Shingrix: the New Vaccine for Shingles: Frequent Side Effects but High Effectiveness

(October 5, 2020)

Anyone who has had chickenpox (varicella zoster) is vulnerable to getting the painful rash called shingles. Once infected with chicken pox, the varicella virus remains dormant in the nerve cell clusters along a person's spine. Years later, it can be reactivated and cause the painful rash and illness known as shingles.

Because the chickenpox vaccine was not available in the U.S. until 1995, it is estimated that 99% of adults over the age of 40 have had chickenpox. The risk of shingles and painful post-herpetic neuralgia (PHN) increases with age.
  2016-2020 Number of Flu Vaccines Distributed in Millions

Varicella zoster virus (source: RoyaltyFree Istockphoto)

The first shingles vaccine, Zostavax, was approved in 2006 but is no longer sold in the U.S. It may be available to patients until November 2020, when the last of the already-sold supplies expire. GlaxoSmithKline's Shingrix (recombinant zoster vaccine) was approved in October 2017 and is now the only vaccine option for adults 50 & older to prevent shingles and its complications. It is administered in two doses, with the second dose required 2-6 months after the first.

While Shingrix is highly effective (90% or more) at preventing shingles, it comes with more risk of side effects than a typical adult vaccine. In fact, it has by far the highest number of adverse event reports (29,000) for routine adult vaccines in the Vaccine Adverse Event Reporting System (VAERS) between November 2017 and July 2020. The vaccine with the second highest number of reports in that time frame is Prevnar-13 (for pneumococcal pneumonia) with 6,385 reports and ranking third is Fluzone High Dose with 3,969 reports.

What to expect from the vaccine: almost everyone (about 80%) gets a sore arm at the injection site, and about half experience fatigue (myalgia), according to the vaccine label. Other common side effects are fever, chills, and headache. Many health care providers advise their patients to get the shot on a Friday and to plan to have the weekend unscheduled in case they experience uncomfortable reactions. Also, taking an over-the-counter pain medicine such as ibuprofen or acetaminophen after getting Shingrix can help ease discomfort from side effects.

Highlights of Experiences Reported at AskaPatient

About 30% of patients gave the vaccine a highly favorable rating (a 4 or 5). Even those who rated it highly tended to report side effects, but they also advised that the side effects of the vaccine, which tend to not last more than a few days, are far better than enduring the pain, itching, and blisters that occur in a typical shingles outbreak.

On average, men have a better opinion of the vaccine, with an average rating of 3 (somewhat satisfied), while women rated it a 2.5 on average (less than satisfied). However, more women than men provided their experiences. The VAERS database also contains more reports for women than men. The reviews that mention whether a dose was the first or the second suggest that the second dose may be more likely to cause harsher side effects than the first dose.
 Patient Satisfaction with Shingrix Shingles Vaccine

Experiences with side effects from Shingrix reported by 219 people (as of October 6) to AskaPatient:
Shingrix causing joint or muscle aches (135 reports)
Shingrix causing Headache (88 reports)
Shingrix causing fever (76 reports)
Shingrix causing chills (48 reports)
Shingrix causing swelling (23 reports)
Shingrix causing rash (18 reports)

All patient reports for Shingrix. 219 reports as of October 6, 2020. Use the "filter results" button to narrow down results by age, symptoms, or other criteria.

Why are the reactions to this vaccine so severe? It could be due to the strength of the vaccine, which includes a component called the adjuvant. The adjuvant is the liquid substance, in this case called AS01B,  that is mixed with the powdered antigen component right before administration that is used to create a stronger immune response. Severe reactions should be reported to your doctor and/or to VAERS. Signs of anaphylaxis like swelling of the face, difficulty breathing, dizziness, or heart palpitations require immediate medical attention.

Here are the most common side effects reported during GSK's clinical trials involving more than 14,000 people taking the vaccine. Interestingly, when these side effects are divided out by clinical trials age group (age 50-59, 60-70 and 70 and over), the incidence of side effects was lower in subjects aged 70 years and older compared with those aged 50 to 69 years. Also, the majority of the reactions seen with SHINGRIX had a median duration of 2 to 3 days in the clinical study. However, based on reports received by the FDA since the launch of the vaccine, additional adverse events include decreased mobility of the injected arm which may persist for 1 or more weeks. Immune system disorders, hypersensitivity reactions (like hives or rash) were also reported.
Shingrix Clinical Trials Adverse Reactions

Sources and More Reading:
Risks, symptoms, treating, preventing shingles. Fact sheets.

Information on Zostavax, which was discontinued as of July 1.

Vaccine Adverse Event Reporting System (VAERS)

Adjuvants in Vaccines

Complete Vaccine label for Shingrix

Vaccine information sheet for Shingrix

Why do we need separate chickenpox and shingles vaccines? While shingles vaccine does not protect against chickenpox, the chickenpox vaccine does seem to provide some protection against shingles.

A common drug used to treat shingles is the antiviral Valtrex (generic acyclovir). Here are patient experiences:
Valtrex taken for shingles
Acyclovir taken for shingles