Michael Mina Profile picture
Epidemiologist, Immunologist, Physician, Harvard Public Health/Medical School. Discuss vaccines, immunity, infectious diseases, public health
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25 Oct
This is incredibly sad and bad news for the US.

In only 3 days, the 14-day average change in #COVID19 HOSPITALIZATIONS has skyrocketed from 7% to 15%!

This means hospitalizations are not simply increasing but accelerating upwards at a fast pace.

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For the 14 day average change to >double in only 3 days means that the actual current change is much more than 15% (to pull a 14-day change that far up in only 3 days means the past three days have seen remarkably large increases).

This is not some fear tactic. This is peoples lives. This is the proper functioning of our healthcare system (already stretched to the brim at baseline).

We are only at the beginning of this “spike” and it could continue accelerating up for months!

Read 6 tweets
24 Oct
I’m glad tests are becoming more available... but not like this. Not for $130!!! 10x more than cost!

I’ll say it here, #COVID19 has become commoditized. Labs are making millions of $$$ bc people are desperate. This is not how public health should work

This is for a saliva based PCR test. The test actually likely costs <$10.

Add overhead for staff and the lab. Maybe - MAYBE - get to $25. But $130. This is extortion in my opinion.
#SalivaDirect on the other hand (as one example) has made a strong concerted (and so far successful) effort to drop prices and raise awareness that these exorbitant prices need not exist

Not surprising - they are not-for-profit and doing what’s right

@awyllie13 @NathanGrubaugh
Read 5 tweets
24 Oct
#COVID19 Cases at all time high.
#COVID19 Hospitalizations up 40% in last month

Deaths lag cases! Herd Immunity = deaths

Step 1) Stop Virus
Step 2) Open Up

Step 2 will NOT cause Step 1 without 100,000’s more deaths.
Step 1 WILL allow Step 2 to happen safely.

Solutions exist!
We don’t have a vaccine. Rx won’t bail us out

We must stop spread.
Economic/human fallout too costly for total shutdown

We must think creatively and can’t let perfection paralyze us

Simply, we must know who’s infectious and remove them

Frequent rapid tests can enable this
**Natural Herd Immunity that is **
Read 4 tweets
22 Oct
This happened faster than I expected, and I’ve been anticipating major upswings. We’re unfortunately just at the beginning

Going into fall w 60k cases/d means winter may well dwarf the spring and summer peaks

It’s up to us to change the course. But won’t w/out proper leadership
I’m referring to the fact that we are right back to our summertime peak. So early into this long winter.
This makes me mad as hell and really really sad. Not just for the ppl who will die (1000/d right now) but for the stores that will close, the families that will lose jobs, the health effects due to COVID and as important as anything else, the mental health effects that will occur
Read 5 tweets
21 Oct
Severe #COVID19 resulting from Original Antigenic Sin??

May be a contributor. Makes sense

Superb paper evaluating cross-reactivity between donor B cells targeting SARS-CoV-2 and other seasonal Coronas.

This figure (2) is really depicts it well...


This figure depicts one persons different B cells (x axis) across 3 different weeks in time, and how they react to SARS2 spike (y axis - broad categories) and how the secreted antibodies from those B cells reacts with other seasonal coronaviruses (y axis - smaller categories)

What is remarkable is the change over time from day 9 to day 16 in the binding of antibodies to the seasonal coronavirus OC43 by B cells elicited by exposure to the SARS-CoV-2 Spike ectodomain (S ecto).

Read 11 tweets
16 Oct
NEW! research shows rapid antigen tests can work in a real world setting - with asymptomatic and symptomatic people. The rapid "paper-strip" antigen test called the BinaxNOW detected >90% of people with high viral loads who are likely to be infectious

I've written about the BinaxNOW from @abbottnews before and why these types of tests can be 'game changers' for our ability to combat this virus

As expected... the BinaxNOW did NOT detect all PCR positive people... only ~60%

BUT DID detect >90% of those with high/contagious virus load. THESE ARE THE PPL THAT MATTER most when trying to cut off transmission chains.

Read 20 tweets
14 Oct
Rapid test data!

@MarionKoopmans and team evaluate rapid “paper-strip” Ag tests against likely contagious virus samples

Here @AbbottNews PanBio and SD Biosensor rapid tests perform very well to detect infectious virus

But, not all tests are equal

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The authors evaluated a number of different tests against PCR positive and culture positive specimens. (Culture positive is generally appreciated as representing likely transmissible virus).

They find a large disparity across different tests...

Against culturable virus, they find that the Abbott PanBio Test and the SD Biosensor (Neither available in the US right now) perform very well. An additional 3 tests were evaluated 2, also looked quoted good but the rapigen performed quite poorly.

Read 4 tweets
14 Oct
New research! Starring... Ct values!

We endeavored to ask:

Can we create a brand new metric to know if #COVID19 is increasing/decreasing without staring at case counts & fractions positive - both greatly obscured by test practices.

Yes! w/ Ct values!

In this incredible Tweet thread 👆 @jameshay218 describes the new work - we hope will lay new groundwork for public health authorities to track this/future viruses & if control strategies are working

Work also w co 1st author Lee Kennedy-Shaffer, @mlipsitch & @SanjatKanjilal
One piece that is so cool about this method is we do NOT need a time series of case data to create a trajectory (those little bars on @nytimes website or google that we’ve all stared at for the past 9 months to see trend up vs down in cases). We can do it from a single day!

Read 7 tweets
13 Oct

This virus is not happening in a vacuum where no information existed previously

On Immunity, On testing, On serology, On transmission, On masks, On treatments...

We must stop this narrative that we know nothing of this virus until we learn it anew - again.

The constant drum beat of “we do not know that yet” is tiring.

We KNOW SO MUCH! about SARS-CoV-2 and COVID-19. We knew it before this virus was ever discovered!

We’ve watched since January with study after study reaffirming out expectations of this virus in SO MANY WAYS.

In many we ways we got lucky on this front.

Take HIV for ex. HIV was a new virus for which we generally did have to rewrite the text book

But this virus is different from HIV in that it is behaving in almost all ways per the “textbook”.

Read 19 tweets
13 Oct
So important in this pandemic to NOT let RARE events make the headlines & grab our attention

@NPR - this should NOT be a headline unless you’re going to have daily headlines that say “Millions NOT reinfected today with COVID19”

People are scare enough

Re-exposures are essential to build our immune system. This is not in question. They are like training.

But like anything, when enough people get a re-exposure, there are going to be rare cases here and there that go awry and someone gets more sick the second time.

But this is rare and should NOT be interpreted as people will not build protective immunity and that vaccines will not work.

The take away from this piece should be “In a rare event, a person in the US gets a severe second infection with SARS-CoV-2”

One other point

Read 7 tweets
12 Oct
Trump tested negative on @AbbottNews BinaxNOW test. His MDs are using for evidence of no longer contagious

I don’t disagree - but like use of tests to stop transmission - this is just one piece. Frankly, in this context, it’s being used out of context...

The most important point of deployable rapid tests are that they can be used by many people, frequently!

But should not be used as confirmatory testing of -ve PCRs. This doesn’t make sense and WH use for this confuses how these tests are most appropriately used.

These tests should be to screen ppl (frequently) for +ve results to identify people likely needing to be isolated

In this case @POTUS has had numerous PCR tests and is the president! He can get a viral culture test if he wants to go out w confidence he is not contagious

Read 5 tweets
10 Oct
IDNOW by @AbbottNews rapid test is what @POTUS uses

It's said to be poor w very low sensitivity - the news, @US_FDA and many others say so

But this is a mistake. It's a very good rapid test

I explain here at ~3:30
(Just found link from an old talk)

The short story is the main study from NYU that led to the low sensitivity claims used an extremely skewed sample set

If you remove from the paper just the +ve samples with a Ct value >40 (incredibly miniscule RNA loads), the sensitivity of the test jumps from 60% --> 90%!
If you take only samples with Ct values <38 (still on par w almost any other PCR test), then sensitivity jumps from 60% --> 95%!!

So the problem wasn't the test, it was the samples evaluated. 30% of them were at the very limit of detection of a SLIGHTLY better test
Read 6 tweets
8 Oct
Urgent @US_FDA @CDCgov #AndWhoeverWillListen

Rapid paper strip tests can be extremely powerful public health tools

But they cannot just be introduced without major information campaign AND clear algorithm for use - like the CDC HIV algorithm.


Despite high sensitivity when someone is likely contagious, and high specificity relatively speaking - 98%,

When deployed widely, a 2% false positive rate (1 per 50) is too high.

If deployed alone, a pop screening tests with a 1 in 50 false positive rate will immediately create a lack in confidence of the assay. This is already happening!

I’ve said it before - directly to FDA/CDC and here - we MUST have a clear goal and plan for these tests.

Read 7 tweets
7 Oct
Winter is coming!

If we do not get this virus under control now, we are in for a perfect and terrible storm

We are not taking the expected seasonality of this SEASONAL virus seriously!

Instead, we've assumed our efforts are responsible for decreased cases this summer...

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I worry very much that people are confusing the fact that this virus has transmitted in the summer for it not being very seasonal.

This is a grave mistake and misinterpretation...

The 'force of infection' of this virus is massive! Think of it like the momentum that the virus has to transmit

The huge number of susceptible people is what is allowing the virus to maintain transmission through the summer months - when other coronaviruses go to near zero.

Read 11 tweets
6 Oct
Important (but not surprising) study

Rapid Antigen tests may be MORE, not less, accurate to detect VIABLE virus (i.e. transmissible virus) compared to the more sensitive PCR.

But how?


We continue to see the use of the word “accurate” but accuracy depends on the target of interest. If the goal is to detect any evidence of virus at all (i.e. RNA remnants), then PCR will be more sensitive, more specific and overall more accurate.

However if the target is to detect VIABLE and thus likely transmissible virus - then it is possible that PCR can “overcall” positive results when in fact the sample contains just RNA and no viable virus.

Read 17 tweets
6 Oct
TRUMP is a DANGER to the US in a way that should be unfathomable for a sitting president

"Don't be afraid"... he downplays the virus that has killed >200,000 people on his watch---on the day he leaves the hospital. He is unfit.

His words will kill more
People may think I'm too outlandish with this tweet. I've bitten my tongue for 9 months watching this president act against all good public health policy... for what? To make a point? Politics? To seem strong? I don't know what. But it has harmed our country in massive ways

The US has failed in incredible fashion to get this virus under control. There are innumerable things we could have done better - but unfortunately I'd say few have been aided by our president. He's advocated against public health policy and downplayed the virus since day 1

Read 6 tweets
3 Oct
For those thinking "look proof that frequent tests dont work"... a wrong interpretation

This is the 1st transmitting event despite 100s (1000s?) of ppl crossing paths w president or through the White House. Testing has since March helped keep the WH generally free of virus.

It is far too easy when thinking about public health to see successes. The very nature of public health is that success is largely invisible. Reporting that no cases transmitted day after day is simply not a story. So we focus on where things go awry - its natural to do so.

This is the same issue as vaccines and preventive healthcare, and public health in general. It does not get the funding it needs because its successes go unreported and undocumented... out of sight out of mind. But it is the daily undiscussed actions of public health that matter
Read 4 tweets
3 Oct
About frequent rapid testing and the TRUMP White House:

I agree with ppl that the WH cluster f%^* is a shining example of how throwing caution to the wind in response to neg tests is a terrible idea

But it does NOT mean frequent rapid tests don’t help stop outbreaks

No single protective layer is 💯% for this virus. We need to remain vigilant.

We’ve said all along that frequent rapid tests help to stop spread similar to how masks help and should be considered similar to masks in how they are considered as a tool to curb outbreaks..

A frequent rapid test can detect MANY people who are infectious, but not everyone - just a bad swab (potentially intentional) can cause a positive to look negative.

But the point is that if used frequently, they can catch ppl early in their infection...

Read 10 tweets
30 Sep
To detect #COVID19 before it spreads to others, we need frequent accessible testing.

We cannot detect pre/asymptomatic people before they spread if we do not test frequently.

A new article in @NEJM by ⁦@DanLarremore⁩, Roy Parker and Me

1/x nejm.org/doi/full/10.10…
An ideal screening test is one with high sensitivity.

During a pandemic of a fast moving virus that transmits asymptomatically, it is difficult to detect people before they transmit to others.

This far we have focused almost all of our screening efforts on the use of the very sensitive (and specific - a good thing) qPCR.

The qPCR meets the molecular needs of detecting this virus. It has an extraordinary sensitivity.

But it is extremely limited

Read 11 tweets
29 Sep
The load of virus detected in the #COVID19 PCR test is a powerful piece of information for medical and public health use

Unfortunately it is usually not considered and thrown away before being reported

@RobertFService discusses in


Ct values aren’t perfect - but nor is listening to a heart or taking an X-ray. Nevertheless, these tests have their place when considered in context - as does the Ct value of the PCR

To discard is to throw out some of the most informative data we have about one’s infection

It can help determine whether a person is early or late in their course of infection. It can tell us about he direction of an epidemic. It holds immense value. We should consider its regular use as a crucial tool in this fight against COVID. Not toss it for its imperfections.
Read 5 tweets
28 Sep
BREAKING (not so surprising) NEWS:

The Trump Admin is touting rapid antigen paper tests. The @AbbottNews BinaxNOW assay is terrific and is a great start.

But don’t be fooled - the number of tests being distributed by the WH is simply not sufficient...

They are saying there are sufficient tests to be used daily or weekly by many many Americans in the coming weeks, but the actual number of tests they are distributing is no where near what is needed....

Distribution of 30 million rapid tests per month may sound like a lot, but across the US, it is 1 test per person per year!

This is not near the type of rapid test volume that is needed to make a major impact...

Read 8 tweets