Self-replicating mRNA Covid-19 vaccines

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Self-replicating mRNA Covid-19 vaccines

  • A self-amplifying mRNA vaccine has shown promising results against Covid-19 in ongoing phase 1/2/3 trials.
  • The vaccine, ARCT-154, has been developed by Arcturus Therapeutics Holdings, based in San Diego, California, and its trials are in progress in Vietnam.
  • It offered 95% protection against severe Covid-19 and death, and 55% against Covid infection, Arcturus said in a press release.

mRNA vaccines

  • mRNA vaccines tricks the body into producing some of the viral proteins itself.
  • They work by using mRNA, or messenger RNA, which is the molecule that essentially puts DNA instructions into action. Inside a cell, mRNA is used as a template to build a protein.

Functioning of mRNA Vaccines:

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  • To produce a mRNA vaccine, scientists produce a synthetic version of the mRNA that a virus uses to build its infectious proteins.
  • This mRNA is delivered into the human body, whose cells read it as instructions to build that viral protein, and therefore create some of the virus’s molecules themselves.
  • These proteins are solitary, so they do not assemble to form a virus.
  • The immune system then detects these viral proteins and starts to produce a defensive response to them.

Advantages of Using mRNA based Vaccines:

  • mRNA vaccines are considered safe as mRNA is non-infectious, non-integrating in nature, and degraded by standard cellular mechanisms.
  • They are highly efficacious because of their inherent capability of being translatable into the protein structure inside the cell cytoplasm.
  • Additionally, mRNA vaccines are fully synthetic and do not require a host for growth, e.g., eggs or bacteria. Therefore, they can be quickly manufactured inexpensively to ensure their "availability" and "accessibility" for mass vaccination on a sustainable basis.

mRNA vs Traditional Vaccine

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Other types of vaccines

  • Vector vaccine:
    • In this type of vaccine, genetic material from the COVID-19 virus is placed in a modified version of a different virus (viral vector).
    • When the viral vector gets into your cells, it delivers genetic material from the COVID-19 virus that gives your cells instructions to make copies of the S protein.
    • Once your cells display the S proteins on their surfaces, your immune system responds by creating antibodies and defensive white blood cells.
    • If you later become infected with the COVID-19 virus, the antibodies will fight the virus.
  • Protein subunit vaccine:
    • Subunit vaccines include only the parts of a virus that best stimulate your immune system.
    • This type of COVID-19 vaccine contains harmless S proteins.
    • Once your immune system recognizes the S proteins, it creates antibodies and defensive white blood cells.
    • If you later become infected with the COVID-19 virus, the antibodies will fight the virus.

Exam Track

Prelims Takeaway

  • mRNA vaccines
  • Traditional vaccines

Mains Track

Q. mRNA vaccines can prove to be a gamechanger in the way the vaccines are administered to patients. Comment.