Science & Tech

Immune Imprinting

A slew of recent studies has revealed that an in-body phenomenon known as immune imprinting may be making new booster vaccines far less effective than expected for coronavirus infection.

What is Immune Imprinting?

  • Immune imprinting refers to the body’s tendency to repeat its immune response based on the first variant encountered.
  • When our body encounters a newer or slightly different variant of the same pathogen, it does so through infection or vaccination.
  • The phenomenon was first observed in 1947, when scientists noted that “people who had previously had flu, and were then vaccinated against the current circulating strain, produced antibodies against the first strain.
  • It was known as the “original antigenic sin” at the time, but it is now more commonly known as imprinting.

How imprinting works for immune system?

  • Imprinting serves as a database for the immune system, allowing it to respond more effectively to repeat infections.
  • When our bodies are first exposed to a virus, it produces memory B cells, which circulate in the bloodstream and quickly produce antibodies whenever the same strain of the virus infects us again.
  • The issue arises when the body encounters a similar, but not identical, variant of the virus.
  • In such cases, the immune system activates memory B cells rather than generating new B cells.
  • This results in cross-reactive antibodies, which bind to features found in both the old and new strains.

Are booster doses completely ineffective?

  • These cross-reactive antibodies provide some resistance to the new strain.
  • They are, however, not as effective as the ones produced by B cells when the body first encountered the virus.

How can immune imprinting be avoided?

  • Several ongoing studies are currently attempting to find a solution to imprinting.
  • Some scientists believe nasal vaccines may be more effective than injected vaccines in preventing infections.
  • Despite carrying some imprint of previous exposure, they believe the mucous membranes will provide stronger protection.
  • Researchers are also investigating whether spacing out coronavirus vaccine shots on an annual basis could help with imprinting.
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