#18,093
In 1976, when I was still a fledgling paramedic, the U.S. government rolled out an emergency flu vaccine in anticipation of a swine flu (H1N1) pandemic that never materialized (you can read my first hand account HERE).
Although only about 1 in 100,000 vaccine recipients were thought to be affected - and many of the media accounts were overblown - the reputation of vaccines was badly (and, in many ways, unfairly) damaged.Instead, that early flu shot was linked to a modest increase in Guillain-Barré syndrome (GBS) - a rare, often transitory, but occasionally fatal form of paralysis.
Had the anticipated H1N1 pandemic materialized, the negative impact from the vaccine would likely have been tolerated - or at least lost in the avalanche of severe flu cases - but instead the virus was a no-show, and several hundred people were injured by that early flu vaccine.
Even without taking vaccines, there is always a background rate of GBS - usually 1 to 2 cases per 100,000 each year - often linked to viral or bacterial infections. The CDC describes the disorder:
What is Guillain-Barré syndrome (GBS)?
Guillain-Barré syndrome (GBS) is a rare disorder in which a person’s own immune system damages their nerve cells, causing muscle weakness and sometimes paralysis. GBS can cause symptoms that usually last for a few weeks. Most people recover fully from GBS, but some people have long-term nerve damage. In very rare cases, people have died of GBS, usually from difficulty breathing. In the United States, an estimated 3,000 to 6,000 people develop GBS each year.
What causes GBS?
The exact cause of GBS is unknown, but about two-thirds of people who develop GBS experience symptoms several days or weeks after they have been sick with diarrhea or a respiratory illness. Infection with the bacterium Campylobacter jejuni is one of the most common risk factors for GBS. People also can develop GBS after having the flu or other infections (such as cytomegalovirus and Epstein Barr virus). On very rare occasions, they may develop GBS in the days or weeks after getting a vaccination.Vaccine technology has come a long way in 50 years, and while GBS is sometimes linked to getting vaccinated, the benefits of getting the vaccine generally far outweigh the risks. Some past blogs include:
Association Between Guillain-Barré Syndrome and COVID-19 Infection and Vaccination: A Population-Based Nested Case-Control Study
Nature Study: Greater Risk Of Neurological Complications From COVID Infection Than From Vaccine
BMJ: No Substantial Link Between Flu Vaccines And Guillain-Barre Syndrome
Lancet: The Influenza - Guillain Barré Syndrome Connection
Last summer the U.S. approved a new RSV vaccine for those 60 years of age or older, which was heavily promoted last fall. RSV in the elderly can be severe, and even fatal, and according to the CDC:
Each year, it is estimated that between 60,000-160,000 older adults in the United States are hospitalized and 6,000-10,000 die due to RSV infection
Given the heavy impact of RSV infection on the elderly, pending more information, the advice from the CDC remains:
RSV vaccination continues to be recommended for adults aged ≥60 years using shared clinical decision-making (9). CDC and FDA are conducting active safety evaluations to assess risks for GBS and other adverse events of special interest after RSV vaccination.
I've posted some excerpts from a much longer report. Follow the link to read it in its entirety.
Early Safety Findings Among Persons Aged ≥60 Years Who Received a Respiratory Syncytial Virus Vaccine — United States, May 3, 2023–April 14, 2024
Weekly / May 30, 2024 / 73(21);489–494
Anne M. Hause, PhD1; Pedro L. Moro, MD1; James Baggs, PhD1; Bicheng Zhang, MS1; Paige Marquez, MSPH1; Michael Melgar, MD2; Amadea Britton, MD2; Erin Stroud, MD1; Tanya R. Myers, PhD1; Jeffrey Rakickas, MD1; Phillip G. Blanc, MD3; Kerry Welsh, MD3; Karen R. Broder, MD1; John R. Su, MD1; David K. Shay, MD1 (VIEW AUTHOR AFFILIATIONS)View suggested citation
Summary
What is already known about this topic?
The Food and Drug Administration licensed Arexvy and Abrysvo vaccines in May 2023 for prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in adults aged ≥60 years. In trials, Guillain-Barré syndrome (GBS) was identified as a potential safety concern.
What is added by this report?
Findings are consistent with those from trials; reports of GBS (5.0 and 1.5 reports per million doses of Abrysvo and Arexvy vaccine administered, respectively) were more common than expected background rates.
What are the implications for public health practice?
The Advisory Committee on Immunization Practices (ACIP) recommends adults aged ≥60 years may receive 1 dose of RSV vaccine. Population-based surveillance will evaluate the potential risk for GBS to guide ACIP recommendations.
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Abstract
In May 2023, the Food and Drug Administration (FDA) licensed Arexvy and Abrysvo vaccines for prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in adults aged ≥60 years. In prelicensure trials, Guillain-Barré syndrome (GBS) was identified as a potential safety concern. During August 4, 2023–March 30, 2024, at least 10.6 million adults aged ≥60 years received a recommended RSV vaccine. During May 3, 2023–April 14, 2024, CDC reviewed data reported after RSV vaccination to V-safe, an active U.S. surveillance system that invites enrolled participants to complete web-based surveys, and reports to the Vaccine Adverse Event Reporting System (VAERS), a passive, voluntary surveillance system that accepts adverse event reports from the public, providers, and manufacturers. Findings from V-safe and VAERS were generally consistent with those from trials. Reporting rates of GBS after RSV vaccination in VAERS (5.0 and 1.5 reports per million doses of Abrysvo and Arexvy vaccine administered, respectively) were higher than estimated expected background rates in a vaccinated population. CDC and FDA are conducting population-based surveillance to assess risks for GBS and other adverse events. Findings from these studies will help guide development of Advisory Committee on Immunization Practices recommendations.
Introduction
Respiratory syncytial virus (RSV) infection can cause lower respiratory tract disease, hospitalization, and death in older adults and is responsible for substantial morbidity and mortality among this age group (1). The Food and Drug Administration (FDA) licensed Arexvy (GlaxoSmithKline Biologicals [GSK]) and Abrysvo (Pfizer Inc.) vaccines on May 3 and May 31, 2023, respectively, for prevention of lower respiratory tract disease caused by RSV in adults aged ≥60 years (2,3). On June 21, 2023, the Advisory Committee on Immunization Practices (ACIP) recommended that adults aged ≥60 years may receive a single dose of RSV vaccine, using shared clinical decision-making (4). Guillain-Barré syndrome (GBS) was identified as a potential vaccine safety concern in clinical trials of both RSV vaccines (4). To characterize early post-marketing vaccine safety findings in adults aged ≥60 years after RSV vaccination, CDC reviewed health surveys and adverse events reported to V-safe, an active U.S. surveillance system that sends web surveys to enrolled participants during the 6 weeks after vaccination, and the Vaccine Adverse Event Reporting System (VAERS), a passive, voluntary surveillance system that monitors adverse events after vaccination, during May 3, 2023–April 14, 2024* (5). During August 4, 2023–March 30, 2024, approximately 7.2 million adults aged ≥60 years received GSK RSV vaccine, and 3.4 million received Pfizer RSV vaccine.† Among the 16,220 V-safe participants aged ≥60 years who reported receiving an RSV vaccine and completed one or more daily surveys, 39.0% reported at least one symptom after vaccination; 0.4% of participants reported receiving medical care. VAERS received 3,200 reports of adverse events after RSV vaccination among persons aged ≥60 years (including 28 verified reports of GBS); 91.2% of reports were classified as nonserious. Estimated VAERS GBS reporting rates after RSV vaccination were 5.0 and 1.5 reports per million administered doses of Pfizer and GSK vaccines, respectively. CDC and the partnership between FDA and the Centers for Medicare & Medicaid Services are conducting population-based surveillance assessments of RSV vaccine safety.
(SNIP)
Discussion
This review provides early findings from V-safe and VAERS surveillance systems during the first months of GSK and Pfizer RSV vaccine administration among U.S. adults aged ≥60 years. The findings in this report are generally consistent with those from safety data collected in prelicensure clinical trials, including the observance of GBS cases¶¶¶ (2,3).
In V-safe, injection site and systemic reactions were more frequently reported among those who received GSK than among those who received Pfizer vaccine; few participants reported receiving medical care (2,3). Expected vaccination reactions (e.g., pain in extremity, headache, and fatigue) were among the most frequently reported events among nonserious VAERS reports. Using VAERS data, estimated GBS reporting rates after RSV vaccination among persons aged ≥60 years were 5.0 and 1.5 reports per million doses of Pfizer and GSK vaccine administered, respectively.
VAERS reporting rates of GBS after mRNA COVID-19 vaccination were used to estimate expected background rates of GBS in this study population; no excess risk for GBS was observed after mRNA COVID-19 vaccinations in active Vaccine Safety Datalink surveillance (7). VAERS reporting rates for GBS among adults aged ≥65 years were 0.43 and 0.54 per million doses of Pfizer-BioNTech and Moderna COVID-19 vaccines, respectively**** (8). Thus, using the reporting rate for mRNA COVID-19 vaccines as an estimate of background rate, reports of GBS after RSV vaccination were more common than expected. Two deaths among vaccine recipients who had been diagnosed with GBS were reported.
Limitations
The findings in this report are subject to at least four limitations. First, V-safe is a voluntary program, and data might not be representative of the vaccinated population. Second, VAERS is a passive surveillance system and is subject to reporting biases, underreporting (especially of nonserious events), and incomplete data reporting. Third, VAERS generally cannot determine causal associations between adverse events and vaccination (5). Finally, because these data do not include a comparison group of unvaccinated persons with a similar likelihood of receiving an RSV vaccine, estimating the magnitude of risk for serious but rare outcomes (e.g., GBS) after vaccination is not possible.
Implications for Public Health Practice
On February 29, 2024, ACIP announced that, based on a thorough review of currently available data, the estimated benefits of RSV vaccination continued to outweigh potential risks. RSV vaccination continues to be recommended for adults aged ≥60 years using shared clinical decision-making (9). CDC and FDA are conducting active safety evaluations to assess risks for GBS and other adverse events of special interest after RSV vaccination. Results of these studies will help guide future CDC RSV vaccine recommendations.
Acknowledgments
Charles Licata, Isaac McCullum, Seth Meador, Amna Mehmood, Narayan Nair, Carmen Ng, Suchita Patel, Tom Shimabukuro, Jonathan Tewodros, Peter Van Ameyden Van Duym, Jared Woo.
