Is the Shingles Vaccine an mRNA Vaccine?

Shingrix, the shingles vaccine recommended for adults 50 and older, is not an mRNA vaccine. It is a recombinant subunit vaccine, meaning it contains a lab-made copy of a single protein from the varicella-zoster virus paired with a chemical booster called an adjuvant. The confusion is understandable given the timing of Shingrix’s growing popularity alongside the rollout of COVID-19 mRNA vaccines, and the fact that both can cause noticeable short-term side effects. But the two technologies work in fundamentally different ways.

How Shingrix Works

Shingrix delivers a purified protein called glycoprotein E, which sits on the surface of the varicella-zoster virus (VZV), the same virus that causes chickenpox in childhood and shingles when it reactivates later in life. The vaccine does not contain any live virus, inactivated virus, or genetic material. It contains only a single protein made through recombinant DNA technology, meaning the protein is manufactured in a cell culture rather than harvested from the virus itself.¹

That protein alone would not produce a strong enough immune response, especially in the older adults who need shingles protection most. This is where the adjuvant system comes in. Shingrix uses an adjuvant called AS01B, which contains two immune-stimulating compounds: MPL (a detoxified bacterial lipid) and QS-21 (a plant-derived molecule). Together, these compounds ramp up the body’s immune response by activating antigen-presenting cells and boosting T-cell activity through a cascade that involves early production of interferon-gamma in the lymph nodes.² The adjuvant is a big part of why Shingrix works so well even in people whose immune systems have naturally weakened with age.

Why People Think It Might Be mRNA

Before 2020, most people had never heard of mRNA vaccine technology. The COVID-19 pandemic changed that virtually overnight. The Pfizer-BioNTech and Moderna vaccines became household names, and “mRNA vaccine” entered everyday conversation. Around that same period, health authorities were ramping up recommendations for Shingrix, which had been approved in 2017 but was still rolling out widely. Many adults were getting both vaccines in the same general timeframe, sometimes within months of each other.

The side-effect profiles added to the confusion. Both Shingrix and the COVID-19 mRNA vaccines are known for causing sore arms, fatigue, headaches, and muscle aches. If you got Shingrix and felt lousy for a day or two, it was easy to assume the vaccine must use the same technology as the COVID shot that produced similar symptoms. But that overlap in side effects comes from the immune system being strongly activated, not from the vaccines sharing a platform. Shingrix’s reactogenicity comes largely from its powerful AS01B adjuvant, while mRNA vaccines trigger a strong response through a completely different mechanism involving your own cells temporarily producing viral proteins.

There is also a simpler source of confusion: the word “recombinant.” It sounds technical and vaguely genetic, which can blur together with “mRNA” in casual understanding. But recombinant protein technology has been used in vaccines for decades. The hepatitis B vaccine, for instance, uses a recombinant protein approach that is conceptually similar to Shingrix. This is well-established, pre-mRNA technology.

The Key Difference Between the Two Approaches

In a subunit vaccine like Shingrix, the protein that trains your immune system is manufactured outside the body. Cells in a lab produce glycoprotein E, it gets purified, combined with the adjuvant, and injected as a finished product. Your immune cells encounter the protein directly and learn to recognize it.

An mRNA vaccine takes a different route. Instead of delivering the finished protein, it delivers genetic instructions (messenger RNA) wrapped in a tiny lipid shell. Once injected, your own cells read those instructions and produce the target protein themselves. The immune system then responds to that protein. The mRNA is temporary and breaks down within days. This approach was validated at massive scale with the COVID-19 vaccines and has since expanded to other targets, including respiratory syncytial virus and influenza.

Both approaches ultimately teach the immune system to recognize a specific viral protein. The difference is where that protein gets made: in a manufacturing facility (subunit) or inside your own cells (mRNA). For the shingles vaccine currently on the market, the answer is the manufacturing facility.

Side Effects Are Real but Temporary

One thing Shingrix and the COVID mRNA vaccines genuinely share is a reputation for noticeable side effects. Shingrix is among the more reactogenic vaccines in routine use. In pooled data from the two large trials that led to its approval, about 78% of Shingrix recipients reported injection-site pain, compared with about 11% in the placebo group. Muscle aches, fatigue, and headache each affected roughly 37% to 45% of vaccine recipients. Most symptoms were mild to moderate and lasted a median of two to three days.³

These side effects are driven mainly by the AS01B adjuvant doing its job. The whole point of AS01B is to provoke a vigorous immune response, and the cost of that vigor is a couple of uncomfortable days. The reactogenicity has been significant enough to affect real-world uptake. Some people skip the second dose, and some avoid the vaccine entirely after hearing about friends’ or family members’ experiences.⁴ That two-dose requirement itself is a compliance barrier: you need both shots, given two to six months apart, for full protection.

Researchers are actively working on next-generation shingles vaccines that might reduce these side effects while maintaining or improving efficacy. Some of those candidates, as it happens, are mRNA-based.

mRNA Shingles Vaccines Are Coming

While today’s shingles vaccine is not mRNA, tomorrow’s might be. Several research groups are developing mRNA-based shingles vaccine candidates that encode the same glycoprotein E target used in Shingrix but deliver it through the mRNA platform instead of as a preformed protein with adjuvant.

One candidate called CVG206, tested in mice, showed that a 5-microgram dose produced antibody levels comparable to Shingrix, while higher doses of 10 and 20 micrograms generated substantially stronger antibody responses. The higher-dose groups also showed more robust T-cell activation, with greater production of key immune signaling molecules.⁵ These are early-stage animal results, not proof that an mRNA shingles vaccine will outperform Shingrix in people, but the direction is promising.

Other teams are working on optimizing the mRNA sequence itself. One approach used a combination of signal peptide replacement, modifications to the protein’s tail end, and stabilizing elements within the mRNA to boost the immune response. In testing across adult mice, aged mice, and mice with weakened immune systems, the optimized mRNA vaccine showed strong improvements in antibody production, memory B-cell responses, and the type of T-cell activity most relevant to fighting reactivated VZV.⁶ Still another group has used artificial intelligence to screen large numbers of antigen designs before moving the most promising candidates into animal testing.⁷

The appeal of an mRNA shingles vaccine is partly about manufacturing (mRNA vaccines can be produced quickly and scaled up without complex protein purification) and partly about the possibility of achieving strong immune responses without the potent adjuvant that makes Shingrix’s side effects so noticeable. Whether any of these candidates will reach human trials and eventually replace Shingrix remains to be seen, but the pipeline is active.

The Older Shingles Vaccine Was a Different Technology Entirely

Before Shingrix, the only shingles vaccine available was Zostavax, a live attenuated vaccine that contained a weakened but still living version of VZV. Zostavax was the first vaccine to demonstrate that you could prevent shingles through vaccination, but it had significant limitations. Its efficacy was moderate and declined with age, and because it contained live virus, it could not be given to people with compromised immune systems, the very population at highest risk for severe shingles.⁸

Shingrix solved both problems. Because it contains no live virus, only a purified protein plus adjuvant, it is safe for immunocompromised patients. And its efficacy in clinical trials exceeded 90% even in adults over 70, a dramatic improvement over Zostavax’s performance in the same age group. Zostavax was discontinued in the United States in 2020, and Shingrix is now the only shingles vaccine available in most countries.

So the trajectory of shingles vaccination has already moved through two distinct technologies: live attenuated virus (Zostavax) and then recombinant subunit protein with adjuvant (Shingrix). If an mRNA candidate eventually reaches the market, it would represent a third technology generation for the same disease.

Why Shingles Matters Enough to Vaccinate Against

Shingles occurs when VZV, the virus that caused your childhood chickenpox, reactivates after lying dormant in nerve cells for decades. The virus hides in clusters of nerve cell bodies called ganglia, particularly in the trigeminal ganglia near the face and the dorsal root ganglia along the spine.⁹ When it reactivates, it travels along a nerve fiber to the skin, causing a painful, blistering rash that typically appears in a band on one side of the body.

The rash itself is unpleasant, but the bigger concern is postherpetic neuralgia, a condition in which the nerve pain persists for months or even years after the rash has healed. Postherpetic neuralgia can be debilitating, and it becomes more likely as you get older. Roughly one in three people will develop shingles at some point in their lives, and the risk climbs sharply after 50. The immune system’s natural ability to keep VZV dormant weakens with age, which is exactly why the vaccine targets older adults.

Shingrix’s strong adjuvant is specifically designed to overcome this age-related immune decline. The AS01B system produces robust antibody and CD4+ T-cell responses even in older and immunocompromised populations, which are exactly the groups where the immune system most needs a boost to keep VZV in check.¹ That performance in the age groups that need it most is a major reason Shingrix has been so widely adopted despite its reputation for side effects.

What to Tell Someone Who Asks

If a friend or family member is hesitating about Shingrix because they are worried about mRNA technology, the straightforward answer is that it does not use mRNA. It is a protein-based vaccine with decades of underlying science behind its platform. The protein-plus-adjuvant approach is not experimental and has been in clinical use for other diseases long before mRNA vaccines entered the picture.

If someone is hesitating because of the side effects, that is a more legitimate concern to talk through. The short-term reactogenicity is real and well-documented, and it is worth being prepared for a rough day or two after each dose. But those temporary side effects are a sign of a strong immune response, and they typically resolve within 72 hours. The alternative, a shingles episode that can last weeks and potentially leave lasting nerve pain, is a meaningfully worse outcome.

And if someone is curious about whether an mRNA version will eventually become available, the honest answer is that it is plausible but not imminent. Multiple mRNA shingles candidates are in preclinical development, with some showing strong results in animal models. But the gap between promising mouse data and an approved human vaccine is wide, often spanning many years. For now and for the foreseeable future, the shingles vaccine you can actually get is a protein subunit vaccine, not an mRNA one.

Keeping Vaccine Technologies Straight

The COVID-19 pandemic introduced a lot of vaccine terminology into public awareness all at once, and it is worth keeping the main categories distinct. Live attenuated vaccines use a weakened version of the actual pathogen; the measles-mumps-rubella vaccine is the classic example, and the old Zostavax fell into this category. Inactivated vaccines use a killed version of the pathogen; some flu shots and the polio vaccine work this way. Subunit or recombinant vaccines, the category Shingrix belongs to, deliver just one or a few purified proteins from the pathogen. Viral vector vaccines use a harmless carrier virus to deliver genetic instructions; the Johnson & Johnson COVID vaccine was this type. And mRNA vaccines deliver genetic instructions directly in lipid nanoparticles; the Pfizer and Moderna COVID vaccines pioneered this approach at scale.

Each platform has its own advantages and trade-offs in terms of how quickly it can be developed, how it needs to be stored, how strong an immune response it generates, and what kinds of side effects it tends to produce. The shingles vaccine conversation sits firmly in the subunit/recombinant camp. The mRNA chapter for shingles has not been written yet, though researchers are working on the opening pages.