New language has been added to leading shingles vaccine Shingrix over concerns that the injection may be responsible for an increased risk of a rare neurological autoimmune disease known as GBS, or Guillain-Barré Syndrome.
GBS occurs when the patient’s immune system attacks their nerve cells. It is diagnosed just 3,000 to 6,000 times a year and has been linked as a side effect of other vaccines as well, including the vaccine developed in response to the H1N1 flu pandemic.
The FDA stands behind its finding that Shingrix is a safe vaccine and continues to encourage its use, even going so far as to say that the “available evidence is insufficient to establish a causal relationship.” GSK, the vaccine’s creator, has also said that it “remains confident in the favorable benefit-risk profile of Shingrix for the prevention of shingles.” The same statement reiterated that the corporation would work with the FDA and CDC to continue monitoring patients that have been given the vaccine.
The elevated risk was discovered in a study of over 3.5 million patient records. The patients had received the full course of the Shingrix vaccine from October 2017 to February of 2020. When compared to Merck’s shingles vaccine, the Shingrix numbers showed approximately three additional cases of GBS per million doses administered.
The Shingrix vaccine is given in two injections spaced six months apart. The findings indicate that all additional GBS occurrences were linked to the initial injection and that the second injection did not play a role in the patient’s risk of developing the disease.
Shingrix’s release was well-received by regulators, with the CDC publicly stating its preference of Shingrix over Merck’s Zostavax. While Zostavax provides only a 51% efficacy against the very condition it was created to fight, Shingrix took the market by storm when its efficacy proved to be in the neighborhood of 97%. The agency also stated that those who had previously received a Zostavax vaccination should go ahead and get vaccinated with Shingrix as well.