CDC Evaluates Concerns of Guillain-Barré Syndrome Following RSV Vaccination

The CDC and FDA are conducting population-based surveillance to evaluate the risks for Guillain-Barré syndrome (GBS) and other adverse events among individuals 60 years and older who received Arexvy (GSK) or Abrysvo (Pfizer, Inc.) to prevent respiratory syncytial virus (RSV). The CDC noted that the results will aid guideline and recommendation development for the Advisory Committee on Immunization Practices (ACIP).¹

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The study authors noted that RSV infection can result in lower respiratory tract disease, hospitalization, and death among older individuals. Additionally, RSV infection is responsible for extensive rates of morbidity and mortality among this population. Data from the CDC provided that each year in the US, between 60,000 and 160,000 individuals aged 65 years and older are hospitalized due to RSV, causing 6000 to 10,000 deaths.² RSV season begins in the fall and hits its peak season in the winter months, although researchers noted that the 2022 to 2023 season experienced earlier and more intense cases compared with previous years.^2,3

The FDA granted approval to both Arexvy and Abrysvo in May of 2023 for adults aged 60 years and older. Following the approval, ACIP released recommendations in June 21, 2023, that suggested all adults 60 years and older should receive a single dose of either RSV vaccine. Despite the approvals, some reports did emerge suggesting safety concerns of developing GBS.¹

From August 4, 2023, to March 30, 2024, nearly 7.2 million individuals aged 60 years and older received the Arexvy RSV vaccine and 3.4 million received the Abrysvo vaccine, according to study authors.¹ The researchers included 16,220 individuals who received a vaccine in an active US surveillance system, known as V-safe, that registered individuals to complete web-based surveys and reports to the Vaccine Adverse Event Reporting System (VAERS) during the 6 weeks after vaccination. The CDC reviewed the data from May 2, 2023, through April 14, 2024.¹

The V-safe surveys were to be completed daily and included questions on local injection site and systemic reactions, along with other health-related symptoms. Following the V-safe report, individuals who experience symptoms are also required to complete the VAERS report that tracks adverse events from health care providers, manufacturers, and patients.¹

“Symptoms and health impacts reported during the week after RSV vaccination were described for V-safe participants aged ≥60 years who were vaccinated during May 3, 2023–April 14, 2024, and completed one or more daily surveys. Primary VAERS adverse event reports after RSV vaccination for persons aged ≥60 years were described by serious and nonserious classification and MedDRA PTs,” said study authors, in a news release.¹

The results from the V-safe surveillance showed that infection site and systemic reactions occurred more among individuals who received Arexvy, compared with individuals who received Abrysvo. The study authors noted that the most reported vaccine reactions included pain in extremity, headache, and fatigue, all of which were mild. The VAERS data showed that there were 1.5 reports of GBS per million doses of both vaccines among individuals aged 60 years and older.¹

According to the study authors, the report included some limitations, beginning with a lack of representation of the vaccinated population in V-safe, because it was voluntary. The VAERS surveillance system could include incomplete data reporting of nonserious events and cannot decipher underlying adverse events and those from the vaccination. Lastly, the data do not compare the risks of GBS among unvaccinated individuals, compared with individuals that received an RSV vaccination.¹

References

1. Early Safety Findings Among Persons Aged ≥60 Years Who Received a Respiratory Syncytial Virus Vaccine — United States, May 3, 2023–April 14, 2024. CDC. News release. May 30, 2024. Accessed June 12, 2024. https://www.cdc.gov/mmwr/volumes/73/wr/mm7321a3.htm.

2. CDC. Respiratory Syncytial Virus Infection (RSV). July 17, 2023. Accessed May 20, 2024. https://www.cdc.gov/rsv/research/index.html.

3. Study: Outcomes of RSV Associated with Acute Respiratory Failure. Pharmacy Times. News release. May 22, 2024. Accessed June 12, 2024. https://www.pharmacytimes.com/view/study-outcomes-of-rsv-associated-with-acute-respiratory-failure.