Shingrix May Prevent Shingles Better Than Zostavax, Despite Increased Injection Site Risks: Study

Amid growing concerns about the risk of Zostavax complications, new research suggests that the newer shingles vaccine Shingrix appears be more effective, although it may carry a higher risk of injection site problems. 

In a study published last week in The BMJ, Canadian researchers indicate that Shingrix is 85% more effective at preventing shingles than Zostavax. Although the newer vaccine has been linked to an increased risk complications at the injection site, it was no more safe than Zostavax when it came to serious adverse events and death.

Shingrix (recombinant zoster vaccine; RZV) is a GlaxoSmithKline shingles vaccine was just placed on the market in October 2017. It is approved for adults age 50 and older, and is one two shingle vaccines that are currently approved in the United States. The other is Merck’s Zostavax (zoster vaccine live; ZVL).

In this latest study, researchers looked at 27 studies involving more than 2 million patients, examining the incidence of shingles (herpes zoster), other shingles-related ailments, quality of life, adverse events, and death.

According to the findings, the Shingrix vaccine was more effective than Zostavax at preventing shingles. However, there were nearly 80% more injection site adverse events linked to Shingrix than Zostavax. However, there was no difference in major adverse events and deaths, the researchers noted.

“Using the adjuvant recombinant subunit vaccine might prevent more cases of herpes zoster than using the live attenuated vaccine, but the adjuvant recombinant subunit vaccine also carries a greater risk of adverse events at injection sites,” the researchers concluded.

The findings come several months after the U.S. Centers for Disease Control and Prevention (CDC) issued a warning highlighting the number of adverse event reports submitted in recent months involving Shingrix administration errors, which resulted in injection site problems and other complications.

The report indicated that 155 reports were submitted to the Vaccine Adverse Event Reporting System during the first four months Shingrix was available, including at least 13 problems with Shingrix administration. According to the findings, nine of those errors were because the drug was administered in a single subcutaneous dose, instead of as a 2-dose intramuscular injection, which is how the vaccine should be given. The single subcutaneous dose is how Zostavax is administered, suggesting confusion among doctors.

All but one of those patients suffered injection site reactions, including pain, erythema, and pruritus.

The study also comes amid growing reports about cases of very severe and persistent shingles outbreaks linked to Zostavax, which appears to be linked to the use of an “under-attenuated” live virus.

Merck faces a growing number of  Zostavax lawsuits filed throughout the U.S., each alleging that the drug maker failed to warn the medical community or patients of the risk that the vaccine could cause persistent shingles and other viral infections. Given similar questions of fact and law, claims filed nationwide are centralized before U.S. District Judge Harvey Bartle III in the Eastern District of Pennsylvania as part of an MDL, or multidistrict litigation.