisting medical conditions, the stress that the epidemic put on local
health care systems, and policies regarding high-risk people such as nursing
home residents.
It is plausible that the IFR for COVID-19, as well as the crude CFR, would
vary from one part of the country to another, depending on local conditions.
Based on the CDC's "best estimates" of the death rate among all Americans
who develop COVID-19 symptoms (whether or not they are tested for the virus)
and the percentage of infections that are asymptomatic, the nationwide IFR
is something like 0.26 percent.
Virus testing in the United States has expanded considerably since early
May, which helps explain why the nationwide crude CFR has been falling, from
more than 6 percent on May 16 to less than 5 percent today. As more people
with mild or no symptoms get tested, the denominator includes more low-risk
cases, driving down the apparent death rate. The gap between confirmed cases
and total infections also could shrink as testing is expanded, but that
depends on the pace of new infections, which have been rising at a fast clip
in several states.
In Texas, where newly confirmed cases rose 10-fold between May 26 and June
25 before falling slightly, the share of virus tests that were positive rose
from 4.3 percent on May 26 to 13.2 percent on June 26, which indicates that
expanded testing is not keeping pace with rising infections. It looks like
the gap between confirmed cases and infections is growing in places like
Texas, while it is shrinking in places like New York City, where the test
positivity rate (based on a three-day average) plummeted from 70 percent on
March 30 to 2 percent on June 25.
When the ratio of infections to confirmed cases is high, there is little
hope of containing transmission by identifying and quarantining carriers and
their contacts, even if a state has the capacity to do contact tracing. The
CDC's antibody research "underscores that there are probably a lot of people
infected without knowing it, likely because they have mild or asymptomatic
infection," CDC scientist Fiona Havers told The New York Times. "But those
people could still spread it to others."
The light gray lining of this dark cloud is that newly infected people in
states such as Texas, Florida, Arizona, and California are substantially
younger now than they were earlier in the epidemic, which means the death
rate in those places should be falling. The seven-day average of newly
reported COVID-19 deaths in Texas fell from 58 on April 30, when the
statewide lockdown was lifted, to 20 on June 13. It has since risen to 29
and probably will climb more as recently contracted cases progress. But the
outcome would be far worse if new COVID-19 patients in Texas were older.
Since neither contact tracing nor a vaccine is likely to save high-risk
Texans, the ultimate death toll will depend largely on precautions aimed at
protecting them. Gov. Greg Abbott has responded to the new wave of
infections, which he says is driven largely by young people who have been
getting together for drinks in close proximity, by closing bars. But if
young Texans are increasingly disinclined to follow social distancing rules,
that step may not accomplish much. They can still get together in private,
and their risk of exposure will in any case be higher as they return to
work. Nor can those people, whose own risk of dying from COVID-19 is very
low, necessarily be counted on to avoid contact with Texans who are much
more vulnerable to the disease.
The onus for preventing contact between potential carriers and high-risk
individuals seems to be shifting, fairly or not, from the first group to the
second. Minimizing COVID-19 deaths will require adapting to that reality.
--
This email has been checked for viruses by AVG.
https://www.avg.com
Andrew B. Chung, MD/PhD
Jun 29, 2020, 10:50:53 AM6/29/20
to
from high-risk individuals (i.e folks with the pre-existing conditions
of obesity,hypertension,diabetes,asthma,emphysema,heart
disease,cigarette-smoking addiction,depression,alcoholism,cancer,etc)
by immediately finding out at any given moment, including while
On-line, who among us are unwittingly contagious (i.e. pre-symptomatic
or asymptomatic) in order to convince them to call their doctor and
self-quarantine per their doctor in hopes of stopping this pandemic
before all our hospitals are overwhelmed.
Indeed, I am wonderfully hungry ( http://bit.ly/RapidTestCOVID-19 )
and hope you, Michael, also have a healthy appetite too.
So how are you ?
...because we mindfully choose to openly care with our heart,
HeartDoc Andrew <><
--
Andrew B. Chung, MD/PhD
Cardiologist with an http://bit.ly/EternalMedicalLicense
2016 & upwards non-partisan candidate for U.S. President:
http://bit.ly/WonderfullyHungryPresident
and author of the 2PD-OMER Approach:
http://bit.ly/HeartDocAndrewCare
which is the only **healthy** cure for the U.S. healthcare crisis
Michael Ejercito
Jun 30, 2020, 9:15:32 AM6/30/20
to
>
> Indeed, I am wonderfully hungry ( http://bit.ly/RapidTestCOVID-19 )
> and hope you, Michael, also have a healthy appetite too.
>
> So how are you ?
>
Michael
Andrew B. Chung, MD/PhD
Jun 30, 2020, 9:40:27 AM6/30/20
to
MichaelE wrote:
>> > The onus for preventing contact between potential carriers and high-risk
>> > individuals seems to be shifting, fairly or not, from the first group to
>> > the second. Minimizing COVID-19 deaths will require adapting to that
>> > reality.
>>
>> We, the people of America, can kindly and mercifully take the onus
>> from high-risk individuals (i.e folks with the pre-existing conditions
>> of obesity,hypertension,diabetes,asthma,emphysema,heart
>> disease,cigarette-smoking addiction,depression,alcoholism,cancer,etc)
>> by immediately finding out at any given moment, including while
>> On-line, who among us are unwittingly contagious (i.e. pre-symptomatic
>> or asymptomatic) in order to convince them to call their doctor and
>> self-quarantine per their doctor in hopes of stopping this pandemic
>> before all our hospitals are overwhelmed.
>
> You got that right!
>
>> Indeed, I am wonderfully hungry ( http://bit.ly/RapidTestCOVID-19 )
>> and hope you, Michael, also have a healthy appetite too.
>>
>> So how are you ?
>
> I am wonderfully hungry!
While wonderfully hungry in the Holy Spirit, Who causes (Deuteronomy
8:3) us to hunger, I note that you, Michael, not only don't have
COVID-19 but are rapture (Luke 17:37) ready and pray (2 Chronicles
7:14) that our Everlasting (Isaiah 9:6) Father in Heaven continues to
give us "much more" (Luke 11:13) Holy Spirit (Galatians 5:22-23) so
that we'd have much more of His Help to always say/write that we're
"wonderfully hungry" in **all** ways including especially caring to
http://bit.ly/ConvinceItForward (John 15:12 as shown by
http://bit.ly/RapidTestCOVID-19 ) with all glory (
http://bit.ly/Psalm117_ ) to GOD (aka HaShem, Elohim, Abba, DEO), in
the name (John 16:23) of LORD Jesus Christ of Nazareth. Amen.
Laus DEO !
Be hungrier, which really is wonderfully healthier especially for
diabetics and other heart disease patients:
http://bit.ly/HeartDocAndrewToutsHunger (Luke 6:21a) with all glory to
GOD, Who causes us to hunger (Deuteronomy 8:3) when He blesses us
right now (Luke 6:21a) thereby removing the http://bit.ly/HeartVAT
from around the heart
> HeartDoc Andrew, in the Holy Spirit, boldly wrote:
>> MichaelE wrote:
>>
>> > http://reason.com/2020/06/28/cdc-antibody-studies-confirm-huge-gap-between-covid-19-infections-and-known-cases/
<snip>
>> MichaelE wrote:
>>
>> > http://reason.com/2020/06/28/cdc-antibody-studies-confirm-huge-gap-between-covid-19-infections-and-known-cases/
>> > The onus for preventing contact between potential carriers and high-risk
>> > individuals seems to be shifting, fairly or not, from the first group to
>> > the second. Minimizing COVID-19 deaths will require adapting to that
>> > reality.
>>
>> We, the people of America, can kindly and mercifully take the onus
>> from high-risk individuals (i.e folks with the pre-existing conditions
>> of obesity,hypertension,diabetes,asthma,emphysema,heart
>> disease,cigarette-smoking addiction,depression,alcoholism,cancer,etc)
>> by immediately finding out at any given moment, including while
>> On-line, who among us are unwittingly contagious (i.e. pre-symptomatic
>> or asymptomatic) in order to convince them to call their doctor and
>> self-quarantine per their doctor in hopes of stopping this pandemic
>> before all our hospitals are overwhelmed.
>
> You got that right!
>
>> Indeed, I am wonderfully hungry ( http://bit.ly/RapidTestCOVID-19 )
>> and hope you, Michael, also have a healthy appetite too.
>>
>> So how are you ?
>
> I am wonderfully hungry!
8:3) us to hunger, I note that you, Michael, not only don't have
COVID-19 but are rapture (Luke 17:37) ready and pray (2 Chronicles
7:14) that our Everlasting (Isaiah 9:6) Father in Heaven continues to
give us "much more" (Luke 11:13) Holy Spirit (Galatians 5:22-23) so
that we'd have much more of His Help to always say/write that we're
"wonderfully hungry" in **all** ways including especially caring to
http://bit.ly/ConvinceItForward (John 15:12 as shown by
http://bit.ly/RapidTestCOVID-19 ) with all glory (
http://bit.ly/Psalm117_ ) to GOD (aka HaShem, Elohim, Abba, DEO), in
the name (John 16:23) of LORD Jesus Christ of Nazareth. Amen.
Laus DEO !
Be hungrier, which really is wonderfully healthier especially for
diabetics and other heart disease patients:
http://bit.ly/HeartDocAndrewToutsHunger (Luke 6:21a) with all glory to
GOD, Who causes us to hunger (Deuteronomy 8:3) when He blesses us
right now (Luke 6:21a) thereby removing the http://bit.ly/HeartVAT
from around the heart
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