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Michael Lin, MD PhD 🧬 Profile picture
@michaelzlin
Jun 10, 2021 • 12 tweets • 4 min read • Read on X
The J&J vaccine is <10% of vaccinations in the US, and ~0% outside, so it isn't studied as much as other vax. In particular how well J&J works against Delta (b.1.617.2) hasn't been discussed, whereas we know a lot about Pfizer/Moderna/AZ. So I've decided to take a stab at it.
🧵
2) I was motivated by this CNN article which revealed recent findings that the Pfizer/BioNTech vaccine (and likely the similar Moderna) are 88% protective against symptomatic Delta infection after dose 2 (good), but only 33% after dose 1 (not so good)
cnn.com/2021/06/10/opi…
3) The article says "Of note, this variant appears to be extremely transmissible, and the first dose of a two-dose vaccine regimen is much less effective than is the first dose against other variants." What about J&J which only has 1 dose?
4) Will 1-dose J&J act more like the first dose of a two-dose RNA vaccine regimen against Delta (33% protection) or more like the second dose (88% protection)?

My best guess is that it will be 64%. Why?
5) The J&J vax is 64% effective against Beta (501Y.V2 from South Africa) when looking ≥1mo after vaccination (vs 66% for original). Beta has a E484K mutation that reduces potency of neutralizing antibodies (nAbs) elicited by the J&J vax by ~5x.
rupress.org/jem/article/21…
6) The Delta variant has a nearby mutation T478K that reduces nAb potency by 6x. So escape from nAbs by Beta and Delta are very similar. Image
7) So because Delta and Beta resists nAbs similarly, we might expect J&J efficacy against symptomatic Delta might be similar to that against Beta: 64%. Protection against severe disease would be predicted to be similar, at 82%.
9) It's not known why J&J didn't show much efficacy drop from original to Beta with the 5x drop in nAb potency. This contrasts with the drop in 1-dose RNA vax efficacy from 80% on original to 33% on Delta being predicted by nAb potency drop alone.
nature.com/articles/s4159…
10) It could indicate that J&J elicits better cellular immunity than the RNA vax, but this is just speculation. It would be nice if studies can be performed on the post-J&J T-cell and nAbs responses against original and B.1.617.2 so we can tell.
@michaelmina_lab @florian_krammer
p.s. J&J efficacy numbers taken from below article
nejm.org/doi/full/10.10…
There's an assumption in the analysis that if J&J is remaining effective against variants due to cellular immunity, then Delta won't resist that any more than Beta. Many mysteries with this vaccine.
Dr. Barouch (ex-classmate, running studies of J&J vax at Harvard) also concludes the robust T cell immunity may account for J&J maintaining efficacy against Alpha and Beta variants. If so, then likely will be true for Delta as well. bostonglobe.com/2021/06/09/nat…

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More from @michaelzlin

Michael Lin, MD PhD 🧬 Profile picture
Sep 3
New study in JAMA: azelastine antihistamine nasal spray reduced occurrence of COVID19 and common cold by 67% in a placebo-controlled (but small) study.

Azelastine in the US is sold OTC as Astepro, just $10 at CVS (with coupon). Note it's not the more common steroid nasal spray Image
Azelastine is generic now, and this was an academic study. Little interest by companies to test off-patent drugs. It was done in Germany (zero interest by US to do COVID-19 research now)

Trial was n=450 split into azelastine and placebo groups. That's large by academic standards
Subjects took azelastine 3x/day for 8 weeks. SARS2 antigen testing was done 2x weekly by study personnel, so not self-reported which is good. Those with symptoms but SARS2 negativity were tested for other viruses. Solid study.

SARS2 rate 2.2% treatment v 6.7% placebo, p = 0.02 Image
Read 20 tweets
Michael Lin, MD PhD 🧬 Profile picture
Aug 19
People have been asking about the SARSCoV2 (COVID19) vaccine outlook so I'll summarize as best as I can. But overall, the current situation is chaotic and in constant flux, and if FDA is trying to apply consistent criteria then they haven't shown it yet
Right now there are 4 vaccines from 3 companies covering 2 technologies with FDA approval in some form or other. The approvals are for different age ranges and risk categories. In addition each August or September new formulations have to be reapproved, kind of like influenza.
The vax are Comirnaty (Pfizer), Spikevax (Moderna), mNEXSPIKE (Moderna), and Novaxovid (Novavax). The first 3 are RNA, the last is protein. HHS.gov shows who qualifies for each, but hasn't been updated with mNEXSPIKE. Must be the DOGE cuts hhs.gov/coronavirus/co… Image
Read 22 tweets
Michael Lin, MD PhD 🧬 Profile picture
Jul 6
In case you think cameras can detect cars or people ahead of them through the glare of the sun, or that AI has learned to react to ambiguous situations with the, well, intelligence of humans, read this Image
It's a frightening and sad story (a grandmother was killed) and I'm surprised to find out about it only now.

There's clear evidence from the Tesla's own cameras that no kind of image processing can beat glare (and that FSD lacks all sense of caution)
bloomberg.com/features/2025-…
Glare happens when light rays from the sun get scattered by water or dust in the air at every lit location to new directions. That means air between an object and the camera can scatter sunlight toward the eye or camera.
Read 7 tweets
Michael Lin, MD PhD 🧬 Profile picture
May 18
FDA has granted regular approval to the Novavax vaccine. What does this mean? A lot of things, all good.

1- It proves Novavax has met efficacy and safety criteria to merit approval outside of the emergency use situation.
Novavax is safer than the RNA vaccines, but ironically the RNA vaccines received full approval earlier than Novavax. That meant Novavax was the only COVID vaccine which vaccine skeptics could incorrectly claim was not safe enough to receive regular approval.
2- Novavax will get to participate in annual booster updates on the same terms as the RNA vaccines. This year's advisory committee for booster strain selection has already been scheduled.

3- All health insurers should now cover Novavax.
Read 14 tweets
Michael Lin, MD PhD 🧬 Profile picture
Apr 18
"Novavax had 1.7 systemic symptoms compared with 2.8 in Pfizer recipients. In total, 43.8% of Pfizer vaccinees reported at least one symptom of moderate or higher grade, compared with 24.2% of Novavax"

@RobertKennedyJr in case you didn't know. It's also more broadly protective. Image
This is the 2nd controlled study to show about half the side effects rate for Novavax vs Pfizer.

Of the 3 covid vaccines, Novavax is the only one still on EUA. Happens it's the smallest of the 3 companies and hasn't hired ex-FDA staffers.

Article below.
cidrap.umn.edu/covid-19/novav…
FDA had a deadline of April 2 (this month) to decide on regular approval for Novavax, and reportedly was going to, except Peter Marks resigned the day before. Sadly he didn't sign the approval before he left. Was different for Pfizer and Moderna, who got early review and approval
Read 9 tweets
Michael Lin, MD PhD 🧬 Profile picture
Mar 25
Our NIH grant to discover coronavirus antiviral meds was terminated today.

With this grant, we had developed a better SARSCoV2 inhibitor than Paxlovid, and we recently discovered an improved drug that looks better than Pfizer's own second-generation inhibitor. Image
This is part of a complete elimination of COVID19-related research, including on long COVID.

The rationale given is that the pandemic is over.

In reality, people are dying of COVID at several times the rate of flu, and still getting long COVID.

arstechnica.com/health/2025/03…
This goes against RFK Jr's stated intention to concentrate on chronic disease.

Long COVID is a bad chronic disease to get, and there are reports of long COVID cases getting better immediately after treatment by protease inhibitors such as the ones we are improving.
Read 9 tweets

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