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New COVID Vaccine formula Shows long-Lasting Antibody Protection
What happened?
New research from Emory University, published in
Science and Translational Medicine
, demonstrates that the 2023-24 COVID-19 vaccine generates robust and durable antibody responses. The study, involving 24 participants, focused on the vaccine’s effectiveness against the XBB.1.5 Omicron variant. The US has seen over 1.2 million deaths attributed to COVID-19, making continued vaccine development crucial.
Key findings indicate that antibodies produced by the 2023-24 vaccine have a half-life exceeding 500 days – over 16 months – meaning at least 50% of the antibodies remain detectable for that duration post-vaccination.
key Findings & Immune Response
Researchers evaluated three key components of the immune response over a 6-month period:
- Memory B cells: Recognize previously encountered pathogens.
- Binding antibodies: Flag pathogens for destruction.
- Neutralizing antibodies: Prevent pathogen replication.
The study revealed the production of cross-reactive antibodies effective against both the original WA1 strain and the Omicron XBB.1.5 variant. this broad reactivity is a significant positive outcome.
Monovalent vs. Bivalent Vaccines: A Shift in Strategy
A notable aspect of the 2023-24 vaccine is its monovalent formulation. Unlike previous vaccines which were bivalent (containing two spike proteins targeting both the ancestral strain and newer variants), the 2023-24 vaccine focuses on a single spike protein specifically designed for the then-dominant Omicron XBB.1.5 variant.
This shift in strategy appears to have been successful, perhaps due to a phenomenon called immune imprinting.
What is Immune Imprinting?
Immune imprinting, also known as original antigenic sin, refers to the immune system’s tendency to preferentially recall and respond to the first strain of a virus it encounters. In the context of COVID-19, early exposure to the original WA1 strain can shape subsequent immune responses to new variants.
The researchers hypothesize that immune imprinting may have enhanced the effectiveness of the monovalent vaccine by focusing the immune response on the current dominant variant, rather than diluting it with a response to an older, less relevant strain.
Who is Affected?
This research has implications for
