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Shane Crotty

20 May, 10 tweets, 3 min read

@DerekStaahl

My comments on an excellent new study on delaying the 2nd dose of Pfizer COVID vaccine to 3 months, in people over 80. 🧵

A well done story by local journalist @DerekStaahl.

10news.com/news/in-depth/…

Overall, this new delayed dose vaccine study it is a high quality study. Bottom lines:
🔵 The UK delayed vaccination is working for them, and allows vaccination of more people. And the new data support that. I am really happy about that!

🔵 But, if you have enough doses, getting the 2nd dose on the recommended schedule is still probably better.

🔵 Also, if you are in America and you miss your scheduled 2nd dose, don't worry! Your opportunity has not expired! Just get that 2nd vaccine dose when you can! Whether it is at 6, 8, or 12 weeks you will still get the benefit of that second dose. But please get the 2nd dose!

Here's the preprint.
doi.org/10.1101/2021.0…

There is an impressive 3-fold improvement in antibody responses after the 2nd dose!

However, there are three major drawbacks:

1- No neutralizing antibodies against variants after 1-dose of RNA vaccine. Those antibodies are present after 2-doses. (other papers)

2- Protection against COVID after 1 RNA vaccine dose is not as good as protection after 2 doses.

3- The T cell responses were 3-fold lower in the older individuals on the 12 week delayed dose schedule. That is unexpected, and worth further study. To me, that loss, combined with the points above counteracts the post-2nd dose antibody gain for older individuals.

Regarding protection after 1-dose of RNA vaccine, the excellent UK SIREN study showed ~75% protection for 12 weeks. Similar data from Scotland too. But there is also data from a large study in Denmark that found no protection from 1-dose for people in long-term care facilities.

Protection against COVID in the Danish study was only observed after 2-doses of vaccine.
(links to all three studies)
medrxiv.org/content/10.110…
papers.ssrn.com/sol3/papers.cf…
sciencedirect.com/science/articl…

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More from @profshanecrotty

Shane Crotty

@profshanecrotty

12 May

For people on the fence about getting the COVID-19 vaccine for their kids, given the approval today, here is COVID-19 vaccine information. 🧵

1/ Kids get COVID-19, including very serious disease.

There were over 35,000 kids hospitalized with COVID-19 in America this past year.

Among pediatric hospitalization cases, 50% had no risk factors.

covid.cdc.gov/covid-data-tra…

https://twitter.com/profshanecrotty/status/1392125283709321219?s=20

2/ The vaccine is incredibly successful in kids 12-15, and very safe

https://twitter.com/profshanecrotty/status/1392125283709321219?s=20

Read 4 tweets

Shane Crotty

@profshanecrotty

11 May

The FDA expanded the Pfizer/BioNTech RNA COVID-19 vaccine to 12-15 year olds yesterday.
🔵Excellent protection (100% = 0 cases versus 18)
🔵Excellent safety (On to younger children already)
🔵Better antibodies than adults

Also bodes well for other COVID vaccines in kids!🧵

FDA CBER head Dr. Marks:"It was a relatively straightforward decision. The response..was excellent and in fact it was even better, really, in the younger age group than it was in the 16-25 age group. The safety profile was very similar in 12-15-year-olds as in 16-25-year-olds."

fda.gov/news-events/pr…

Read 8 tweets

Shane Crotty

@profshanecrotty

6 May

Moderna results are out for their booster vaccines!
🔵 Boosting with same vaccine generates good antibodies against variant B.1.351
🔵 Boosting with a B.1.351 vaccine generates even better antibodies
🔵 Safe
🔵 The booster vaccine was made and tested with exceptional speed!
🧵

The reason for excitement about this is that there has been uncertainly for months about vaccine efficacy against B.1.351 (1st seen in South Africa) and similar variants. Since January I have been saying:

Moderna, Pfizer, J&J and other vaccine companies have all stated that they are developing B.1.351 boosters or similar. Today is the first public data on such a vaccine.

investors.modernatx.com/news-releases/…

Read 8 tweets

Shane Crotty

@profshanecrotty

5 May

Big knowledge gap was will the COVID RNA vaccines work vs B.1.351 and P.1 variants. Now Pfizer protects well vs B.1.351!
🔵 ~75% against infection
🔵 ~97% against severe/fatal disease

Very good news for the rest of 2021 for any countries using Pfizer and Moderna vaccines! 🧵

B.1.351 and P.1 (1st found in South Africa and Brazil) have been the two biggest variants of concern that have a degree of antibody escape. As of this morning (and February), some vaccines (AZ) showed only 11% effectiveness against B.1.351 cases,

and the best clinical trial data was ~50-66% vaccine efficacy against B.1.351 cases (J&J and Novavax), and only data for non-hospitalized cases (because of the size of the studies). Leaving lots of uncertainty.

Read 12 tweets

Shane Crotty

@profshanecrotty

5 May

@ImmunityCP

The Crotty Lab journal club this week was from the Brink lab. Sundling et al.: “Positive selection of IgG+ over IgM+ B cells in the germinal center reaction”. 🧵 @ImmunityCP

doi.org/10.1016/j.immu…

Using various mouse models, the authors sought to understand the process by which IgG antibodies come to dominate mature antibody responses.

High-affinity IgG+ germinal center B cells are positively selected over high-affinity IgM+ germinal center (GC) B cells via a process based on antigen receptor constant regions

Read 4 tweets

Shane Crotty

@profshanecrotty

4 May

Oral SARS-CoV-2
I love this paper! Important demonstration of SARS2 infection in the mouth. And outstanding paper on oral biology and immunology relevant for viral infections. I learned so much! 🧵

nature.com/articles/s4159…