Only a handful of mRNA vaccines have reached full regulatory approval anywhere in the world, but the pipeline stretches into dozens of candidates spanning infectious diseases, cancer, and even veterinary medicine. As of mid-2025, three conventional mRNA vaccines hold major regulatory authorizations: two for COVID-19 and one for respiratory syncytial virus (RSV). A fourth product, a self-amplifying RNA vaccine, cleared approval in Japan in late 2023, pushing the technology into new territory. Beyond those, clinical trials are testing mRNA-based vaccines against influenza, Zika, HIV, and several cancers, while researchers work on fixes for the platform’s biggest practical limitation: the need for deep-cold storage.
The Approved mRNA Vaccines
The two COVID-19 mRNA vaccines that most people know remain the backbone of the approved list. Comirnaty, developed by Pfizer and BioNTech (known in trials as BNT162b2), became the first mRNA vaccine to receive emergency authorization in the United Kingdom in early December 2020, followed quickly by the United States, Canada, the European Union, and several other countries.1PubMed Central. BNT162b2 mRNA COVID-19 Vaccine: First Approval Moderna’s Spikevax (mRNA-1273) followed closely behind. Both have since been updated multiple times to match circulating SARS-CoV-2 variants and remain authorized across the EU, the US, and many other jurisdictions.2PubMed Central. Overview of approved COVID-19 vaccines in the EU, recommendations for use in Sweden and vaccine uptake over time
The third approved conventional mRNA vaccine is Moderna’s mRESVIA (mRNA-1345), which targets RSV in older adults. In its pivotal trial, the vaccine showed roughly 84% efficacy against RSV-associated lower respiratory tract disease with at least two symptoms, and about 68% efficacy against RSV-associated acute respiratory disease more broadly. Side effects were mostly mild and short-lived, with serious adverse events occurring at the same rate in the vaccine and placebo groups.3PubMed. Efficacy and Safety of an mRNA-Based RSV PreF Vaccine in Older Adults The FDA granted approval in 2024, making mRESVIA the first mRNA vaccine approved for a disease other than COVID-19. That milestone matters because it signals regulators are comfortable extending the platform beyond the pandemic context that launched it.
Self-Amplifying RNA Breaks Through in Japan
In November 2023, Japan approved ARCT-154, a self-amplifying RNA (saRNA) COVID-19 vaccine developed by Arcturus Therapeutics. This makes it the first saRNA vaccine approved anywhere in the world.4PubMed. Self-amplifying RNA COVID-19 vaccine The distinction between conventional mRNA and saRNA matters practically. A standard mRNA vaccine delivers a fixed set of instructions that the cell reads once and discards. A self-amplifying RNA vaccine includes extra genetic machinery that lets the cell copy those instructions internally, producing more of the target protein from a smaller initial dose. In trials, ARCT-154 showed comparable safety and efficacy to BNT162b2 while using a lower dose of RNA material.4PubMed. Self-amplifying RNA COVID-19 vaccine
The lower-dose advantage could become important at scale. Less RNA per dose means manufacturing facilities can produce more doses from the same batch of material. Whether saRNA vaccines gain traction outside Japan remains to be seen, but the regulatory precedent now exists for this next-generation version of the platform.
The Influenza Pipeline
Flu is arguably the highest-profile target for the next wave of mRNA approvals, and multiple candidates are moving through clinical trials. Moderna’s mRNA-1010, a quadrivalent vaccine covering four flu strains, has been compared head-to-head against FLUAD, a licensed adjuvanted flu vaccine, in a randomized phase 1 trial. The results showed that a single dose of mRNA-1010 produced antibody levels and immune memory cell responses comparable to FLUAD across four flu strains over a full year of follow-up. For one strain (H3N2), the mRNA vaccine actually generated a stronger memory B cell response.5npj Vaccines. An mRNA influenza vaccine induces immunity comparable to an adjuvanted vaccine in a randomized trial
Separate early-stage work on a monovalent influenza mRNA vaccine (targeting H1N1 specifically) found dose-dependent immune responses that were numerically higher than those seen with a standard high-dose flu shot, and these elevated antibody levels persisted above baseline at six months. The vaccine also provoked a stronger T-cell response than the comparator, which is relevant because T cells help the immune system handle strains that drift away from the original vaccine target.6PubMed Central. Safety and immunogenicity of an investigational mRNA-lipid nanoparticle-based monovalent influenza vaccine: Results from a phase 1, randomized, dose-escalation study
One of the more ambitious flu-related projects is a combination vaccine that bundles COVID-19 and flu into a single shot. Early data suggest this approach has had mixed results: while the COVID component appears to hold up well, flu protection from the combination has not yet matched standalone flu vaccines in some trial arms.7JAMA. Combo COVID-19 and Flu mRNA Vaccine Falls Short of Total Flu Protection Getting the balance right in a combination product is a known challenge, and further development continues.
Zika, HIV, and Other Infectious Disease Targets
Beyond flu, mRNA vaccine candidates are in trials against a range of pathogens that have long frustrated vaccine developers. Moderna’s mRNA-1893, targeting Zika virus, completed phase 1 trials showing strong neutralizing antibody responses after two doses, regardless of whether participants had prior exposure to related viruses like dengue. The vaccine was well tolerated at all dose levels tested.8PubMed. The safety and immunogenicity of two Zika virus mRNA vaccine candidates in healthy flavivirus baseline seropositive and seronegative adults: the results of two randomised, placebo-controlled, dose-ranging, phase 1 clinical trials The fact that the vaccine works even in people with prior flavivirus exposure matters because antibody cross-reactivity between related viruses has been a major obstacle for Zika vaccine development.9PubMed Central. Current Advances in Zika Vaccine Development
HIV represents perhaps the hardest vaccine target in infectious disease, and mRNA is being explored there too. A phase 1 trial (HVTN 302) tested an mRNA vaccine encoding an HIV-1 protein trimer at two dose levels. The trial did produce immune responses, but it also flagged a safety concern: a notable proportion of participants developed chronic urticaria, a persistent hives-like reaction. Researchers are now investigating the mechanism behind these reactions before advancing the work further.10PubMed Central. High Frequency of Chronic Urticaria Following an Investigational HIV-1 BG505 MD39.3 Trimer mRNA Vaccine in a Phase 1, Randomized, Open-Label Clinical Trial (HVTN 302) That result is a healthy reminder that the mRNA platform is not automatically safe for every antigen; the protein encoded by the vaccine matters as much as the delivery vehicle.
Tuberculosis and malaria are also being explored as mRNA vaccine targets, though candidates for these diseases remain in earlier stages. The appeal is that mRNA vaccines can be designed and manufactured faster than traditional protein-based or live-attenuated vaccines, which is valuable for diseases where decades of conventional vaccine development have stalled.11PubMed Central. mRNA vaccines: a new opportunity for malaria, tuberculosis and HIV
mRNA Cancer Vaccines in Clinical Trials
The cancer vaccine pipeline is where mRNA technology looks most different from its infectious disease applications. Rather than preventing infection, these vaccines are designed to train the immune system to attack tumor cells. Two main approaches are being tested: personalized vaccines tailored to mutations unique to an individual patient’s tumor, and “off-the-shelf” vaccines targeting shared antigens found across many patients with the same cancer type.
BioNTech’s FixVac platform is the most developed example of the shared-antigen approach. BNT111, which encodes four melanoma-associated antigens, has completed a phase 1 trial in patients with advanced melanoma. Over three-quarters of patients developed immune responses against at least one of the targeted antigens. Among those who received BNT111 alongside standard anti-PD-1 immunotherapy, about a third had a partial response to treatment. A randomized phase 2 trial is now evaluating BNT111 alone and in combination with the checkpoint inhibitor cemiplimab in patients whose melanoma has stopped responding to standard immunotherapy.12The Lancet Oncology. Therapeutic mRNA cancer vaccines
The FixVac concept has expanded well beyond melanoma. Active clinical trials are testing mRNA cancer vaccines for prostate cancer (BNT112, encoding five tumor antigens), ovarian cancer (BNT115, encoding three ovarian-specific antigens), HPV-positive head and neck cancer (BNT113), and non-small cell lung cancer (BNT116).12The Lancet Oncology. Therapeutic mRNA cancer vaccines Each of these is in phase 1 or 2 testing, meaning they are being evaluated for safety and early signals of activity. None are close to approval yet, and the history of cancer vaccines is littered with candidates that looked promising early but failed in larger trials.
A separate line of research is testing mRNA vaccines that encode shared neoantigens derived from common cancer-driving mutations, rather than antigens specific to one cancer type. A phase 1 trial has been evaluating a vaccine encoding 20 such neoantigens in patients with advanced or metastatic solid tumors of various kinds.13Nature Medicine. A shared neoantigen vaccine combined with immune checkpoint blockade for advanced metastatic solid tumors: phase 1 trial interim results If this approach works, it could sidestep the manufacturing challenge of fully personalized vaccines, where each patient’s tumor has to be sequenced and a custom product made from scratch.
Solving the Cold Chain Problem
One of the biggest practical barriers to mRNA vaccine deployment has been their fragility. The Pfizer COVID vaccine famously required storage at roughly minus 70 degrees Celsius initially, which made distribution in low-resource settings extremely difficult. Even Moderna’s vaccine needed standard freezer temperatures. The underlying problem is that mRNA molecules and the lipid nanoparticles that carry them degrade rapidly in liquid form at warmer temperatures.
Freeze-drying (lyophilization) is emerging as the most promising fix. By converting the liquid vaccine into a dry powder, researchers have shown that mRNA vaccines can maintain their physical properties and immune-stimulating ability for far longer and at much higher temperatures. In one study, freeze-dried mRNA vaccines stored at room temperature for six months retained their particle size, RNA integrity, and produced antibody responses comparable to freshly prepared vaccines. Even at 40 degrees Celsius, the RNA integrity remained above 75% after 60 days.14Cell Discovery. Lyophilized mRNA-lipid nanoparticle vaccines with long-term stability and high antigenicity against SARS-CoV-2
Other research has confirmed these findings: freeze-dried mRNA vaccines have maintained stable properties for at least 12 weeks at room temperature and at least 24 weeks at refrigerator temperature, with no loss of immunogenicity in animal studies.15Molecular Therapy. Lyophilization provides long-term stability for a lipid nanoparticle-formulated, nucleoside-modified mRNA vaccine Moving from minus-70-degree freezers to a standard refrigerator or even room-temperature shelf would be transformative for global access, particularly for vaccines targeting diseases like malaria and tuberculosis that disproportionately affect tropical regions with limited cold-chain infrastructure.16PubMed Central. Freeze-Drying of mRNA-LNPs Vaccines: A Review
Intranasal and Other Delivery Routes
All currently approved mRNA vaccines are delivered by intramuscular injection, but that is not the only route being explored. Intranasal mRNA vaccines, still in preclinical and early clinical development, aim to stimulate immune responses directly at the mucosal surfaces where most respiratory pathogens first enter the body. The idea is that a nasal spray could trigger the production of secretory IgA antibodies and resident memory T cells in the nose and lungs, providing a first line of defense that injected vaccines cannot easily replicate.17PubMed Central. Intranasal mRNA vaccines: Targeting mucosal immunity through optimized delivery
The technical challenge is significant. Mucosal surfaces are designed to break down and expel foreign material, which is exactly what makes them a barrier to pathogens but also to vaccine delivery. Getting fragile mRNA molecules through that defense layer intact requires specialized formulations. No intranasal mRNA vaccine is close to approval, but if the approach succeeds, it could change the calculus for respiratory disease vaccines by adding mucosal protection on top of the systemic immunity that current shots provide.
Safety Monitoring After Approval
Post-authorization safety monitoring of the COVID-19 mRNA vaccines has been among the most intensive in vaccine history, and the data paint a mostly reassuring but not entirely clean picture. The most scrutinized signal has been myocarditis, or inflammation of the heart muscle, occurring primarily in young men after the second dose. An Australian surveillance study that followed people diagnosed with post-vaccination myocarditis found that about 60% still reported symptoms like chest pain, palpitations, or shortness of breath at the three-to-six-month mark. By 12 to 18 months, that proportion had dropped to about 35%, but those with ongoing symptoms were significantly more likely to still be on medication and have physical activity restrictions.18PubMed Central. Surveillance and follow up outcomes of myocarditis after mRNA COVID-19 vaccination in Australia
The overall rate of myocarditis after mRNA vaccination is low, and the condition is generally milder and resolves faster than myocarditis caused by viral infections. But the Australian follow-up data suggest that for the minority who are affected, recovery is not always as quick as early reports hoped. This ongoing monitoring feeds directly into how regulators make age-specific and dose-specific recommendations for boosters.
Next-Generation COVID Vaccines and Cost Considerations
Even within COVID, the vaccine landscape continues to evolve. Moderna’s mRNA-1283, a next-generation COVID vaccine, has been modeled against the current options. A cost-effectiveness analysis projected that, compared to Moderna’s existing Spikevax, mRNA-1283 would prevent an additional roughly 427,000 symptomatic infections, 36,000 hospitalizations, and nearly 5,000 deaths in the target US population, while also reducing overall healthcare costs. Against Pfizer’s Comirnaty, the projected advantages were even larger, with about 607,000 additional infections and 6,000 additional deaths averted.19medRxiv. Modeling the Cost-Effectiveness of the Next-Generation COVID-19 mRNA-1283 vaccine in the United States These are modeled estimates, not observed outcomes from a completed trial, so they should be interpreted as projections about what the vaccine could deliver based on its immunogenicity profile. But they illustrate that the platform is not standing still even for COVID.
The Patent Thicket
One underappreciated factor shaping the mRNA vaccine landscape is intellectual property. The patent environment around mRNA technology has become dense and tangled, with overlapping rights covering lipid nanoparticle formulations, modified nucleosides, manufacturing processes, and delivery methods. Multiple active lawsuits involve key components of the platform, and the outcomes could affect which companies can bring new mRNA vaccines to market and at what cost.20Journal of Intellectual Property Law & Practice. When mRNA technology meets patent law: innovation, barriers and public health
This matters beyond the courtroom. If developers need to license technology from multiple patent holders to make a single vaccine, costs go up and timelines stretch. For diseases primarily affecting low-income countries, like malaria or tuberculosis, a complicated patent landscape can be the difference between a vaccine that gets developed and one that does not. Efforts to navigate this tangle, through voluntary licensing agreements, patent pools, or simply waiting for key patents to expire, will shape how broadly the mRNA platform spreads in the coming decade.
Veterinary and Universal Vaccine Ambitions
The reach of mRNA vaccine research extends beyond human medicine. Researchers are exploring mRNA vaccines for livestock, particularly ruminants like cattle and sheep, where diseases such as foot-and-mouth disease and bovine respiratory disease cause enormous economic losses. The literature suggests that while mRNA vaccines show theoretical promise for veterinary applications, practical hurdles remain: the immune systems of ruminants differ from those of humans and standard lab animals, and cold-chain requirements are even harder to manage on farms than in clinics.21PubMed Central. Can the Revolution in mRNA-Based Vaccine Technologies Solve the Intractable Health Issues of Current Ruminant Production Systems?
At the other end of the ambition spectrum, researchers are pursuing universal vaccines that could protect against entire families of viruses rather than single strains. Early-phase clinical trials are testing mRNA-based candidates designed to generate immune responses against conserved regions shared across many influenza strains or many coronaviruses, rather than targeting the specific surface proteins that change from year to year.22PubMed. Beyond strain-specific immunity: Conserved antigenic targets, emerging platforms, and translational challenges in universal influenza and pan-coronavirus vaccine development If a pan-coronavirus or universal flu vaccine succeeds, it would represent a fundamental shift from the current model of annual reformulation and seasonal campaigns. The mRNA platform is well suited to this goal because encoding multiple antigens in a single construct is relatively straightforward compared to growing and inactivating multiple virus strains. Whether the immune system cooperates with that engineering ambition is the open question.