New study investigates California's possible herd immunity to COVID-19

KSBW Action News ^ | 4/8/2020 | Caitlin Conrad

[Zenyatta]

Researchers at Stanford Medicine are working to find out what proportion of Californians have already had COVID-19. The new study could help policymakers make more informed decisions during the coronavirus pandemic.

The team tested 3,200 people at three Bay Area locations on Saturday using an antibody test for COVID-19 and expect to release results in the coming weeks. The data could help to prove COVID-19 arrived undetected in California much earlier than previously thought.

The hypothesis that COVID-19 first started spreading in California in the fall of 2019 is one explanation for the state's lower than expected case numbers.

[RayChuang88]

Now, I REALLY wonder that strange three-day cold I got in mid-December was actually a very mild case of COVID-19.... 🤔🤧

[ARW]

Nov/Dec is beginning of flu season so without testing at the time there’s no way to be sure. Still, it makes sense the entire west coast went COVID at the end of 2019...which would mean it didn’t fulfill the hype and wipe out a million people absent social distancing.

[Mustangman]

This makes total sense to me.

I live in the Bay Area. My son had the worst flu back in January and my sister’s family all had the worst cough around christmas time so I avoided her house....because I wanted no part of that.

Everyone in the fam said they had never been that sick before.... but no one was ever worried about anything. It was a winter cold/flu. Or was it?

If the virus got started in mid November, there is just no way it didnt get into the Bay Area in early December if not earlier.

Obviously the science needs to play out, but I’m inclined to believe this article.... based on my experience. Plus, Why don’t we have more cases? This is the freaking Bay Area...an international hot spot. What else but Herd immunity explains our relative low ‘new infection’ numbers?

[PMAS]

Plus they starting closing down subway lines, packing in more people on the lines that were still running

[Dawggie]

“I have no doubt that this thing was floating around the SF Bay Area and Los Angeles much earlier.”

Yes, there was a strange illness, almost like a flu, but also different. Lasted 3 weeks. Had my son on the nebulizer every 4 hours for a 3 days. I got it too, weird flu if that is what it was.

I would like to think we have had the coronacrop already.

[Oldexpat]

We had a similar flu going around in our Tucson retirement community in dec and jan. Persistent dry cough, ache all over and sore throat. Many had it. Two weeks or more.

[SoCal Pubbie]

I started a “cold” in the third week of January that lasted a month. Lots of dry coughing. I was told at the time that it was going around. No other symptoms but I wonder.

[Vendome]

What if the CDC were only reporting the CCP-19 exact numbers(supposedly) of those "They Tested" who are infected?

See, infected might mean this virus is just on your skin or you may be asymptomatic.

Would they be lying? Well, no. Not in a literaly sense but, if you look at how they determine how many sick and dead people get, had or died from influenza you might think "These guys must scientists!"

Well, they are epidemiologists and a bit like biologists in their methodology.

This going to be over simplified

That is: They make determinations about populations of whatever a thing is by a technique known as "sampling"

For instance, if a biologist counts 100 bears living in a 200-square mile area, they could could predict that there are 1000 bears living in 2000 square miles. This is a simple ratio.

Epidemioligists do the same thing. They take a known quantity and extrapolate that to another known larger quantity.

In fact, look here: https://www.sccgov.org/sites/phd/DiseaseInformation/novel-coronavirus/Pages/dashboard.aspx

That is Santa Clara county. They tell you

11782 tests were completed of those 1285 were infected resulting in 43 deaths

Santa Clara County has a population of 1.2 million so if you can use numbers the way an epidemiologist would and using "simple sample method"

Does that mean 1,200,000 / 11782 = 130,877 people are infected (estimated/guess)?

and the death rate in percentage of those infected with CCP-19 is .03%

???

 

 

2019-2020 U.S. Flu Season: Preliminary Burden Estimates

 

 

CDC estimates* that, from October 1, 2019, through March 28, 2020, there have been:

39,000,000 – 55,000,000
flu illnesses

18,000,000 – 26,000,000
flu medical visits

400,000 – 730,000
flu hospitalizations

24,000 – 63,000
flu deaths

*Because influenza surveillance does not capture all cases of flu that occur in the U.S., CDC provides these estimated ranges to better reflect the larger burden of influenza. These estimates are calculated based on CDC’s weekly influenza surveillance data and are preliminary.

**Influenza testing across the United States may be higher than normal at this time of year because of the COVID-19 pandemic. These estimates may partly reflect increases in testing in recent weeks and may be adjusted downward once the season is complete and final data for the 2019/20 season are available.

On This Page

• Limitations
• Frequently Asked Questions

 

This web page provides weekly, preliminary estimates of the cumulative in-season numbers of flu illnesses, medical visits, hospitalizations, and deaths in the United States. CDC does not know the exact number of people who have been sick and affected by influenza because influenza is not a reportable disease in most areas of the U.S. However, CDC has estimated the burden of flu since 2010 using a mathematical model that is based on data collected through the U.S. Influenza Surveillance System, a network that covers approximately 8.5% of the U.S. population (~27 million people).

Limitations

The estimates of the cumulative burden of seasonal influenza are subject to several limitations.

First, the cumulative rate of laboratory-confirmed influenza-associated hospitalizations reported during the season may be an under-estimate of the rate at the end of the season because of identification and reporting delays.

Second, rates of laboratory-confirmed influenza-associated hospitalizations were adjusted for the frequency of influenza testing and the sensitivity of influenza diagnostic assays. However, data on testing practices during the 2019-2020 season are not available in real-time. CDC used data on testing practices from the past influenza seasons as a proxy. Burden estimates will be updated at a later date when data on contemporary testing practices become available.

Third, estimates of influenza-associated illness and medical visits are based on data from prior seasons, which may not be accurate if the seriousness of illness or patterns of care-seeking have changed.

Frequently Asked Questions

What does the cumulative burden of influenza for the 2019-2020 season mean?

The cumulative burden of influenza is an estimate of the number of people who have been sick, seen a healthcare provider, been hospitalized, or died as a result of influenza since October 01, 2018. CDC does not know the exact number of people who have been sick and affected by influenza because influenza is not a reportable disease in most areas of the United States. However, these numbers are estimated using a mathematical model, based on observed rates of laboratory-confirmed influenza-associated hospitalizations.

How does CDC estimate the cumulative burden of seasonal influenza?

Preliminary estimates of the cumulative burden of seasonal influenza during the 2019-2020 season in the United States are based on crude rates of laboratory-confirmed influenza-associated hospitalizations, reported through the Influenza Hospitalization Surveillance Network (FluSurv-NET), which were adjusted for the frequency of influenza testing during recent prior seasons and the sensitivity of influenza diagnostic assays. Rates of hospitalization were then multiplied by previously estimated ratio of hospitalizations to symptomatic illnesses, and frequency of seeking medical care to calculate symptomatic illnesses, medical visits, and deaths associated with seasonal influenza, respectively.

Why does the estimate of cumulative burden change each week?

The estimates of cumulative burden of seasonal influenza are considered preliminary and may change each week as new laboratory-confirmed influenza-associated hospitalizations are reported to CDC. New reports include both new admissions that have occurred during the reporting week and also patients admitted in previous weeks that have been newly reported to CDC.

How does the number of flu hospitalizations estimated so far this season compare with previous end-of-season hospitalization estimates?

The number of hospitalizations estimated so far this season is lower than end-of-season total hospitalization estimates for any season since CDC began making these estimates. This table also summarizes all estimated influenza disease burden, by season, in U.S. from 2010-11 through 2017-18.

[TexasGator]

Some differences:

California slowed inbounds earlier than New York

New York City bigger international hub.

More from Italy into NYC

Chinese New Year / De Blasio promotions

Healthier people more likely not to be included in database of infected.

Winter factors common to the flu worse in NY.

[CaliGangsta]

Despite getting a flu shot, I had the worst “flu” of my life in early / mid February. In addition to the normal fever / chills, there were two things about this virus that were particularly severe - First it gave me the worst sore throat of my life, it hurt greatly to talk, hurt to breathe even. Second the back pain was extreme, no matter what I did and how I positioned myself, I was in extreme pain. After about 12 hours of trying to make it through and nearly crying from the pain near the end, I decided to medicate myself with OTC drugs like Tylenol, NyQuil, Ibuprofen. I was basically taking max dose of all three to the limit allowed on the label for several days.

I thought I was better after a few days and even went to work for a few days. Then a few days later, I picked up the “flu” again! This time it was much less severe, basically 24 hours and done.

I believe I (and many others in Santa Clara County) had the disease and recovered from it. Who knows how many had it and didn’t notice due to no symptoms. We didn’t quarantine, we didn’t demand that the entire US economy shutdown, we didn’t even notice because the effects were not worse than a severe flu.

[PGR88]

They will need to millions of antibody tests to get an accurate picture.

Does that capability even exist?

[PGR88]

I have no doubt that this thing was floating around the SF Bay Area and Los Angeles much earlier.

I believe the same. Do we really believe China has so easily identified “patient zero,” conveniently in the Wuhan Wet Market, in late November??

Do we also believe that Shanghai, China’s largest city of 25 million (!) has only had a total of 536 cases, and only 6 deaths?

America’s politicians have been flying blind on this disease since the start, and the only map anyone had was half-truths and outright lies issued by China.

[walkingdead]

I believe this to be the case. The “flu” ran through at least northern CA late last year, into early this year. People even commented on how a nasty bug was going around, but no one was concerned. This happens during the winter, and sometimes they are worse than others.

Those cases could have very well been the ‘rona, and if so, our heard immunity numbers are probably pretty good.

Bummer is shelter in place may have interfered with critical mass on heard immunity.

[arthurus]

I believe that my county received the CCP virus in two waves, one in February when there were several arrivals from China at the airport and everybody seemed to have something flulike but more a discomfort than a dread disease. Then again a wave toward the end of March from which we have the announcements of numbers (under 30)and the numbers are not going up exponentially but by ones and twos.Few people are getting sick at all. Our two biggest employers are still open and working at full capacity, a paper mill and a shipyard with together perhaps 3000 employees. Social distancing is a phrase but the lads all work on top of each other in the shipyard at least.

[glasseye]

Something here stinks.
From the article: “ Technicians use a finger prick to draw blood for the test and it can tell within minutes if a person developed antibodies to COVID-19.”
So they had the data last Saturday and still no ‘results’ for the public.
The ‘spin’ has been time consuming to formulate?
Something here stinks...

[redfreedom]

I find this interesting. Let’s assume this did hit CA a while back, that many contracted this China Flu, had no idea what it was, got over it, and moved on in a similar fashion we all do with the common flu. If that is the case, then there could not have been more deaths per capita than the common flu.

And if this is true, it was all done without shutting down the economy, having people stay at home, closing businesses, the MSM creating panic and blaming it all on Trump.

And if this is true, there’s no damn reason for this stay at home crap to continue!

[17th Miss Regt]

If they can show that it arrived in California in fall of 2019 then they will use it as a stick to beat Trump with over not acting several months earlier than he did.

It's what they do.

[j.havenfarm]

Ditto to all. My “flu” around Washington’s Birthday here in Placer County was unlike any flu I have ever had, and much more like the SARS that almost killed me 22 years ago. Numerous friends and relatives with similar reports. These stories are legion here in California. It has to be the explanation that we had a first wave; nothing else makes sense.
Bearing in mind the 80% who have no or only mild symptoms, I’ve very well could have hit the herd immunity threshold one of the other commenters cited.

[PLOM...NOT!]

Could CA have a lower infection rate because the average temperature is much higher than NY for this time of year?

[RayChuang88]

Trump should "virtually" bop the head of any Democratic politician that suggests this. The thing was that from the beginning of December to the end of February, it's the worst part of the cold/flu season. Because COVID-19 has symptoms often mistaken for a stronger common cold or flu infection, you really wonder the supposedly bad cold/flu season this past winter was heavily COVID-19 but the epidemiologists didn't really identify it until mid-January 2020.