@DrEricDing @VirusesImmunity @PeterHotez This is a great question

The vaccine is not necessarily a more trusted source of immunity. Both an infection AND a vaccine are likely to induce good immune responses. All of the information we have suggests that immunity to infection for this virus is... well... as expected

@DrEricDing @VirusesImmunity @PeterHotez However, to the questioners point, we are hoping the vaccines will induce potent and long lasting immunity. The vaccines are designed specifically to direct our immune response to look in the right spot - vs searching all over the virus...

@DrEricDing @VirusesImmunity @PeterHotez The leading vaccines are all designed to induce, primarily, an antibody response that specifically blocks virus entry. To do this, they display a piece of the spike protein - the key to unlock entry into the cell.

@DrEricDing @VirusesImmunity @PeterHotez If the immune system learns just one thing well - and that is to create an antibody that blocks the key from being used... well that’s a massive win. It’s the type of response that is really ideal - prevent infection in first place rather than clean it up when it happens.

@DrEricDing @VirusesImmunity @PeterHotez We call this type of immunity sterility. Or slightly different but similar, neutralizing. It neutralizes the virus upon entry so it can not bind.

Ok. But why am I talking about all of this when your question was about vaccine vs infections...

@DrEricDing @VirusesImmunity @PeterHotez When you get a natural infection, the immune system has a bit more of a “choose your own adventure” to deal with.

So many different knobs and handles and other things on the virus to potentially recognize and memorize.
@DrEricDing @VirusesImmunity @PeterHotez Some of these proteins and virus bits will be very immunogenic but maybe not the most useful to recognize - like forming an antibody to someone’s pinky toe. Just not that useful. And others like an antibody to the receptor binding domain are very useful.

@DrEricDing @VirusesImmunity @PeterHotez All different people have slightly different responses. So an immune memory formed from a natural infection may or may not be all that useful.

But at the same time, w a natural infection, you have opportunity to form LOTS of new distinct memories, which can prove beneficial.

@DrEricDing @VirusesImmunity @PeterHotez Some of the new memories will be remembered by antibodies and be useful. Some not as much (though new research shows that even non-neutralizing antibodies are crucial)

Importantly T cells work very differently from antibodies. Recognizing a pinky toe may be very beneficial!

@DrEricDing @VirusesImmunity @PeterHotez Essentially if you can induce a good T cell response and it remembers a part of the virus well (an epitope) then it can prove v useful

The vaccines were not designed for this purpose (induce T cell memory) as much as their focus on a neutralizing antibody response.

@DrEricDing @VirusesImmunity @PeterHotez But that said They appear to be inducing T cell responses AND antibody responses which is.

There is some precedent too for a narrow response (ie directed at spike only) to be potentially better than a broad response induced by infection...

@DrEricDing @VirusesImmunity @PeterHotez HPV vaccines, despite being narrow targeted vaccines tend to perform better than natural infection to induce robust lasting and cross reactive immunity.

Why, is under investigation.

Additionally, vaccines can be tuned to induce the best response possible!

@DrEricDing @VirusesImmunity @PeterHotez So much of “locking in” good memory responses is about boosting. This happens naturally w Re-exposures (yes reinfections are not necessarily bad - just like training... repetition is good)

Vaccines can be calibrated appropriately for this - not exactly science but improving

@DrEricDing @VirusesImmunity @PeterHotez So, to conclude, vaccines can be calibrated and targeted for maximal immune response FOR THAT PROTEIN.

But the downfall is it’s a narrow vaccine. Mutations can more easily enable immune escape (none identified yet!). Diversity in responses can be helpful.

@DrEricDing @VirusesImmunity @PeterHotez In this case though, most beneficial is getting a vaccine to drive immune memory instead of an infection. All signs suggest it should work fairly well, if not excellent?


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More from @michaelmina_lab

23 Nov
Rapid Antigen tests are very sensitive at Ct < 30

Above which-too little live virus to detect

Ppl worry transmission could occur at Ct > 30 and thus missed by Ag test

Transmissibility is NOT BINARY
Possible at 34? Yes
Likely? No.

This graph helps place Cts in context!

1/ Image
(If do not see the full graph above - please click on it)

Easy to forget Ct values are LOG scale

They place as much emphasis on an increase of 1000 viral particles as they do an increase of 1,000,000,000!!

But when we change from a Ct scale to a scale that shows the number of viruses withouth "zooming in" on the low end, we see just how stark a different 20-25 is versus 30-35.

Read 8 tweets
21 Nov
(SHORT) Thread

Another terrific study showing rapid tests WORK & can be key tools to combat this virus

Of 897 people w high virus (Ct<25): 888 were detected w Rapid Test

Sens: 99.1%
Spec: 99.5%


*repeat tweet b/c typo in last

If these ppl were screening, this would be 888 INFECTIOUS ppl who'd KNOW they’re contagious–and be empowered to act IMMEDIATELY Instead

In USA today, these 888 INFECTIOUS ppl would simply NOT be tested OR find out ~3-7 days later -> often AFTER contagiousness clears!

In this study there was a specificity of 99.5%!

In other words, out of 1000 tests, 5 people would be called falsely positive

This is OK–simply test again- w another rapid confirmatory test that should come with the first test. Those 5 would NOT be likely to be pos on both

Read 8 tweets
20 Nov
Right... lets keep focusing on PCR lab based medical testing for a public health war

A public health test with a:
-24 hour delay is just OK
-48 hour delay really losing its use
-72 hour delay almost irrelevant for transmission
-96 hour delay - waste

2/ We have to recognize that the tools we need to fight this war are sitting right in front of us.

Blocked by a medical enterprise that can't see a forest, just trees

A government that fails to recognize the gravity of the situation we are in

3/ Some people say rapid antigen testing is not good enough. "Some infected people might slip by!"

First: Essentially everyone is "slipping by" right now. People are either tested post-transmissible stage or getting results too late to act.

Most are just not getting tested!
Read 12 tweets
19 Nov
South Dakota

68,671 cases
Pop: 885,000
HIGH test +ve %; i.e. not nearly enough testing

I'd be surprised if catching >1 in 5 cases

If so, does 68,671 => 343,000 cases?

And if so... 39% infected...is SD nearing Herd Immunity?

Should serosurvey much of SD to understand if so.
Note: It's tough to know what the true detection rate is. Is it 1 in 2, 1 in 5, 1 in 8 detected?

We don't know for sure.
Either way... SD has a LOT of it's pop infected.

Since it's one of highest per capita states, will be imprtnt to monitor this state
And no - I am NOT suggesting herd immunity as an option. I'm simply stating the numbers up there and suggesting that we monitor to better understand what has and what will happen.
Read 4 tweets
18 Nov
For anyone wondering what a best-in-class rapid antigen test looks like. This is the @AbbottNews PanBio rapid antigen test.

If you lift up the plastic top (which is cheap) it is a simply paper strip (that white part with the red line)....

These are exceptionally cheap w/ very good accuracy to detect people when they are carrying infectious virus

Extremely easy to use
Simple design

I suggest a model where you reuse the plastic shell (like contact lenses) and just change the paper strip. Simple.

It is really unfortunate though that this particular test is NOT sold in the US. It is sold outside of the United States.

Nevertheless - this is to show that THESE TESTS EXIST.

The US Government should be making them in the 10's of millions daily.

Instead, Americans are dying
Read 4 tweets
18 Nov

• NO lockdowns
• NO waiting for vaccines
• Reverses cases in weeks

A true public health approach focused on the ppl

To end the public health *WAR* we are in.

RAPID At-Home COVID Testing for All

This Plan works WITH the people and meets them where they are.

It works WITH all the other public health approaches we are already taking - it does not replace them

It is bold and and ambitious - and addresses the fact that we are actually in a war with a virus...

It is time the government STOPS the nonsence of treating this like scattered medical problems to be addressed medically

We MUST address the pandemic as a public health problem - with the RIGHT TOOLS - only then will the medical issues resolve

Not the other way around

Read 15 tweets

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