Wanted to summarize my favorite article which gives us data on how long immunity to natural infection or vaccination is expected to last (hint: years). Had chance to look at closely (sorry picture shows sperm, that is not related!). Dan J. Science. science.sciencemag.org/content/early/…
okay, so to remind us, there is innate immunity (non-specific immune response to infection that can actually get us in trouble with COVID-19 if too much) and adaptive immunity (humoral means antibodies; long-lived memory cells are B cells and T cells (CD4+ and CD8+) that will
protect us if we see the infection again. This study looked at 188 (80 male; 108 female) patients recovered from COVID-19 (93% mild; 7% hospitalized) over 8 months. Longitudinal samples assessed circulating antibodies, memory B cells, CD8+ T cells, and CD4+ T cells
over 8 months. Happily, memory B cells specific for the spike protein or receptor binding domain (RBD) were detected in almost all COVID-19 cases, with no apparent half-life at 5 to 8 months post-infection (go on and on!). Memory T cell half-lives were also long
over 6 months in this cohort (~125-225 days for CD8+ and ~94-153 days for CD4+ T cells), comparable to the 123 days half-life observed for memory CD8+ T cells after yellow fever immunization - this is aa vaccine usually given once over a lifetime!! Antibodies also lasted, but
slight declines over time with spike protein (also measured Abs to receptor binding protein). Super heartening paper that immune memory will be durable after COVID-19 natural infection or vaccination for SARS-CoV-2. Yay!!!

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More from @MonicaGandhi9

14 Jan
Johnson&Johnson published results of phase I/II study of vaccine today. This trial not designed to look at vaccine efficacy yet (not high enough #'s enrolled) - just safety & "immunogenicity" (defined by antibodies but we know memory T/B cells last long)
nejm.org/doi/full/10.10…
J&J product also an adenovirus vector (replication-incompetent so won't give you cold!) encoding FULL-LENGTH spike protein of #SARS-CoV-2. Like the full length so that pesky mutations shouldn't get in way. Enrolled in Belgium/U.S. and cohorts given either low dose or high-dose
vaccine, either 1 or 2 doses given 56 days apart. 805 people evaluated. Bottom line? Safe with 40% injection site reactions; very mild other reactions. Neutralizing-antibody titers in 90% on day 29 after the first dose, 100% by day 57 (2nd dose increased titer). Also measured
Read 5 tweets
13 Jan
Ok, let's do thought experiment. Why is #COVID-19 terrible and wreaked havoc? Because it can cause severe disease in some (vulnerable) unlike its cousins- the coronaviruses that cause colds. Say you don't believe the suggestive AztraZeneca nor Moderna data that shows asymptomatic
infection reduced. Say you don't think there is biological plausibility that a robust immune response blocks nasal infection. However, with vaccine >95% of population did not even get symptoms from COVID and nearly 100% did not get severe disease.
You have just turned this new virus into even less than a cold. How can we not be messaging hope and optimism after mass vaccination and pushing as hard as we can go get there? How can we not be messaging close contact after mass vaccination, crowds, in-person, etc.?
Read 4 tweets
9 Jan
Please allow me to go back to this question of "do vaccines prevent transmission?". What do vaccines do? Stimulate antibody (from B cells) and T cell responses (not often measured) and then a "boost" of 2nd dose helps stronger memory B/T cell to form.
Once you get vaccinated, should be able to block both the entry of the virus into your body & we certainly know symptomatic disease blocked by 95% (Moderna/Pfizer). However, latter trials just didn't look at asymptomatic infection & didn't swab every week because time of essence
But Oxford/AztraZeneca trial did swab every week & asymptomatic infection reduced substantially so we can say with relative confidence now that what is EXPECTED to happen will happen- the person who got the vaccine is safe from disease (what really matters) & spreading to others
Read 5 tweets
8 Jan
Perhaps ID doctors at blame for not explaining well enough to teachers that 1) risk can be mitigated by non-pharmaceutical interventions (masks, distancing, ventilation) even with new variant; 2) vaccines will make you safe; 3) vaccines will reduce transmission (although you safe
know you care about transmission; 4) surface/toilet transmission not factors. I would be happy as ID doctor to get on Zoom and explain modes of transmission to any group of teachers and how vaccines work. Will make talk easy and answer any ?. Please take me up on it in SF!
will show you all the data. Not on how school opening safe since I know not as convincing to some but on how virus works, how vaccines work, how the immune response works, will show you all data and go over all of it. Please take me up on it. So sorry if we are at fault.
Read 4 tweets
8 Jan
Pfizer study shows vaccine should work against this B.1.1.7 UK and South Africa variant of SARS-CoV-2. mRNA sequence in Pfizer vaccine likely propietary but Pfizer took a virus with the N501Y mutation and tested it in plasma of 20 vaccine recipients
apnews.com/article/intern…
The blood from these 20 people who got the vaccine were able to "neutralize" (kill, basically) the virus which means vaccine should work against this mutation. Now, the S. Africa strain has other mutations so more need to be tested but it is a good study! Also, if a variant does
arise that the vaccine may not work against, the mRNA technology can apparently easily be "tweaked" to help a modified vaccine work against a new variant. To explain this a bit more, you know how we need an influenza shot every year? This is because influenza A has two proteins
Read 9 tweets
6 Jan
Wanted to address this one-dose, two-dose vaccination question. NO ONE to my knowledge is suggesting that one dose only be given; suggestion was whether 2nd dose could be given later to allow current supplies of 1 dose to vaccinate more. What would be evidence for this?
In the AstraZeneca/Oxford trial, Lancet paper did not mention this but the data presented to UK showed that extending time between doses led to MORE immunogenicity. Here is slide below (12 weeks >9 weeks >6 weeks) Image
Known in vaccine world that we don't want too short of an interval between doses, okay to give booster shots after a long time (which is why - if childhood vaccines have gaps- we just start where we left off, not repeat). Why 2 doses better than one? To build memory immune system
Read 6 tweets

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