Side effects of shingles vaccination may include a severe allergic reaction along with developing shingles, in the case of Zostavax.

What Is Shingles?

Shingles is a viral infection thought to be caused by a reactivation of the chickenpox virus. After individuals get chickenpox as children, the varicella zoster virus lies dormant in the central nervous system. Doctors are not certain what causes the virus to be reactivated, but it is thought that age and stress may play a role.

Once the virus is activated, pain is usually the first symptom to appear. Some patients may also develop a rash in the form of blisters. This rash usually only appears on one side of the body in a small section. It often wraps around the side of the torso, but can also occur around an eye or on one side of the face and neck.

Even though the infection is usually not life-threatening, shingles can cause severe complications, including:

• Postherpetic neuralgia (shingles pain that continues long after the rash has subsided due to damages nerves)
• Vision loss (if shingles occurs around the eye and causes an eye infection)
• Neurological problems
  • Encephalitis (inflammation of the brain)
  • Facial paralysis
  • Hearing problems
  • Balance problems
• Skin infections (if blisters from a shingles rash are not treated)

Is There a Shingles Vaccination?

There are two shingles vaccinations approved by the U.S. Food and Drug Administration (FDA). The older vaccine is called Zostavax and the newer vaccine is called Shingrix.

Zostavax contains a weakened but live version of the shingles virus, which can lead to an increased chance that the vaccine itself can cause shingles instead of preventing it. In contrast, Shingrix is a recombinant vaccine according to Healthline.

The Centers for Disease Control and Prevention (CDC) explains that Zostavax has been on the market since 2006, while Shingrex has only been used since 2017. Nonetheless, the newer vaccine is preferred. According to some critics, the makers of Zostavax should have been aware that vaccines that use a live, but weakened, virus (called an attenuated virus) can strengthen once a patient has been inoculated. Merck & Co., the makers of Zostavax, have faced lawsuits from patients, who say that the company put patients at a risk for infection through the vaccine. Allegedly, the varicella zoster virus is one that is likely to re-strengthen and put patients at risk for infection.

The benefit to patients who get a vaccine made with an attenuated virus is that if the vaccine works well, a patient’s immune response to the virus is strong, meaning they are better protected. 

Shingrex may provide some of the benefits of Zostavax, with less risk of concerning side effects of shingles vaccination, like a possible infection. It is a recombinant vaccine, which means that it’s made with specific pieces of the varicella zoster virus. Recombinant vaccines can use the protein, sugar, or capsid (germ’s casing), as opposed to the whole virus, explains vaccines.gov. In Shingrex, DNA from the shingles vaccine has been altered and purified in order to elicit an immune response that causes inoculation without the risk of developing the condition.

These vaccines can give patients a very strong immune response to a virus, but do not come with the risk that the virus could strengthen and fully infect the patient. Recombinant vaccines are particularly beneficial because they can be used on patients who might not be able to tolerate a live-attenuated vaccine, include those patients who are immunocompromised.

A downside of a recombinant vaccine is that it requires booster shots to ensure that a patient gets the vaccine’s full immune system benefit. 

Zostavax is reportedly 51 percent effective in preventing shingles and 67 percent effective in preventing postherpetic neuralgia. Shingrix is much more effective, reportedly up to 90 percent effective in preventing both shingles and postherpetic neuralgia.

Because Shingrix has been shown to be more effective, longer-lasting, and safer than Zostavax, it is the CDC’s preferred vaccine. The CDC recommends that individuals older than 50 get the Shingrix vaccination.

However, the CDC notes that individuals should not receive a shingles vaccine if any of the following criteria apply:

• They have severe allergies to vaccine components
• They are pregnant
• Their immune system is weakened by:
  • HIV/AIDS
  • Drugs that cause immune system changes
  • Cancers affecting the marrow of the lymphatic system
  • Cancer treatments such as chemotherapy or radiation

What Are the Side Effects of Shingles Vaccination?

Mild side effects of receiving a shingles vaccination may include injection site reactions including redness, swelling, itching, or soreness. A headache may also be possible.

A more serious side effect of the shingles vaccination is a life-threatening allergic reaction known as anaphylaxis. During anaphylaxis, the body floods itself with chemicals that cause shock and close the airways.

Symptoms of anaphylaxis may include swelling of the face, hives, warm/red skin, trouble breathing, dizziness, irregular heartbeat, and a rapid pulse. Anaphylaxis can be life-threatening, meaning that treatment is required immediately.

In some cases, getting the shingles vaccine can result in the development of shingles. This means that patients are exposed to the risk of any shingles complications including postherpetic neuralgia, vision loss, neurological problems, and skin infections.