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:
- 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
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.