Understanding the different technologies used to create vaccines, from traditional approaches to cutting-edge mRNA platforms.
Vaccine platforms refer to the underlying technology or method used to develop a vaccine. Different platforms offer various advantages and disadvantages in terms of development speed, manufacturing, efficacy, and storage requirements. Understanding these platforms helps contextualize how vaccines work and why some may be better suited for certain populations or diseases.
A vaccine that delivers messenger RNA into cells, instructing them to produce a target protein that triggers an immune response without using live virus.
The mRNA is encapsulated in lipid nanoparticles that protect it and enable entry into cells. Once inside, ribosomes read the mRNA instructions to produce the target protein, which is displayed on cell surfaces where immune cells recognize it and develop a response.
mRNA vaccines can be designed and manufactured rapidly once the target pathogen's genetic sequence is known. No pathogen or inactivated pathogen material is required in production. The platform can be adapted for new targets by changing the mRNA sequence.
Requires cold-chain storage and distribution due to mRNA instability. Typically requires two doses for primary series. Common side effects (fatigue, headache, injection site pain) are generally transient and more pronounced than with some older platforms. Long-term durability of protection is still being studied for some applications.
Examples: Pfizer-BioNTech (Comirnaty), Moderna (Spikevax) for COVID-19
A vaccine that uses a harmless, modified virus (the vector) to deliver genetic instructions for a target pathogen's protein into cells.
The vector virus enters cells and delivers DNA that instructs cells to produce the target protein. Immune cells recognize the protein and develop antibodies and T-cell responses. Replication-competent vectors can amplify the signal within the body, while replication-incompetent vectors cannot.
The platform is well-established for other applications including cancer research and gene therapy. Strong immune responses can be achieved, including T-cell responses important for some pathogens. Some viral vectors can be designed for single-dose regimens.
Pre-existing immunity to the vector virus (common for adenoviruses) can reduce vaccine efficacy. Production is complex and scaling can be challenging. Some platforms require two doses. Very rare cases of vector integration into host DNA have been documented with certain vector types.
Examples: Johnson & Johnson (Janssen), AstraZeneca COVID-19 vaccines; Ebola vaccine
A vaccine containing purified pieces of the pathogen—typically proteins or polysaccharides—that are sufficient to trigger an immune response without containing live or killed pathogen material.
The purified antigens are presented to the immune system directly. Adjuvants are often included to enhance and shape the immune response. B cells recognize the antigens and produce antibodies; T cells provide supporting signals.
The platform has a long safety track record with no risk of infection or replication. Suitable for immunocompromised individuals who may not tolerate live vaccines. Storage requirements are generally less stringent than for newer platforms.
Immune responses may be weaker than with live attenuated vaccines and often require adjuvants and multiple doses. Identifying the correct antigen or antigen combination that produces optimal immunity takes research. Manufacturing can be complex for some antigens.
Examples: Novavax (COVID-19), Hepatitis B, HPV, Shingrix
A vaccine using a weakened (attenuated) form of the live virus or bacterium that can still replicate in the body but does not cause disease in healthy individuals.
The attenuated pathogen replicates in host cells, producing all native antigens in their natural form. This mimics natural infection without causing disease, generating a broad immune response including both antibodies and T-cell responses at mucosal sites when delivered intranasally.
Strong, broad, and typically long-lasting immunity is produced, often from a single dose. The immune response closely resembles natural infection. Some formulations are designed for mucosal delivery, triggering immunity at the site where many pathogens first enter the body.
Cannot be used in immunocompromised individuals or pregnant women due to the risk of disseminated infection in severely immunocompromised hosts. Requires refrigeration and has limited shelf life. In very rare cases, reversion to virulence has been documented. Production requires biosafety level facilities.
Examples: MMR, Varicella, Rotavirus, Nasal flu (FluMist), Oral polio (OPV)
A vaccine using a killed (inactivated) version of the whole virus or bacterium that cannot cause infection or replicate but retains enough structure to trigger an immune response.
The inactivated pathogen's antigens are presented to the immune system intact. Because the pathogen cannot replicate, adjuvants are often included to boost the immune response. The response is primarily antibody-mediated, though T-cell responses also occur.
The killed pathogen format is well-characterized with extensive historical safety data. Suitable for individuals who cannot receive live vaccines, including immunocompromised patients and pregnant women. Production methods and regulatory pathways are well-established.
Multiple doses and booster shots are typically required to achieve and maintain protection. Duration of immunity may be shorter than with live attenuated vaccines. Cannot induce strong T-cell responses in some cases. Requires proper inactivation—failure of inactivation is a theoretical risk.
Examples: IPV (polio), Hepatitis A, Rabies, some flu vaccines
A vaccine containing non-infectious particles that structurally resemble viruses but contain no genetic material and cannot replicate.
VLPs present multiple copies of viral antigens in a repeating, virus-like structure that triggers strong B-cell activation. The multivalent presentation mimics natural viral structure, generating high-quality antibody responses. Adjuvants may be included to enhance the response.
No live or killed pathogen is used, eliminating infection risk. The virus-like structure produces strong antibody responses without adjuvants in some cases. Suitable for immunocompromised individuals. Production is independent of pathogen cultivation.
Manufacturing is complex and requires sophisticated facilities. Multiple doses are often needed. Cost per dose can be high compared to some older platforms. Optimal antigen display and formulation require significant development work.
Examples: HPV vaccines (Gardasil, Cervarix), Hepatitis E vaccine
A newer form of RNA vaccine where the injected genetic material can copy itself inside cells, potentially requiring a smaller initial dose than standard mRNA.
Like mRNA vaccines, saRNA delivers instructions for cells to produce a target protein. Unlike standard mRNA, saRNA includes a replicase gene that allows the RNA to amplify within the cell, producing more protein from less starting material.
May offer equivalent protection at lower doses, which could reduce manufacturing costs and expand global access. Under study for influenza, COVID-19, and other targets.
Still in clinical development for most applications. Reactogenicity (side effects from the self-amplifying process) is being studied. Long-term data is limited compared to conventional mRNA platforms.
Examples: Under development; not yet FDA/EMA approved as of 2025
Vaccines delivered through the nose or mouth rather than by injection, designed to trigger immune responses at mucosal surfaces where many respiratory pathogens first enter the body.
Targets mucosal-associated lymphoid tissue (MALT) to produce secretory IgA antibodies at the site of infection, in addition to systemic immunity triggered by the broader immune system.
May reduce transmission by blocking infection at the point of entry. Can simplify administration (no needles). FluMist (nasal flu vaccine) is the most established example. Nasal COVID-19 vaccines are in advanced trials.
Mucosal immunity can be shorter-lived than systemic immunity. Dosing standardization is more complex. Live attenuated nasal vaccines are not suitable for immunocompromised individuals.
Examples: FluMist (nasal flu vaccine), OPV (oral polio vaccine); nasal COVID-19 vaccines in development
A method of delivering vaccines through a small adhesive patch containing tiny dissolving needles, rather than a traditional injection.
Microneedles penetrate the outer skin layer and dissolve, releasing the vaccine antigen into the skin where immune cells are concentrated. The skin is highly immunogenic.
Can simplify distribution by eliminating cold chain requirements for some formulations. Enables self-administration. May reduce needle-related anxiety and waste. Under study for measles, influenza, and COVID-19.
Manufacturing at scale is still being developed. Dosing consistency across different skin types is under investigation. Not yet widely approved for routine use.
Examples: Under development; not yet widely approved as of 2025