News

Los Angeles study backs Stanford researchers' conclusion about high prevalence of COVID-19

USC researchers, who collaborated with Stanford, concluded that about 4% of Los Angeles County residents were infected with virus

Days after Stanford University researchers issued an early draft of a study suggesting that up to 81,000 residents of Santa Clara County had been infected by COVID-19 as of early April, a team at the University of Southern California (USC) released its own serological study that similarly concludes that the disease is far more widespread — and less deadly — than official estimates indicate.

The study by USC and the Los Angeles Department of Public Health concluded that between 2.8% and 4.6% of the adult population in Los Angeles County has an antibody to the virus. This translates to between 221,000 and 442,000 adults — an estimate that is 28 to 55 times higher than the roughly 8,000 confirmed cases that the county had in early April, when the study was conducted.

Led by Neeraj Sood, a USC professor of public policy, the study took blood samples from 863 people who were randomly selected from a list obtained through a marketing firm. According to Sood, 4.1% of those people tested positive for COVID-19. The rate was adjusted to incorporate the statistical margin of error, which was assessed at a lab at Stanford University using blood samples that were positive and negative for COVID-19, according to the university.

The methodology differed slightly from the Stanford study of 3,330 people, which relied on targeted Facebook ads to find participants for its finger-prick exams, which took place on April 3 and 4. The Los Angeles study, which relied on testing at six sites on April 10 and April 11, had fewer participants, though USC had indicated that it is just the first round in a series of antibody-testing studies.

But researchers from Stanford and USC, who collaborated on the studies, found plenty of similarities in their test results. The Stanford study concluded that the number of COVID-19 cases in Santa Clara County is 50 to 80 times higher than the number of confirmed cases. The USC one also found that the number of cases is likely far higher than experts had projected.

What's local journalism worth to you?

Support Mountain View Online for as little as $5/month.

Learn more

Because so many residents with COVID-19 have not been officially tested, both studies conclude that the two counties' mortality rates based on confirmed cases are far higher than mortality rates based on the two studies' estimated numbers of infections.

The Stanford study, led by Assistant Professor Eran Bendavid, concluded that the mortality rate in Santa Clara County is between 0.12% and 0.2%. (In contrast, the county's mortality rate based solely on official cases and deaths as of last Friday, April 17, was 3.9%.)

Sood likewise said at a Monday news conference that because the number of infections in Los Angeles County cases appears to be so much higher than the number of confirmed cases, the actual mortality rate is lower.

"Maybe the good news is that the fatality rate is lower than what we thought it would be," Sood said.

He added, however, that this shouldn't be the only number that the county focuses on. The study's finding that 4% of the county's population has been infected suggests that "we are very early in the epidemic and many more people in Los Angeles County could potentially be infected."

Stay informed

Get daily headlines sent straight to your inbox.

Sign up

"And as the number of infections arise, so will the number of deaths, the number of hospitalizations and the number of ICU admissions," Sood said.

Find comprehensive coverage on the Midpeninsula's response to the new coronavirus by Palo Alto Online, the Mountain View Voice and the Almanac here.

Follow Mountain View Voice Online on Twitter @mvvoice, Facebook and on Instagram @mvvoice for breaking news, local events, photos, videos and more.

Los Angeles study backs Stanford researchers' conclusion about high prevalence of COVID-19

USC researchers, who collaborated with Stanford, concluded that about 4% of Los Angeles County residents were infected with virus

by / Palo Alto Weekly

Uploaded: Tue, Apr 21, 2020, 5:07 pm

Days after Stanford University researchers issued an early draft of a study suggesting that up to 81,000 residents of Santa Clara County had been infected by COVID-19 as of early April, a team at the University of Southern California (USC) released its own serological study that similarly concludes that the disease is far more widespread — and less deadly — than official estimates indicate.

The study by USC and the Los Angeles Department of Public Health concluded that between 2.8% and 4.6% of the adult population in Los Angeles County has an antibody to the virus. This translates to between 221,000 and 442,000 adults — an estimate that is 28 to 55 times higher than the roughly 8,000 confirmed cases that the county had in early April, when the study was conducted.

Led by Neeraj Sood, a USC professor of public policy, the study took blood samples from 863 people who were randomly selected from a list obtained through a marketing firm. According to Sood, 4.1% of those people tested positive for COVID-19. The rate was adjusted to incorporate the statistical margin of error, which was assessed at a lab at Stanford University using blood samples that were positive and negative for COVID-19, according to the university.

The methodology differed slightly from the Stanford study of 3,330 people, which relied on targeted Facebook ads to find participants for its finger-prick exams, which took place on April 3 and 4. The Los Angeles study, which relied on testing at six sites on April 10 and April 11, had fewer participants, though USC had indicated that it is just the first round in a series of antibody-testing studies.

But researchers from Stanford and USC, who collaborated on the studies, found plenty of similarities in their test results. The Stanford study concluded that the number of COVID-19 cases in Santa Clara County is 50 to 80 times higher than the number of confirmed cases. The USC one also found that the number of cases is likely far higher than experts had projected.

Because so many residents with COVID-19 have not been officially tested, both studies conclude that the two counties' mortality rates based on confirmed cases are far higher than mortality rates based on the two studies' estimated numbers of infections.

The Stanford study, led by Assistant Professor Eran Bendavid, concluded that the mortality rate in Santa Clara County is between 0.12% and 0.2%. (In contrast, the county's mortality rate based solely on official cases and deaths as of last Friday, April 17, was 3.9%.)

Sood likewise said at a Monday news conference that because the number of infections in Los Angeles County cases appears to be so much higher than the number of confirmed cases, the actual mortality rate is lower.

"Maybe the good news is that the fatality rate is lower than what we thought it would be," Sood said.

He added, however, that this shouldn't be the only number that the county focuses on. The study's finding that 4% of the county's population has been infected suggests that "we are very early in the epidemic and many more people in Los Angeles County could potentially be infected."

"And as the number of infections arise, so will the number of deaths, the number of hospitalizations and the number of ICU admissions," Sood said.

Find comprehensive coverage on the Midpeninsula's response to the new coronavirus by Palo Alto Online, the Mountain View Voice and the Almanac here.

Comments

R.F.
Cuesta Park
on Apr 22, 2020 at 10:41 am
R.F., Cuesta Park
on Apr 22, 2020 at 10:41 am
18 people like this

If news like this keeps coming out it's going to be really hard to justify draconian stay-at-home orders. How low does the case fatality ratio need to be to restore our constitutional rights?


survivalists
Bailey Park
on Apr 22, 2020 at 1:12 pm
survivalists, Bailey Park
on Apr 22, 2020 at 1:12 pm
10 people like this

Both surveys use the same base Chinese technology. One recruited via facebook, the other thru a marketing firm.

Neither have been peer reviewed.

I love how the vaxxers, survivalists and preppers have spent decades preparing for this pandemic, yet within a couple weeks are crying out: "we have to open our hair salons!"

Man up.

Restaurants and other businesses closed BEFORE the Bay shut down or went statewide. They ain't opening up because ten percent claims they're going to dine out once a week.

We need testing, tracing social distancing.


The Business Man
Castro City
on Apr 22, 2020 at 1:23 pm
The Business Man, Castro City
on Apr 22, 2020 at 1:23 pm
3 people like this

In response to R.F. you said:

“If news like this keeps coming out it's going to be really hard to justify draconian stay-at-home orders.”

What in the reports indicated that the shelter in place is unjustified? You are forgetting the POLI outbreak and that this was used before and is still needed now. You just have to read this:

Actually if you look at our experience with POLIO, that is exactly what was done. You can look up the history from the CDC website found here (Web Link).

Specifically it reported:

“In the late 1940s, polio outbreaks in the U.S. increased in frequency and size, crippling an average of more than 35,000 people each year. Parents were frightened to let their children go outside, especially in the summer when the virus seemed to peak. TRAVEL AND COMMERCE BETWEEN AFFECTED CITIES WERE SOMETIMES RESTRICTED. Public health officials imposed quarantines (used to separate and restrict the movement of well people who may have been exposed to a contagious disease to see if they become ill) on homes and towns where polio cases were diagnosed.”

So this is NOT A SURPRISE on us. It should NOT BE A SURPRISE to you. As far as the number of “death” you determine as ACCEPTABLE by saying:

“And for context, 40k deaths/year is a typical flu season, and we don't shut down everything for the flu.”

However, the shutdowns that occurred during the POLIO outbreak were severe when there was only 15,000 people being paralyzed as reported here:

“Polio was once one of the most feared diseases in the U.S. In the early 1950s, before polio vaccines were available, polio outbreaks caused more than 15,000 cases of paralysis each year. Following introduction of vaccines—specifically, trivalent inactivated poliovirus vaccine (IPV) in 1955 and trivalent oral poliovirus vaccine (OPV) in 1963—the number of polio cases fell rapidly to less than 100 in the 1960s and fewer than 10 in the 1970s.”

Just compare and contrast these situations, Commerce was shut down for just 15,000 paralysis cases, NOT DEATHS, and we on tract to lose more lives than what happened during the ENTIRE Vietnam War which was 58,000. The current recognized undercounted deaths are 46,000+. So you are really insensitive to those deaths, and those that are going to die if you prematurely stop the only control we have at this time. You said:

“How low does the case fatality ratio need to be to restore our constitutional rights?”

The Fifth Amendment of the Constitutional rights are in the order of LIFE, liberty, or property. Thus, the ORDER of precedence in the constitution CLEARLY indicates that LIFE trumps PROPERTY under it. But you are just trying to use misinformation and not even doing any logical inductive or deductive reasoning. The Constitution CLEARLY requires LIFE be the highest PRIORITY, and in many supreme court cases, the courts have held that standard.

And since we do not have SITUATIONAL AWARENESS regarding COVID 19, either everyone has been tested and are being monitored for infection, the complete understanding of whether the virus exposure establishes limited or lifetime protection, nor any real treatment that is proven safe, and reliable or a vaccine that is safe and reliable. Thus the POLIO standard has always been an established viral control, and you are just trying to incite hostility under these circumstances.


Harvey L. Lynch
The Crossings
on Apr 22, 2020 at 2:47 pm
Harvey L. Lynch, The Crossings
on Apr 22, 2020 at 2:47 pm
9 people like this

The Stanford study is on extremely weak ground statistically, as numerous statisticians have pointed out. The basic claim is that the number of people who have been infected is much greater than what was previously thought.

The fundamental problems are that
* The number of tests made is small 3300
* The claimed positive rate is of the order of 2% who have been infected, not who are currently infected.
* A very small amount of leakage of false positives can dominate the result, and the control samples to evaluate the tests are only 30 and 37 for the two possible kinds of identification errors! With such a small control sample it not possible to measure a false positive rate as low as 2%, never mind a factor of 50 to 85 times less as they say has been reported by others.
* The people tested were recruited via Facebook, meaning that the people may self-select for infection.

Reporting on this topic by Lisa Krieger appeared on 21 April 2020 in the San Jose Mercury News, "Do numbers add up? Feud over study".

For the technically inclined their original report is available at Web Link.

Full disclosure: By trade I am an experimental physicist, not a medical doctor, but statistics is a central part of research in both fields.

Harvey L. Lynch


Schmedly
another community
on Apr 22, 2020 at 3:43 pm
Schmedly, another community
on Apr 22, 2020 at 3:43 pm
6 people like this

Regarding the sample size, from what I remember about surveys and statistics, they key point is that you don't need a huge sample size. The important aspect is that the sample be truly random and devoid of selection bias.

So, it comes down to sample selection methodology. This is why broadcasters pay big bucks to Nielson Ratings because they have a proprietary system that very effectively captures a random statistical cross section sample of the US viewer population. It is a relatively small sample, but is quite accurate.

The accuracy of a survey is primarily dependent upon the method of selection, and that I cannot speak to on the study.

If selected properly, you can have a very small sample size that is very accurate. If not selected properly, you can have a very large sample size that is completely inaccurate, e.g. 2016 election polls.


Stop the madness
Bailey Park
on Apr 22, 2020 at 5:00 pm
Stop the madness, Bailey Park
on Apr 22, 2020 at 5:00 pm
8 people like this

The local hospitals are nowhere near “overwhelmed”. In fact they’re practically empty. The original goal was to flatten the curve so as not to exceed the capacity of hospitals to treat the very ill. However rather than slowing the rate of infection it seems they’re attempting to prevent anybody from contracting the virus by imposing more and more stringent restrictions on the public (which will of course prevent herd immunity from occurring but will make big bucks for the pharmaceutical co if they are ever able to develop a vaccine). In terms of reopening the state It now seems that rather than a flat curve Newsom is requiring a downward trend despite knowing that the virulence of this virus, for most people, is not great and our hospital capacity, if needed, is more than adequate.

I’m with R.F. These measures are draconian and they need to end. They have already devastated our economy to a point from which we may never recover. Continued lockdown will put the nails in the coffin.


Christopher Chiang
North Bayshore
on Apr 22, 2020 at 6:19 pm
Christopher Chiang, North Bayshore
on Apr 22, 2020 at 6:19 pm
5 people like this

The people who posted above are correct that there is extra hospital capacity right now in Santa Clara County,
currently around 200 hospitalized patients, which leaves 936 available acute hospital beds, 92 available intensive care unit beds, and 392 ventilators available. Source: Web Link

That said, they are missing one key element the governor is waiting for, added testing capacity. Yes, beds numbers are fine to re-open, but if we don't have the testing ability to ID and trace, we'll be back where we started, and all this sacrifice will be wasted. CA currently has a 16,000 daily test capacity. Governor is aiming at 60,000 daily test capacity for reopening. Source: Web Link

Many Silicon Valley companies are working on testing, maybe your neighbors, if that's you, Godspeed on your innovation and work, so we can all resume, rebuild, as well as properly morn who and what we've lost.


survivalists
Bailey Park
on Apr 22, 2020 at 6:48 pm
survivalists, Bailey Park
on Apr 22, 2020 at 6:48 pm
3 people like this

> 60,000 daily test capacity

Cool. Every California will be tested in 590 days.


Stop the madness
Bailey Park
on Apr 22, 2020 at 7:10 pm
Stop the madness, Bailey Park
on Apr 22, 2020 at 7:10 pm
8 people like this

@christopher chang- why on earth would we want to wait for testing to reopen the economy?? People are dying worldwide as a result of the economic devastation and many more will die, surely more than from CoVid if we continue this senseless lockdown. The UN is predicting famine of biblical proportions in East Africa and South Asia leading to mass starvation within months. The critical factor is hospital capacity. We have that. Open the state back up. The CoVid vulnerable population should stay home and continue self quarantine until this blows over. Everyone else should go back to work.


survivalists
Bailey Park
on Apr 22, 2020 at 7:47 pm
survivalists, Bailey Park
on Apr 22, 2020 at 7:47 pm
9 people like this

> why on earth would we want to wait for testing to reopen the economy??

Try reading any article by an epidemiologist or health professional.

If we open without testing and tracing, the 2nd and 3rd wave of deaths will inundate our healthcare systems and send the economy even lower than now.

Pence promised 4 million tests available in the middle of March - never happened. Trump has claimed for a month that anyone who wants a test can get it - more Trump lies. Trump knew in January that we needed tests. He has failed our economy and thus earned the name: The Trump Bear Market.

A few dozen protesters last weekend (consisting of vaxxers, survivalists and preppers) are not a reason to put the health and economy of 330 million Americans at risk.

Prove us wrong - get five million protesters in the streets like these lovely ladies: Web Link

C'mon. Man Up like the ladies did in the middle of winter, 2017.


The Business Man
Castro City
on Apr 22, 2020 at 8:33 pm
The Business Man, Castro City
on Apr 22, 2020 at 8:33 pm
3 people like this

Survivalists,

JUST FYI.

you said:

> 60,000 daily test capacity

Cool. Every California will be tested in 590 days.

But for tracking purposes you will have to retest everyone for quite a while.

Imagine it takes 1770 days just to try to track the state of California for 3 consecutive tests.

I believe the standard may be as high a 5 consecutive tests.

Oh well, by that time if we go back to normal now, we will have infected all the people in California. So what if tens of thousands die.

SURVIVAL OF THE FITTEST.

Just joking, I do not agree with above.


mvresident2008
Monta Loma
on Apr 23, 2020 at 10:38 am
mvresident2008, Monta Loma
on Apr 23, 2020 at 10:38 am
9 people like this

Testing for the presence of the virus does not really benefit anything, if a person tests as clear they still might get it the next day.
Testing people for the antibodies they produce to combat the virus is beneficial because that means they have had the disease and are now immune and won't contract it again even if they are exposed.
When enough people test positive for antibodies, we have achieved herd immunity, which is the only way out of this pandemic.
The virus gives most folk a mild flu and is effectively the same as a vaccine.


survivalists
Bailey Park
on Apr 23, 2020 at 11:09 am
survivalists, Bailey Park
on Apr 23, 2020 at 11:09 am
15 people like this

> Testing for the presence of the virus does not really benefit anything

Cannot contact-trace w/o testing.

> Testing people for the antibodies they produce to combat the virus is beneficial because that means they have had the disease and are now immune

Yes, and no. There is concern re: reinfection. That will likely be answered once we achieve substantial testing.

> we have achieved herd immunity, which is the only way out of this pandemic.

Highly unlikely we achieve herd immunity w/o vaccines.




Stop the madness
Bailey Park
on Apr 23, 2020 at 4:13 pm
Stop the madness, Bailey Park
on Apr 23, 2020 at 4:13 pm
10 people like this

@mvresident2008 - Herd immunity will never be achieved if we continue to isolate ourselves. Based on this Stanford/USC study it is estimated that 2.5% - 4.5% of the population has been infected. Herd immunity requires about 70% of the population to be immune. With these incredibly strict quarantine restrictions we're not allowing the population that's least vulnerable to death (everybody under 65 years of age) to get the disease and develop the herd immunity. We need to end the lockdown. Waiting for more testing does nothing to protect the vulnerable (they should stay home) and exacerbates the economic devastation we're experiencing. When we enter the 2nd Great Depression will people look back and say, gee, this was no more serious than the flu - maybe we should not have shut the country down.


survivalists
Bailey Park
on Apr 23, 2020 at 5:11 pm
survivalists, Bailey Park
on Apr 23, 2020 at 5:11 pm
12 people like this

> When we enter the 2nd Great Depression

We are already in the Second Republican Great Depression (22M filing for UI in a month? C'mon.)

> this was no more serious than the flu - maybe we should not have shut the country down.

Says no respected health professional or epidemiologist.

Get a grip. Trump earned his stripes by delaying, procrastinating and lying - this is his Trump Bear Market.

We need testing.


Gary
Sylvan Park
on Apr 24, 2020 at 4:03 am
Gary, Sylvan Park
on Apr 24, 2020 at 4:03 am
4 people like this

Which survivors with antibodies are safe to donate blood that can be used to immunize others?


The Business Man
Castro City
on Apr 24, 2020 at 8:59 am
The Business Man, Castro City
on Apr 24, 2020 at 8:59 am
2 people like this

In response to Gary you said:

“Which survivors with antibodies are safe to donate blood that can be used to immunize others?”

You need to understand a few things. When blood plasma with antibodies are uses from a survivor it doesn’t create immunity. If you watch or read, the WHOLE blood is not used in treatment, the blood cells are centrifuged or filters out leaving only the plasma.

The Antibodies are created in the Spleen most of the time via T helper cells that assimilate information from Macrophages that encounter the virus for the first infection. Antibodies do not self-replicate, but are constantly built by the T Helper cells.

In fact during treatment the antibodies are destroyed during the process of attacking the COVID 19. Because they are “markers” for the plasma based immune process

Thus if a person responds fast regarding antibody treatment, they don’t necessarily acquire immunity. Antibody treatment will attack COVID 19 so fast that the body might not achieve the ability to build the antibodies on its own.

I was taught this by a Doctor of Microbiology.

A Vaccine does the process of teaching the body safely he ability to replicate Anti-bodies so that the body has a learned process. This is a significant difference between a “treatment” and a “vaccine”.


Don't miss out on the discussion!
Sign up to be notified of new comments on this topic.

Post a comment

Sorry, but further commenting on this topic has been closed.