Higher antibody level does not mean greater ability to neutralize the virus. This Italian paper finds that the strongest neutralization activity was shown by a patient who had the lowest antibody level detected by conventional serology assays.
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onlinelibrary.wiley.com/doi/full/10.10…
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onlinelibrary.wiley.com/doi/full/10.10…
Some basics:
Neutralization is the ability of the antibodies to inhibit growth of the virus. This is measured by looking at virus growth in lab cells, while bathed with serum containing antibodies - typically from those who are either recovered (convalescent) or vaccinated.
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Neutralization is the ability of the antibodies to inhibit growth of the virus. This is measured by looking at virus growth in lab cells, while bathed with serum containing antibodies - typically from those who are either recovered (convalescent) or vaccinated.
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Antibody titer, on the other hand, is measured by commercially available assays such as ELISA or CLIA .
Low levels might be marked as negative if below the detection limit of the assay. Manufacturer's claim of accuracy for these is often higher than real-life experience.
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Low levels might be marked as negative if below the detection limit of the assay. Manufacturer's claim of accuracy for these is often higher than real-life experience.
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The study found that a higher antibody level in a patient's serum by serology assay did not correlate with the ability of the same serum to neutralise the virus.
This means that someone could have high antibody levels, but without much use in preventing virus infection.
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This means that someone could have high antibody levels, but without much use in preventing virus infection.
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In other words, not all of the antibodies (spike/other) that are measured in the serology assay are of the neutralising type.
To give a metaphor, imagine a large orchestra playing papa kehte hain. There may be 50 members in the team. But how many people do we really hear?
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To give a metaphor, imagine a large orchestra playing papa kehte hain. There may be 50 members in the team. But how many people do we really hear?
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Most of the music we hear will come from the lead singer, drummer, trumpet player and the guitarist. These are the mainstay of the orchestra - who can perform the song even without the rest if need be. They are the neutralizing antibodies.
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While serological assays can only look at the whole orchestra of 50 people, neutralizing antibodies are the 4 key players whose work really matters.
The size of the orchestra (total antibody level) need not matter, it is what we hear (the neutralization) that counts.
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The size of the orchestra (total antibody level) need not matter, it is what we hear (the neutralization) that counts.
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Summary:
A person with "low or undetectable" antibody levels post vaccination (or natural infection) could well be protected against the virus; we just won't be able to measure it with existing commercially available assays.
Quality>Quantity.
(See my tweet earlier today)
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A person with "low or undetectable" antibody levels post vaccination (or natural infection) could well be protected against the virus; we just won't be able to measure it with existing commercially available assays.
Quality>Quantity.
(See my tweet earlier today)
8/8
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