mRNAvaccins

mRNA vaccines are a class of vaccines that use messenger RNA encoding a pathogen’s antigen, typically a surface protein, to elicit an immune response. Once delivered into host cells, the mRNA is translated by ribosomes to produce the antigen, which is then expressed or released, triggering humoral and cellular immunity. They do not contain live pathogen and do not alter a person’s DNA.

Delivery relies on lipid nanoparticles to protect the mRNA and facilitate entry into cells. The mRNA is often chemically modified to improve stability and reduce unwanted innate immune activation. Vaccines are designed to produce the specific antigen that the immune system should recognize, leading to antibodies and T cell responses that can neutralize real pathogens.

Prophylactic mRNA vaccines have been deployed widely, with the first major public use during the COVID-19 pandemic. Vaccines such as those targeting SARS-CoV-2 demonstrated high efficacy in preventing symptomatic disease and severe outcomes in trials and real-world studies. They have since been approved or authorized in many countries and are under evaluation or development for other infectious diseases and for cancer therapies.

Safety profiles show that most common side effects are transient and include injection-site pain, fatigue, headache, and muscle aches. Serious adverse events are rare. Anaphylaxis is possible but uncommon, and unusual long-term risks are not supported by available evidence. mRNA itself degrades rapidly and does not integrate into the genome, mitigating certain safety concerns.

Storage and distribution often require cold chain logistics, though newer formulations have improved stability, enabling longer storage at standard refrigerators for limited periods. Ongoing research aims to broaden protection to additional pathogens, enhance durability, and apply mRNA vaccine platforms to other diseases.