CDC citiations

[Oberon245]

I'm having trouble finding CDC citations which support these claims with respect to COVID:

- valid information regarding the body count (is this ONLY measured by death certificates?)

- laboratory studies confirming  asymptomatic individuals spreading  the virus (I'm seeing data analysis and case studies only, apparently)

- accurate case estimates (there appears to be no attempt on the part of the government to gather this data with respect to measuring asymptomatic cases)

If someone has data to contribute, it would be much appreciated, and thanks in advance

[studiot]

16 minutes ago, Oberon245 said:

I'm having trouble finding CDC citations which support these claims with respect to COVID:

- valid information regarding the body count (is this ONLY measured by death certificates?)

- laboratory studies confirming  asymptomatic individuals spreading  the virus (I'm seeing data analysis and case studies only, apparently)

- accurate case estimates (there appears to be no attempt on the part of the government to gather this data with respect to measuring asymptomatic cases)

If someone has data to contribute, it would be much appreciated, and thanks in advance

Which government would this be ?

 

We in the UK understand that different countries are measuring these figures differently.
Even the UK government changed its method of reporting part way through.

Further I'm sure there will be revisions after the event as mistakes will also have been made.

[Oberon245]

How do you handle these things in the UK? The more detail you could provide, the better. Specifically peer-reviewed research the UK government cites to support it's policies. Thank you for replying BTW.

[CharonY]

1 hour ago, Oberon245 said:

I'm having trouble finding CDC citations which support these claims with respect to COVID:

- valid information regarding the body count (is this ONLY measured by death certificates?)

- laboratory studies confirming  asymptomatic individuals spreading  the virus (I'm seeing data analysis and case studies only, apparently)

- accurate case estimates (there appears to be no attempt on the part of the government to gather this data with respect to measuring asymptomatic cases)

If someone has data to contribute, it would be much appreciated, and thanks in advance

As Studiot pointed out, different countries have different reporting systems. The US specifically was potentially hobbled by the last administration. Normally you will find details on their respective websites how they do it. However, the data is generally submitted on the local level, e.g. coded by a hospital and then may go through local health authorities or even submitted simultaneously to local and federal reporting systems. 

As example here are reporting instructions from the US-CDC: https://www.cdc.gov/coronavirus/2019-ncov/downloads/php/COVID19-CSV-Case-Reporting-Instructions.pdf

With regard to asymptomatic spread, there is of course no way you can test that in laboratory directly as it involved to actually make someone sick. Rather, folks will depend on retrospective analyses or other measures, including antibody and wastewater testing. However, tests of folks who are asymptomatic but turned out to be positive  found that even without symptoms, the viral titer can be fairly high, which makes spread very likely. Likewise, asymptomatic spread is also the best explanation for high levels of community spread, where infected folks could not be linked to positive cases.

Also you need to define "accurate case estimates". The most accurate number are of course people tested positive, which forms the baseline. If you want to figure out how many may be underreported, that requires additional research. As the pandemic is still ongoing, the estimates will continue to change so I am not sure to what accuracy would refer to here (a specific timeframe, for example?).

 

[Oberon245]

" no way you can test that in laboratory directly" - I'm sorry but why is that exactly? There have been many studies which measured symptomatic spread of respiratory viruses, some of which have been cited to support asymptomatic spread, although that does not appear to be a valid comparison.

 

"The most accurate number are of course people tested positive, which forms the baseline." - how can this be in any way accurate if no general testing protocol has been established? The CDC said on their website that "not all individuals need to be tested" which is very confusing given that  asymptomatic individuals are allegedly spreading the virus and b) there can be no accurate IFR or CFR statement or estimate without that data.

 

specific timeframe: 2020

Charon, you describe yourself as a "biology expert."  Can you clarify what this means? I don't mean to question your credentials, its just that I thought biology was too vast a field to be amenable to general expertise...

also did the last administration really craft the CDC policies with respect to C-19? Because this is where the failure appears to lie....

[CharonY]

1 hour ago, Oberon245 said:

" no way you can test that in laboratory directly" - I'm sorry but why is that exactly? There have been many studies which measured symptomatic spread of respiratory viruses, some of which have been cited to support asymptomatic spread, although that does not appear to be a valid comparison.

 

A direct test would involve to deliberate infect a person. For some diseases it is possible to have them approved as the risks are well known and can be controlled. SARS-CoV-2 has too many surprises at this point, including causing blood clots and causing neurological symptoms. As such it would be highly unethical to initiate such studies. There are also no good proxies as other coronavirus have quite different infection properties. However, what has been done is measure the titer of infected folks (symptomatic and asymptomatic). There would be no reason to assume that viral particles produced by an asymptomatic patient would be any less infectious than from a symptomatic one.

1 hour ago, Oberon245 said:

"The most accurate number are of course people tested positive, which forms the baseline." - how can this be in any way accurate if no general testing protocol has been established? The CDC said on their website that "not all individuals need to be tested" which is very confusing given that  asymptomatic individuals are allegedly spreading the virus and b) there can be no accurate IFR or CFR statement or estimate without that data.

Not sure what you mean. Testing protocols are well established. And the number of positively tested folks are clearly our lower limit of estimates. I.e. we know that at least that many folks were infected. To figure out the likely values beyond that requires additional research. These include indirect measures, environmental measures or antibody testing. There are studies out there which, given the time frame obviously cannot cover the whole of 2020 and likely will take a bit longer to provide us with estimates.

1 hour ago, Oberon245 said:

Charon, you describe yourself as a "biology expert."  Can you clarify what this means? I don't mean to question your credentials, its just that I thought biology was too vast a field to be amenable to general expertise...

It is not something that I describe myself, rather if folks on this forum have demonstrated expertise in a certain field, they may be given such broad labels, if they agree to it  (e.g. we got physics experts, but their specialty is of course a sub-field). But my main expertise is in cellular and microbial systems and associated analytics. From memory I think every local expert had advanced degrees in their field. But I do not think that we have that many left. But for the most part is just a whimsy thing to have, as you will note by the various free-form labels many of our older members have.

1 hour ago, Oberon245 said:

also did the last administration really craft the CDC policies with respect to C-19? Because this is where the failure appears to lie....

It is less a failure of policy, but rather a failure to adhere to them. After H1N1 the Obama administration has created a pandemic task force, to specifically deal with pandemics and allow tight coordination of the CDC with local health authorities. However, the task force was basically dismantled and folks were put in place who basically downplayed the disease. Reportedly there was a lot of friction between what the CDC wanted to do and what the Trump administration wanted and it included changes in how data was collected and/or presented, limiting how the CDC could communicate with the public. Specifically to your question of asymptomatic testing, there was a report where a senior CDC official told the press that there was pressure from the administration to stop recommending testing if one has symptoms in order to keep the infections numbers lower.

Likewise, at one point the administration decided to move the responsibility to collect data from the CDC and hired a private contractor, resulting in the resignation of data officers of the CDC. In summary it does appear that much of it was preventing the CDC from doing their job in order to control the narrative. That is not to say that a fully-led CDC response would not have had issue, but we know that with all the politicking around the issue, the USA has suffered the most (validated) COVID-19 related deaths and serves as an example what happens if one does not take measures.

[studiot]

1 hour ago, CharonY said:

 

With regard to asymptomatic spread, there is of course no way you can test that in laboratory directly as it involved to actually make someone sick.

Actually they are just starting this type of trial in the UK. direct infection of selected volunteers.
This was announced a few days ago on the BBC.
Sorry I don't have more details at the moment.

3 hours ago, Oberon245 said:

valid information regarding the body count (is this ONLY measured by death certificates?)

Since about the first 2 months the UK government has been announcing (daily and cumulative) totals of all those who
1) Had a positive covid test within 28 days before death
2) Has covid specifically stated on the death certificate.

 

3 hours ago, Oberon245 said:

accurate case estimates (there appears to be no attempt on the part of the government to gather this data with respect to measuring asymptomatic cases)

The government announces confirmed cases only in the totals.

3 hours ago, Oberon245 said:

laboratory studies confirming  asymptomatic individuals spreading  the virus (I'm seeing data analysis and case studies only, apparently)

London University has carried out mass testing within the general population (my family has participated in this) over a 3 month period to assess these figures.
This was done by distributing home self test kits and collecting the results.
Those who were revealed to be asymptomatic on thesewere sent for further tests /advised to self isolate.

 

Further data is being gathered on so callled excess deaths.
This is the increased number of deaths experienced over the long term average for the time of year.
This is larger than just the covid deaths since other increases have also occurred and attempts have been made to allow for this.

[CharonY]

Just now, studiot said:

Actually they are just starting this type of trial in the UK. direct infection of selected volunteers.
This was announced a few days ago on the BBC.
Sorry I don't have more details at the moment.

I stand corrected then, but I admit it does surprise me. There were a couple of discussion on that matter and at least personally I do not think that we can control the risks well enough to pass it through ethics review. But apparently others see it differently. Thanks for letting me know, btw, I found a related article, apparently they got approval to test 90 volunteers to check infectious dosages. 

 

3 minutes ago, studiot said:

Further data is being gathered on so callled excess deaths.
This is the increased number of deaths experienced over the long term average for the time of year.
This is larger than just the covid deaths since other increases have also occurred and attempts have been made to allow for this.

Absolutely. I haven't seen calculations covering the whole of 2020 and while the lack of a flu season curbs things a little bit in some areas, but even in the middle of last year, the excess deaths have pushed overall mortality statistics a fair bit.

[Oberon245]

Charon, you don't understand this statement?

"The CDC said on their website that "not all individuals need to be tested" which is very confusing given that  asymptomatic individuals are allegedly spreading the virus and b) there can be no accurate IFR or CFR statement or estimate without that data."

To be clear, there can be NO ACCURATE ESTIMATE OF CASES without population-wide, consistent testing  for a virus which presents asymptomatically at least 45% of the time. Basing IFR on SYMPTOMATIC cases and hospitalizations presents a gross distortion of the statistic.  I would think this is academic....

[swansont]

8 minutes ago, Oberon245 said:

Charon, you don't understand this statement?

"The CDC said on their website that "not all individuals need to be tested" which is very confusing given that  asymptomatic individuals are allegedly spreading the virus and b) there can be no accurate IFR or CFR statement or estimate without that data."

Where does the CDC say this? Not a lot of Google hits.

One is from http://www.co.iroquois.il.us/wp-content/uploads/2020/03/Iroquois-County-COVID-19-Preparedness-and-Response_PR_032520.pdf which is from last March, when testing was severely constrained, and was prioritized for people with symptoms

2 hours ago, Oberon245 said:

Charon, you describe yourself as a "biology expert."  Can you clarify what this means? 

Resident expert titles are not self-bestowed. It’s a designation made by the staff, based on demonstrated ability (and possibly credentials) that the person possesses expertise in the field.

[CharonY]

1 hour ago, Oberon245 said:

"The CDC said on their website that "not all individuals need to be tested" which is very confusing given that  asymptomatic individuals are allegedly spreading the virus and b) there can be no accurate IFR or CFR statement or estimate without that data."

To be clear, there can be NO ACCURATE ESTIMATE OF CASES without population-wide, consistent testing  for a virus which presents asymptomatically at least 45% of the time. 

I think you misunderstanding something or you might be a bit unclear what you want to achieve. There is no way to have 100% accurate patient data virtually with any disease outbreak as you would have to test everyone and keep testing until the outbreak is over (just because you test negative now does not mean you will be negative tomotrow, or the day after). Except for very small populations this is not feasible, the CDC recommendation notwithstanding (I am not even sure why you bring that one up, it does little to address the overall challenges in accurate disease monitoring).

What folks have always done is to use secondary measures on top of the known cases to estimate infection rates, as I mentioned above. This is why we do have general ranges of estimates of things like the flu season. I do not see why COVID-19 should be different (except that we have done more tests). The issue is with you bringing up "accurate". All disease estimates have an error. If your criterion is an error of 0% then it is likely not obtainable except in very small precisely defined populations. 

1 hour ago, Oberon245 said:

Basing IFR on SYMPTOMATIC cases and hospitalizations presents a gross distortion of the statistic.

Again, I mentioned that IFR and other measures of mortality have very specific (and somewhat limited) uses. If you want to compare diseases, for example then it depends on how you measure them. For most diseases reporting is done on symptomatic cases as we have no or little data on folks that may have been positive but do not have sufficient symptoms to seek a physician. And even then, often they are sent back with some cough and fever medicine rather than a test. Again, it is not clear to me what precisely you seek to compare. The only important bit is that an apple-to-apple comparison is made.

Folks have done serological investigations into defined populations to estimated IFR for SARS-CoV-2 to be around 0.45-1%, depending on the study and with estimates of ca. 20% asymptomatic cases. Of course, that will also depend on the age distribution.

But again, in isolation I am not sure what that would tell us other that if we let everyone getting infected would be lose up to 1% of a given population to the disease (ignoring age gradients). If the idea is to figure out whether the disease has more or less impact than others, I think other metrics (as others have pointed out) are more interesting.

 

[studiot]

Update

In a BBC interview this morning with the LU professor conducting some of the studies I mentioned before, REACT and REACT-2, it was revealed that they ahve now gained enough information to start separating the effects of no vaccination, a single shot of vaccination and a double shot of vaccination,  and the difference between the effects of vaccination on those who have or already had covid and those who did not.

 

[CharonY]

1 hour ago, studiot said:

Update

In a BBC interview this morning with the LU professor conducting some of the studies I mentioned before, REACT and REACT-2, it was revealed that they ahve now gained enough information to start separating the effects of no vaccination, a single shot of vaccination and a double shot of vaccination,  and the difference between the effects of vaccination on those who have or already had covid and those who did not.

 

An interesting bit is that a single dose of either mRNA vaccine in patients who had an infection longer than 6 months ago resulted in a rapid increase of anti-spike protein IgG similar to two dosages of vaccinations.

Closer on-topic, it seems that the question is fundamentally whether there truly is asymptomatic transmission. There are also apparently some things that are potentially unclear. For starters, the rate of asymptomatic cases have been revised down to 17-20% (UK and US data mostly). Initial reports overestimated true asymptomatic carriers as quite a few developed symptoms later in the disease.

True asymptomatic carriers have a shorter time-frame in which they are positive (most were tested negative within 14 days) limiting the time-frame in which they could infect other persons. 

However, unless there is sufficient follow-up it is difficult to distinguish pre- and asymptomatic carriers and depending on the data, they may be classified as a single group. I.e. folks that are positive, might infect folks, but show no symptoms at time of testing.

Why do folks think that asymptomatic or pre-symptomatic carriers might be infectious? The reason is that in all cases significant viral loads are detected. Among pre-symptomatic carriers the level is highest just before onset of symptoms (in other respiratory diseases the titer tends to be higher during symptom onsets). I.e. there is good reason to believe that folks can transmit even if they do not show symptoms (yet).

Viral load is a decent indicator of potential risk and while there is a high variance among patients (regardless of symptoms or not) larger patient pools indicate that even truly asymptomatic carriers can carry high loads (at least as high as mild carriers).

The only real counter-argument so far is that most analyses are based on genetic material and few folks are actually doing cultures to check whether the virus actually infects a cell culture. 

The other side of the argument is epidemiological in nature, where there is a big discrepancy between (known) active cases and spread patterns. It could be caused by folks with no or mild symptoms that do not get tested. Other evidence are gathered by isolating families in which spread was detected but the carrier did not show symptoms.

As a whole, it is more likely than not that asymptomatic spread adds to the pandemic, though uncertainty exists about relative contribution. Obviously it will depend on the population (e.g. in older populations symptomatic cases will likely be much higher, whereas in younger milder cases may be dominant). Also asymptomatic cases have a shorter window of infection, so in well-isolated communities they may be not that relevant.

However, as there is no means to test everyone all the time, from a health policy perspective the only effective measure is to isolate and distance, regardless of detected symptoms (again, based on known viral kinetics).