Shingles, or herpes zoster, is an infection caused by the chicken pox virus, Varicella zoster. The Shingrix vaccine can help prevent shingles, but it can have some side effects. Most of these are minor and do not last long.

Adults who had chicken pox as children carry the dormant virus. The virus can reactivate to cause shingles in later life, but the vaccine can prevent this.

However, some people have concerns about potential dangers and whether shingles vaccines are effective.

One vaccine currently has Food and Drug Administration (FDA) approval for shingles, which is the recombinant zoster vaccine (Shingrix). Previously, a different zoster virus vaccine (Zostavax) was available. However, it has been discontinued.

This article provides information about the Shingrix vaccine and its possible adverse effects.

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A shingles vaccination can significantly reduce the risk of developing shingles and related complications, including postherpetic neuralgia (PHN), a common complication that involves long-term nerve pain.

Other complications of shingles can include:

  • Eye complications. Having shingles in or around the eye increases the risk of corneal ulcers, glaucoma, retinal necrosis, and partial or total vision loss.
  • Pneumonia. The shingles virus can spread to the internal organs, resulting in internal shingles. People can also develop pneumonia if the virus infects the lungs.
  • Encephalitis. If the shingles virus infects the brain, it can cause severe, life threatening inflammation. Encephalitis, or brain inflammation, can cause memory problems, loss of some motor functions, mood changes, epilepsy, and even death.

Pneumonia and encephalitis are rare complications of shingles.

A shingles vaccine may cause the following short-term side effects:

According to the CDC, these symptoms usually last 2–3 days.

In rare cases, a person may experience a severe allergic reaction — or anaphylaxis — after a shingles vaccination.

The CDC notes that only one or two out of every 1 million people who receive the Shingrix vaccine develop a severe allergic reaction.

Signs of a severe allergic reaction include:

  • low blood pressure
  • dizziness or lightheadedness
  • hives
  • stomach pain
  • vomiting
  • anxiety
  • breathing problems or wheezing
  • swelling of the face, lips, tongue, or uvula, which is a part of the throat

If a person suspects that they or someone nearby is experiencing anaphylaxis, they should seek emergency medical aid.

Anyone in the U.S. who has experienced a severe allergic reaction to the shingles vaccine can report this online using the Vaccine Adverse Event Reporting System or by calling 1-800-822-7967.

Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:

  • hives
  • swelling of the face or mouth
  • wheezing
  • fast, shallow breathing
  • a fast heart rate
  • clammy skin
  • anxiety or confusion
  • dizziness
  • vomiting
  • blue or white lips
  • fainting or loss of consciousness

If someone has these symptoms:

  1. Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
  2. Dial 911 or the number of the nearest emergency department.
  3. Lay the person down from a standing position. If they have vomited, turn them onto their side.
  4. Stay with them until the emergency services arrive.

Some people may need more than one epinephrine injection. If the symptoms do not improve in 5–15 minutes, or they come back, use a second pen if the person has one.

Shingrix is the only shingles vaccine that currently has approval from the FDA. Previously, another zoster virus vaccine (Zostavax) also had approval. However, this product has been discontinued.

According to the Centers for Disease Control and Prevention (CDC), Shingrix is over 90% effective at preventing shingles and PHN.

A person will have the Shingrix vaccine in two doses. The CDC recommends waiting 2–6 months between the first and second doses.

With some exceptions, adults over 50 should get this vaccine, even if they have already had shingles or a Zostavax vaccine in the past.

According to the CDC, research has shown that Shingrix is safe.

Some people experience short-term adverse effects, such as a fever, muscle aches, and headaches. However, these usually last only 2–3 days.

In rare cases, people have developed Guillain-Barré syndrome (GBS) after having the shingles vaccine. However, this can also happen after shingles. GBS is a severe nervous system disorder.

The FDA recommends Shingrix for people who have or are likely to have a weakened immune system due to a health condition or treatment. Having a weakened immune system increases a person’s risk of developing shingles.

It can happen with the following:

  • a medical condition that compromises the immune system, such as AIDS
  • cancer that affects the lymphatic system or bone marrow
  • cancer treatments, such as radiation or chemotherapy
  • medications that affect the immune system, such as steroids

However, a person with a weakened immune system should speak with their doctor about whether to have the vaccine and when.

According to the CDC, nearly 1 in 3 people in the U.S. will develop shingles, and approximately 10–18% of people who get shingles will develop PHN.

Older adults and people with weakened immune systems have a higher risk of developing shingles, according to the National Institutes of Health (NIH).

The CDC and FDA recommend that all adults ages 50 years and older have the shingles vaccine.

Adults should also have a shingles vaccine if they:

  • do not remember if they have had chicken pox
  • do not remember if they have ever had a shingles vaccine
  • have already received the Zostavax vaccine, now discontinued
  • have a history of shingles

The CDC now recommends the shingles vaccine for younger adults aged 19 and over who have a weakened immune system or are likely to have one, for example, due to a medical treatment.

A person should not have the vaccine:

  • during pregnancy
  • if they currently have shingles
  • if they have previously had a severe allergic reaction to any of the ingredients in the vaccine
  • in some cases, if they have a weakened immune system

A doctor can advise an individual on having the Shingrix vaccine.

People who test negative for the Varicella zoster virus can get the chicken pox vaccine instead.

Here are some questions people often ask about shingles immunization.

Which is better, Shingrix or Zostavax?

Zostavax was discontinued in November 2020. Shingrix is the only available option. However, it is more than 90% effective at preventing shingles and postherpetic neuralgia.

How long does the shingles vaccine last?

Immunity remains strong for at least 7 years after the vaccination in most cases.

Does Medicare cover Shingrix?

According to the CDC, Medicare Part D plans cover the shingles vaccine. However, depending on their plan, some people may need to contribute some payment or seek reimbursement later.

Medicare Part B does not cover the shingles vaccine.

Medicaid and insurance may cover the cost of Shingrix. A person should check with their insurance provider to see if it is covered.

The risk of shingles significantly increases with age. The FDA and CDC recommend that adults ages 50 years and older have the Shingrix vaccine. According to CDC, it is safe.

Some people may have side effects, which usually last 2–3 days. They include headache, fatigue, a fever, and a feeling of being generally unwell. There may also be pain and swelling at the injection site.

Experts recommend the Shingrix vaccine for people aged 50 and over and those aged over 18 who have or are at risk of developing a compromised immune system.