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Youyang Gu
@youyanggu
Data Scientist. Creator of covid19-projections.com and yolostocks.live. Presenter of unbiased takes. Realist.
@MIT
'15.
New York, NYyouyanggu.comJoined February 2009
657 Following
76.5K Followers

Youyang Gu’s Tweets

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Youyang Gu
@youyanggu
It's popular to use the US as a punching bag these days, but I can't think of many other countries where the work of an untrained 27-year-old immigrant can garner the attention & respect of researchers and public alike. America isn't perfect, but I'm grateful to call it my home.
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Youyang Gu
@youyanggu
Global excess deaths in 2020-2021 is almost 3x higher than reported #COVID19 deaths. Great work by
@WHO
&
@UNDESA
to get this out. It's probably the most comprehensive estimates to date.
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World Health Organization (WHO)
@WHO
The total number of deaths associated with #COVID19 worldwide from 2020-2021 may be closer to 14.9 million: New estimates by WHO & @UNDESA. That’s 9.5 million more deaths than reported bit.ly/38SJIpM #HealthData
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Youyang Gu
@youyanggu
"In a recent exercise Youyang Gu, a data scientist, ran multiple versions of a model that seeks to find correlations between 41 variables & American state-level deaths from covid-19... [He finds] inequality has the biggest effect." Here is that exercise:
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Youyang Gu
@youyanggu
I believe income inequality is the single best predictor of total Covid deaths in the US. Not income, but income *inequality*. The R^2 is surprisingly high: 0.35. Thanks to @joe_sill, I was able to look at over 40 different variables, and expands on my analysis from last month.
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Youyang Gu
@youyanggu
Strong claims like "universal masking being one of the most effective and efficient strategies for preventing SARS-CoV-2 transmission in schools" require strong evidence. Unfortunately, the evidence presented by the authors of this study fails to support that claim.
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Youyang Gu
@youyanggu
This is another good example of the double standard in science and academia when it comes to studying pandemic interventions:
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Youyang Gu
@youyanggu
Replying to @youyanggu and @CT_Bergstrom
When people use mere correlation to suggest that restrictions are effective, you see scientists nod their heads. But when people use correlation to suggest restrictions aren't effective, scientists immediately scream "wrong". I just don't think that's very scientific, IMHO.
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Youyang Gu
@youyanggu
There's a
@nytopinion
article regarding universal masking in schools being shared by many, including some prominent experts. But the study never had a control group, so it's scientifically inaccurate to make any conclusions. Here's a good critique of that piece:
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David Zweig
@davidzweig
THREAD I corresponded with the authors of the Duke study behind this opinion piece weeks ago... nytimes.com/2021/08/10/opi
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Youyang Gu
@youyanggu
Not only did he help lead the first large-scale sequencing project of the SARS-CoV-2 genome, he also truly understands both sides of the debate, better than myself. Please consider giving him a follow!
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Youyang Gu
@youyanggu
Great interview with Prof
@BallouxFrancois
about Covid & scientific discourse. We need more pragmatic researchers like him. "As a scientist, you need to be open to surprise and to let your priors be updated by new data. Being dogmatic is problematic."
theguardian.com
Prof Francois Balloux: ‘The pandemic has created a market for gloom and doom’
The UCL scientist and ‘militant corona centrist’ on the risk of new variants, psychosomatic long Covid and when he expects the crisis to end
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Youyang Gu
@youyanggu
Any consequential policy must properly address the long-term consequences and factor in the risk/benefit tradeoffs. Unfortunately, too many times, our policies have ended up disproportionally benefitting the wealthy and further widening the inequality gap.
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Youyang Gu
@youyanggu
"Districts that went strictly remote experienced 42 percent more decline [in kindergarten enrollment]. City schools, which serve disproportionate numbers of low-income students of color, were the most likely to shutter classrooms for extended periods."
nytimes.com
The Kindergarten Exodus (Published 2021)
As the pandemic took hold, more than 1 million children did not enroll in local schools. Many of them were the most vulnerable: 5-year-olds in low-income neighborhoods.
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Youyang Gu
@youyanggu
As I didn't realize this thread would blow up, some additional clarifications: 1) My claim is based on my past analysis on the effectiveness of restrictions in the US: twitter.com/youyanggu/stat 2) Here is the original source which my Tweet was based from: businessinsider.com/uk-lifting-res
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Youyang Gu
@youyanggu
Is containing COVID-19 a requirement for preserving the economy? My analysis suggests: probably not. In the US, there is no correlation between Covid deaths & changes in unemployment rates. However, blue states are much more likely to have higher increases in unemployment. 🧵
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Youyang Gu
@youyanggu
To clarify, I am not anti-lockdown. If lockdown/restrictions work and the benefits are worth the trade-offs, then I'm all for it. I just haven't seen solid evidence of causal effectiveness & a thorough discussion of the trade-offs. I'm anti-bad science.
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Youyang Gu
@youyanggu
Replying to @youyanggu and @CT_Bergstrom
When people use mere correlation to suggest that restrictions are effective, you see scientists nod their heads. But when people use correlation to suggest restrictions aren't effective, scientists immediately scream "wrong". I just don't think that's very scientific, IMHO.
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Youyang Gu
@youyanggu
While cases in the UK reached similar levels as the Winter wave, deaths are less than 10% of the Winter wave. Unlike the fuzzy evidence on the effectiveness of restrictions, there is overwhelming evidence that vaccines are effective at reducing severe illness/death.
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Youyang Gu
@youyanggu
Many bad papers looked at these curves in 2020 & concluded that more restrictions is followed by a decline in cases, when the decline would've happened regardless. If we apply the same flawed logic here, one can say that the lifting of restrictions is followed by fewer cases.
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Youyang Gu
@youyanggu
People were worried cases would spike further when the UK lifted almost all remaining restrictions in July. The opposite happened. We must acknowledge that restrictions aren't all that effective in Western countries. (Except Australia, who just entered their 6th lockdown)
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Youyang Gu
@youyanggu
One leaked CDC memo & headlines went from "99% of Covid cases are among the unvaccinated" to "majority of cases are among the fully vaccinated". In reality, the truth is not very sensational: The vaccine is highly effective & working exactly as intended.
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Youyang Gu
@youyanggu
By my estimates, Covid case rates among fully vaccinated individuals are currently ~4-7x lower than those that aren't fully vaccinated. This is based on weekly data out of LA County. Unfortunately, our federal government has no real-time data on this. twitter.com/youyanggu/stat
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Youyang Gu
@youyanggu
So the back-of-the-envelope calculation suggests that the vaccine is ~80-85% effective against the Delta variant, which aligns with the latest research. Still very high! And of course, if you're fully vaccinated, hospitalizations and death rates are even lower.
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Youyang Gu
@youyanggu
By my estimates, Covid case rates among fully vaccinated individuals are currently ~4-7x lower than those that aren't fully vaccinated. This is based on weekly data out of LA County. Unfortunately, our federal government has no real-time data on this.
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Youyang Gu
@youyanggu
For those asking where I got the estimates of "~75% of new cases are among the unvaccinated", below is the latest data from LA County. You can see that the % of new cases that are fully vaccinated is steadily rising over time. publichealth.lacounty.gov/media/coronavi dashboard.publichealth.lacounty.gov/covid19_survei
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Youyang Gu
@youyanggu
That said, I do think there's too much focus on modeling cases/deaths. For ex, I've haven't seen many efforts on vaccination forecasts or infections/immunity estimates. There may be some reluctance in the general scientific community to do this, so it's hard to blame one entity.
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Youyang Gu
@youyanggu
Thanks
@ScottGottliebMD
! On data, research & messaging, there’s lots of room for improvement at the CDC. For modeling, they were right in enlisting
@reichlab
to run Forecast Hub: cdc.gov/coronavirus/20 They’ve crowdsourced 30+ teams for weekly updates.
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Scott Gottlieb, MD
@ScottGottliebMD
More than a year into the pandemic and we still don’t have reliable, timely modeling of where things stand coming out of CDC. It simply doesn’t exist. Hopefully heroes like @youyanggu and others get back into game.
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Youyang Gu
@youyanggu
I've seen numerous misleading media headlines such as "All Covid patients in L.A. County hospitals are unvaccinated" But according to LA County themselves, there have been 213 hospitalized among the fully vaccinated. I hope to see more accurate reporting in the media!
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Youyang Gu
@youyanggu
To illustrate, this is the period in question for which LA County concluded "99.6% of cases are among the unvaccinated". 97% of cases happened before the vaccine was available to the general public! IMHO, putting out misleading data is not the best way to combat misinformation.
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Youyang Gu
@youyanggu
To summarize my thoughts on the Delta variant: 1) It poses a real risk to those with no immunity. 2) The virus is here to stay. There’ll be more variants. This is the new normal. 3) Regions with larger outbreaks now will see smaller outbreaks in the winter & vice versa.
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Youyang Gu
@youyanggu
If Malta had the same population as the US, they’d be reporting 130,000 cases, 5x higher than the current US daily average. So the finger pointing centered around vaccinations is fairly pointless (no pun intended). That said, this also means that outbreaks could get worse.
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Youyang Gu
@youyanggu
Not a single country in the world has vaccinated enough people to stop the Delta variant. Malta, the world’s most vaccinated country (~90% of adults), saw its COVID-19 cases increase from 1 a day in June to 200 yesterday. We must all adapt & learn to live in this new normal.
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Youyang Gu
@youyanggu
Of course, this is a new normal - we will never return to pre-pandemic normal. The Delta variant will be around. People will still be infected, even among the vaccinated. But that's expected. Efforts must continue to focus on vaccinating the vulnerable population.
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Youyang Gu
@youyanggu
Since I began making vaccination projections in Dec 2020, I have consistently predicted a return to normal by Summer 2021. Some said it was too optimistic, others too pessimistic. It appears that as of this week, all states (minus HI) are fully reopen.
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Youyang Gu
@youyanggu
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I launched a new page that shows the path to US COVID-19 herd immunity: covid19-projections.com/path-to-herd-i It's built on the assumption that herd immunity will be achieved via vaccination and natural infection. Tl;dr version: I estimate a "return to normal" by June/July 2021.
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