Thread by @sailorrooscout

A study out of Northwestern University shows post-booster antibody levels not only exceeded antibody levels documented after natural infection with COVID-19, but after two doses of vaccine, AND levels after both natural infection AND vaccination as well.

Let’s talk about that!🧵

Here, researchers measured anti-receptor binding domain (RBD) IgG and surrogate virus neutralization of the interaction between SARS-CoV-2 spike protein and the human angiotensin-converting enzyme (ACE2) receptor, before and after COVID-19 boosters in healthy adults.

Participants e-consented and completed online surveys regarding COVID-19 viral history and vaccination status. Finger stick dried blood spot (DBS) samples were self-collected prior to booster administration and 6-10 days after receiving mRNA booster vaccine (paired samples).

Results were compared with data from a prior community-based study using the same protocols, which quantified antibody responses after diagnosis of COVID-19 or administration of a second dose of mRNA COVID-19 vaccine.

So what did they find? Researchers documented large antibody responses after the administration of the booster, with antibody levels that EXCEEDED levels documented after natural infection with COVID- 19, after two doses of vaccine, or after both natural infection AND vaccination

(i.e, Hybrid Immunity). Surrogate neutralization of B.1.617.2 (Delta) was high but obviously reduced in comparison with wild-type SARS-CoV-2. Researchers concluded this data supported the use of boosters to help prevent breakthrough infections and suggested that antibody-mediated

immunity may last longer than after the second dose of vaccine. “While waning antibodies may contribute to breakthrough infections, it is important to investigate the effects of boosters on cell-mediated immunity.”

YES, you cannot forget about cell-mediated immunity. Antibodies are just one part of the immune response BUT they can help us prevent the occurrence of breakthrough infections, especially in those that can’t mount a sufficient immune response in time. bbc.com/news/health-59…

Good thing is I have some additional studies I can give you guys that can give some more insight and help with study limitations! To start, the burning question: how long do they last? Initial data out of Israel shows 9-10 months, potentially even longer. timesofisrael.com/pfizer-booster…

Published in The Lancet. Peer-reviewed. Large sample size. Sound methodology. Real-world data. The study provides the largest peer-reviewed evaluation of the effectiveness of a third "booster" dose of a COVID-19 vaccine in Israel. thelancet.com/journals/lance…

Real-world data out of England on booster effectiveness shows OVER 90% vaccine effectiveness against symptomatic infection when comparing boosted vaccinated individuals to unvaccinated individuals. NOTE: these results were in HIGH-RISK groups.
khub.net/documents/1359…

Do booster doses increase neutralizing antibodies AND T-cell responses against SARS-COV-2? This study out of Chile on a booster dose of inactivated vaccines shows JUST that. medrxiv.org/content/10.110….

So, for the rest of us, what's the point of boosters? Preventing infections. Controlling transmission. If we CAN prevent infections in the most vulnerable populations, that’s a huge win and boosters seem to allow us to do just that. Prevention is key. medrxiv.org/content/10.110…

Some sources on boosters:
•On FEWER Myocarditis Cases: reuters.com/world/middle-e…
•LOWEST Rate of Side Effects after 3rd Dose: timesofisrael.com/3rd-dose-has-l…
•apple.news/Al9yV5ZhgQyyQR…
•theatlantic.com/ideas/archive/…
•theatlantic.com/health/archive…
•wsj.com/articles/when-…