Shingrix vs Zostavax: Differences Between Vaccines

Most, if not all, adults harbor in their bodies the varicella-zoster virus that causes childhood chickenpox. But long after chickenpox is gone, the virus stays dormant in the body. It can reactivate later and cause herpes zoster, more commonly known as shingles.

While there's no cure for shingles, you can prevent it through vaccination. Shingrix and Zostavax are the two vaccines for this disease, although the latter is no longer available in the US as of November 2020. The vaccines differ in effectiveness, administration, and side effects. So, which one is better? Read on to find out!

How many shingles vaccines are there?

One in every three Americans will suffer from shingles in their lifetime, and the risk increases with age. While there's no cure for shingles, you can manage symptoms through medication and at-home care.¹

But the symptoms can be painful and debilitating, and lack of proper treatment can lead to long-term complications such as:

• Postherpetic neuralgia (PHN)

• Vision loss (Herpes zoster ophthalmicus)

• Brain inflammation

• Ramsay Hunt Syndrome

Thus, the best way to manage shingles is through prevention. There are currently two vaccines for protecting against shingles: Shingrix and Zostavax (although Zostavax is no longer available in the US as of November 2020).

What is Zostavax?

Zostavax contains a live, weakened form of the varicella-zoster virus. When injected into the body, it produces an immune response that generates protection against shingles.

This vaccine is administered in a single dose underneath the skin (subcutaneous).

The vaccine has been intended for patients aged 50 and over. Research has shown that it can reduce the chances of having shingles by 70% and PHN by 67% for patients aged 50-59 years.²

Studies have also shown that the efficacy of the vaccination goes down with time, reaching 35% six years after vaccination. However, the protection is relatively unchanged for the first five years, and the duration of prevention of postherpetic neuralgia is thought to be preserved longer.³

What are the possible side effects of Zostavax?

Zostavax is generally well tolerated, with systemic side effects like fever or myalgia being rare. Like any other vaccine, the FDA monitors Zostavax for unusual or severe problems. No common serious problem has been identified yet, but you may experience mild side effects such as:

• Redness, soreness, swelling, or itching at the site of the injection

• Headache

As Zostavax is a live vaccine, there has been a single case report in the literature of a patient having developed latency with the vaccine-derived virus. Furthermore, six cases of acute retinal necrosis have also been reported.

Zostavax may also cause an allergic reaction in those allergic to gelatin or neomycin. Signs of an allergic reaction can include dizziness, difficulty breathing, hives, and weakness. These signs often appear a few minutes or hours after vaccination, so you should watch out for them.

Some people may develop a chickenpox-like rash near the vaccinated area. Ensure you cover the rash until it disappears as a precaution.

Being a live vaccine, Zostavax is not recommended for people with a weakened immune system. It's also not ideal if you're taking immunosuppressive agents. The suppressed immune system may be unable to fight off the live germ.

Zostavax discontinued

This vaccine is no longer available in the US as of November 18, 2020. While there was a lot of controversy surrounding Zostavax, the main reason for discontinuation was the vaccination platform.

Live vaccines are generally not preferred as they have a long list of contraindications. Additionally, protein-based/mRNA vaccines can elicit much narrower and higher-quality immune responses.

What is Shingrix?

Shingrix is a recombinant-designed vaccine. This vaccine doesn't contain the live varicella-zoster virus. Instead, it uses a specific protein of the zoster virus called glycoprotein E.

Your body will respond to this protein by producing antibodies to fight it off — this is also called an immune response.

Additionally, this vaccine contains an adjuvant that helps boost the body's immune response to the virus. In cases of future infections, the antibodies will bind to the germs and block them while alerting the rest of the immune system.

A vaccine that uses the recombinant design usually needs multiple shots to get maximum protection against the target germ. Shingrix is a two-injection vaccination administered into the muscle (intramuscular). 

The second dose is vital to ensure long-term effectiveness, and you should get it 2–6 months after the first dose. However, immunocompromised patients may benefit from an accelerated schedule, with the second dose delivered 1–2 months after the first. All in all, there should be a minimum of four weeks between the two doses.

Because Shingrix doesn't contain a live virus, it is safe for people with a deficient or compromised immune system.

This vaccine is recommended for persons over the age of 18. In fact, it has proven to be 90% effective at preventing shingles and 89% effective for PHN. Because Shingrix doesn't contain a live virus, it is also safe for adults over 18 with a weakened immune system.⁴

This group can benefit from the Shingrix vaccine as they are at a higher risk of developing shingles and related complications. 

Finally, protection derived from Shingrix appears durable in the long run, with a study demonstrating high efficacy at least seven years after vaccination.⁵

Are there any complications associated with Shingrix?

The CDC says that this vaccine is safe, but you may encounter mild side effects such as:

• Pain, redness, and swelling at the site of injection

• Headache

• Muscle pain

• Nausea

• Upset stomach

• Flu-like symptoms, including fever, shivering, and tiredness

Most of these symptoms will go away within a few days or weeks after the vaccination. If not, or if they become severe, talk to your doctor. Furthermore, adverse reactions are generally less severe after the second dose and less frequent in older patients.

Shingrix can also cause hypersensitivity or affect people with allergies to its ingredients. According to the FDA, this vaccine is associated with an increased risk of Guillain-Barré syndrome.⁶

Despite this rare nervous system disorder, the FDA affirms that the benefits of Shingrix far outweigh the negatives, as the increased risk is extremely low, i.e., three excess cases for a million doses administered. Furthermore, a secondary analysis of the data failed to elucidate any increased risk following the second dose of the vaccine.

What is the difference between the two shingles vaccines?

Now that you understand the two vaccines, let's highlight some key differences. Although these vaccines have not been compared head to head, the main difference between Shingrix and Zostavax is efficacy and durability. 

As mentioned earlier, the former is 90% effective at preventing shingles, while the latter only offers 70% protection in the comparable age group. Zostavax efficacy also reduces with time and as an individual gets older. At 70 years and over, Shingrix will provide 89% protection, while Zostavax offers 41%.

The Zostavax vaccine contains a live virus, which makes it unsafe for people with weakened immunity. On the other hand, Shingrix is safe for everyone, including 18-year-olds with compromised immunity.

Shingrix contains an adjuvant, which is an added ingredient that boosts immune response and the vaccine's effectiveness. 

The second difference is in administration. Zostavax is a one-injection vaccine, while Shingrix is given in two doses spaced at least four weeks apart. Shingrix is administered into a muscle, while Zostavax goes under the skin.

Shingrix vs. Zostavax: are there any similarities?

The biggest similarity is that they are both approved for preventing shingles. This means they can also prevent complications from shingles like postherpetic neuralgia (PHN).⁷

Remember that these vaccines are not for treating shingles, chickenpox, or PHN. If you currently have shingles, wait until you're recovered to receive the shingles vaccination. Antiviral drugs, such as acyclovir and famciclovir, may interfere with the effects of Zostavax.

Although both vaccines have the potential for severe reactions, most side effects are mild. They may only consist of a sore arm around the injected part.

Another similarity is that both vaccines are administered via an injection.

Who should get the shingles vaccine?

Shingles is the reactivation of the varicella-zoster virus. So, if you've ever had chickenpox, it would be best to get a shingles vaccine. Some people don't remember if they had chickenpox in childhood — it's better to err on the safe side by being vaccinated.

The risk of developing this infection increases with age. And scientists believe this is due to the age-related weakening of the immune system. The Advisory Committee for Immunization Practices (ACIP) currently (as of November 2022) recommends routine vaccination of immunocompetent adults over 50, as well as those over 18 who either are or will be immunodeficient or suppressed.⁸

You should get a shingles vaccine even if you've had shingles to prevent future infections. Just remember to do it after the rash has disappeared.

Some people should not get the shingles vaccine. This includes anyone with a life-threatening or severe allergic reaction to any vaccine component. Women who are pregnant or hoping to be pregnant in the next four weeks should wait before getting the shingles vaccine.

The lowdown

The Shingrix and Zostavax vaccines can help reduce the risk of shingles and related side effects. But while they have a common goal, they differ in some areas, as seen in this text.

Due to its greater effectiveness, the CDC recommends Shingrix over Zostavax. But if Shingrix is not available in your area or you're allergic to the Shingrix medicine, then Zostavax may be a viable option. For those in the US, Zostavax is no longer available.

Talk to your doctor for more information on these vaccines and possible side effects!

Frequently asked questions

There's so much more to know about Shingrix vs. Zostavax that we can't fit into a single text. But before we conclude, here are some more common questions people have about these two vaccines.

Should I get the new shingles vaccine if I had the old one?

Shingrix is considered more efficient than the Zostavax vaccine. In fact, the CDC recommends that people over the age of 50 should receive two doses of Shingrix. This should be done regardless of their immunization history with Zostavax.

Is Shingrix a live vaccine?

No, it's not. A live vaccine contains a weakened form of the virus, but Shingrix is a recombinant vaccine. It's made of parts of the shingles virus and includes an adjuvant to help boost the immune response. On the other hand, Zostavax contains a live, weakened virus.

How long does the shingles vaccine last?

According to the CDC, the Zostavax vaccine can prevent shingles for around seven years after vaccination. On the other hand, Shingrix remains highly effective for the first seven years after vaccination.

Keep in mind that the efficacy of Zostavax is lower from the beginning compared to Shingrix. Both vaccines become less effective with time. The CDC recommends both vaccines to people over 50, so they can have as much protection as possible in their vulnerable years.