Summary
Lipid-encapsulated mRNA instructs host cells to make an antigen, inducing immunity without infection.
In depth
Nucleoside-modified mRNA in lipid nanoparticles is translated in cells to make, for example, the spike protein, inducing antibodies and T cells. Development took less than a year for COVID-19. Karikó and Weissman received the 2023 Nobel Prize.
Modified nucleosides reduce innate sensing so translation is efficient. The vaccine mRNA is short-lived and doesn't enter the nucleus or alter DNA. Storage requires cold chains.
Common mistake: mRNA vaccines do not change a person's genes.
mRNA is delivered in lipid nanoparticles that protect it and help cells take it up, then ribosomes make the antigen, which is presented on MHC and also secreted for B cells. The RNA contains modified nucleosides (N1-methylpseudouridine) discovered by Karikó and Weissman (Nobel Prize 2023), which reduce innate sensing and increase translation. The mRNA is degraded within days and does not enter the nucleus or alter DNA.
Advantages are speed of design (the Moderna sequence was designed in days), no need to grow virus, and strong T and B cell responses. Challenges include cold storage, reactogenicity and waning antibodies. Uses are expanding to influenza, RSV, cancer vaccines tailored to a patient's tumour, and protein replacement.
Example: both leading COVID-19 vaccines used mRNA and showed about 95 percent efficacy in initial trials.
Frequently asked questions
What is mRNA Vaccines?
Lipid-encapsulated mRNA instructs host cells to make an antigen, inducing immunity without infection.
Which area of biology covers mRNA Vaccines, and how advanced is it?
mRNA Vaccines is one of the 52 topics in Immunology & Disease. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Antigenic Variation, Vaccines, Active and Passive Immunity.
Can you give an example of mRNA Vaccines?
Storage at low temperature was needed initially.
What should I learn before mRNA Vaccines?
Work through the Beginner topics in Immunology & Disease first, such as Immune System, Viruses, Innate Immunity, then return to mRNA Vaccines. Advanced topics assume the Intermediate vocabulary.
What topics are related to mRNA Vaccines?
The closest topics to mRNA Vaccines are Antigenic Variation, Vaccines, Active and Passive Immunity, B Lymphocytes. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand mRNA Vaccines?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for mRNA Vaccines. To practise the whole of Immunology & Disease, use the Immunology & Disease quiz.
How is mRNA Vaccines different from Antigenic Variation?
mRNA Vaccines: Lipid-encapsulated mRNA instructs host cells to make an antigen, inducing immunity without infection. Antigenic Variation: Pathogens such as influenza and trypanosomes alter surface antigens to evade immunity. Read both side by side and note what each one explains.
What is a common mistake about mRNA Vaccines?
MRNA vaccines do not change a person's genes.
How should I study mRNA Vaccines step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Antigenic Variation and explain the difference aloud. Finally, take the Immunology & Disease quiz and come back to this page for any question you miss.