CDC Preliminary Analysis: RSV vaccines for seniors linked to Guillain-Barré Syndrome

The following is from The Vaccine Reaction.

On Feb. 29, 2024, the U.S. Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) presented a preliminary analysis that showed that 23 adults over the age of 65 who received a respiratory syncytial virus (RSV) vaccine developed Guillain-Barré syndrome (GBS).  

When a person develops GBS, including after an infection or vaccination, the body attacks the peripheral nerves. GBS symptoms begin with muscle weakness and numbness or tingling in different parts of the body and recovery can be complete or paralysis of one or more limbs can occur, including full body paralysis, which can lead to death.

The CDC’s analysis evaluated preliminary rates of GBS following one dose of either GSK plc’s RSVPreF3+AS01 (AREXVY) vaccine or Pfizer, Inc.’s RSVPreF (ABRYSVO) vaccine and compared it to the rates of GBS in an historical control group.

The data used in the study was collected from the Centers for Medicare & Medicaid Services (CMS) administrative claims and enrollment information that was derived from CMS Medicare Shared Systems Data (SSD). The population studied included CMS Medicare Beneficiaries over age 65 years and older enrolled in Medicare Fee-for-Service.

The study period for the ABRYSVO RSV vaccine was from May 31, 2023 to Dec. 2, 2023 and for AREXVY from May 3, 2023 to Dec. 2, 2023.

The people who were used as part of the analysis either had one dose of ABRYSVO or AREXVY after the CDC’s RSV vaccine authorization and prior to the data through Dec. 2, 2023.

Increased Risk of GBS Observed for Both RSV Vaccines

The analysis showed an elevated risk of GBS, with 13 cases of GBS following one dose of ABRYSVO and less than 11 cases of GBS following a dose of AREXVY.

According to the data, in the 21-day period following vaccination, the rate of GBS among seniors who received ABRYSVO was 4.6 per 1 million vaccine doses and 1.1 per 1 million vaccine doses for those who received AREXVY.

Data from the U.S. Food and Drug Administration (FDA) also illustrated a higher- than-expected number of GBS cases being reported in RSV vaccine recipients.

Tom Shimabukuro, MD, director of the Immunization Safety Office at the CDC said:

Taken together, these data suggest a potential increased risk [of GBS after RSV vaccinations].

Health officials at the CDC were aware that cases of GBS had been identified in clinical trials prior to the approval for public use, and that there were surveillance systems in place monitoring any new cases.

Pfizer and GSK Representatives Pledge to Investigate the Reported GBS-RSV Link

Representatives of Pfizer and GSK attended the ACIP meeting and made a statement noting that a safety signal for a vaccine is a complicated process to resolve. Reema Mehta, Head of Risk Assessment and Management at Pfizer said:

Pfizer is committed to the continuous monitoring and evaluation of the safety of Abrysvo and is conducting four safety studies to look into the possibility of vaccine-related GBS.

Mehta added that Pfizer will conduct four different safety studies to investigate the incidence of GBS following RSV vaccination.

GSK representatives said that the current data on GBS is limited and uncertain. A spokesperson from the company said that the vaccine maker intends to initiate a controlled epidemiological study to evaluate the GBS link to the RSV vaccine and is the process of currently developing the study. They stated:

Patient safety is our highest priority, and we will continue to monitor diligently all safety data reported in the ongoing RSV older adult clinical trials and in post-marketing pharmacovigilance systems.

Link to article here.

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2 thoughts on “CDC Preliminary Analysis: RSV vaccines for seniors linked to Guillain-Barré Syndrome”

  1. I listened to Slanted and can’t wait to listen to or read the rest of your books. I think you profiled a historian that wrote a book on Fed Reserve. Who would that have been? I can’t find where I wrote it down. Thanks for all you are doing.

  2. Dear Ms. Attkisson,

    Thanks for your reportiing on this issue. The GBS risks are concerning, but there is much greater concern to address that can be identified in reviewing the clinical trial design and subsequent result reporting which is very deceptive…. a classic tactic from the vaccine industry that should be easily identified by the FDA reviewers. Additionally, the “study” that the vaccine manufacturers promise to perform will be designed to find safety. Epidemiologic-based studies can be designed/manipulated to prove whatever result is desired.

    To demonstrate what occurred in the Abrysvo clinical trial, the following is my analysis of the Pfizer RSV vaccine, Abrysvo, that I sent to my Florida OB/GYN colleagues about 6 to 8 weeks ago on ACOG’s District 12 social media site, “ACOG Engage.” I receiived only one reply from a colleague who had some insightful comments, but failed to acknowledge the fact that the clinical trial of this vaccine was invalidated due to the fact that no placebo was used in the control group. Our reliance on public health authorities to “tell us” how to care for our patients has led to an accelerating loss of critical thinking in our physician population which jeopardizes our patient’s health.

    Dear colleagues,
    I was hoping to participate in the “RSV vaccination (Abrysvo) of pregnant women” webinar on Wednesday to present some of my concerns about using this vaccine in pregnancy, but, unfortunately, I had a few deliveries that prevented my participation.
    Like many of you, I am concerned about the rush to expose pregnant women to foreign, toxic substances without adequate safety evaluations. An analysis of the Abrysvo Clinical Trial information available in their product information sheet located at
    reveals concerning information about the outcomes in this clinical trial. Additionally, it is important to note that this is only the information that the manufacturer allows us clinicians to evaluate. They own the raw data from the clinical trial and will never reveal that to us unless it is subpoenaed in lawsuits. Regardless, the information that they made available to us should cause us all to pause in our motivation to protect newborns from RSV infections by administering this new medication to women during the most precious time of their lives – pregnancy. Additionally, it is concerning that ACOG and the FDA did not identify or investigate these concerning facts, particularly the fact that the control group did not receive a placebo, prior to endorsing this vaccine for all pregnant women.
    A review of the Abrysvo clinical trial information reveals the following problems:
    1. The control group did not receive a placebo, so there is no way to determine side effects.
    2. The absolute risk reduction for RSV-related hospitalization under 6 mos. of age from the vaccine is 0.72%. Relative risk reduction should not be used to determine efficacy and global recommendations as was promoted from the study.
    3. There will be 1.4 more preterm births for each vaccine-prevented RSV-related hospitalization under 6 mos. of age.
    4. Approximately 64,210 pregnant women must be vaccinated to prevent 1 RSV-related death under 6 mos. of age.
    5. There will be approximately 642 more preterm births in RSV-vaccinated pregnant women for each RSV-related death prevented under 6 mos. of age.
    6. “High risk” pregnant women were excluded from the study.
    Explanations and calculations are provided below:
    Problem 1 – The control group did not receive a placebo. It is impossible to assess the side effects of the vaccine because, like in most other vaccine trials, the control group did NOT receive a placebo. In this trial, the control group received the exact same vaccine solution as the treatment group, but without the RSV antigens. This “placebo” solution included 2 forms of tromethamine – tromethamine and tromethamine hydrochloride – a tissue damaging agent in the extravascular space. It also included sucrose, mannitol and polysorbate. There is no credible explanation for this placebo choice. Why did they not administer saline as the placebo? This is the only way to assess the true side effects of the vaccine. So, we begin with a dishonest clinical study that eliminated the ability to assess side effects.
    Problem 2 – They chose to promote Relative Risk Reduction rather than Absolute Risk Reduction. The absolute risk reduction (ARR) for the study endpoint of hospitalization for RSV for children 6 mos. of age or younger is 0.72%. This does not sound quite as appealing as the 57% – 85% relative risk reductions that the manufacturer touts in its marketing materials, does it? This means that 139 pregnant women must be vaccinated to prevent 1 RSV-related hospitalization in infants under 6 mos. of age. Applying this ARR of 0.72% to US birth data and RSV death data creates a concerning picture as highlighted, below.
    Problem 3 – More preterm births if pregnant women are vaccinated for RSV. The study group had a 1% higher preterm birth rate than the control group (5.7% vs 4.7% = a negative 1% ARR). This equates to 1.4 preterm deliveries for every RSV-related hospitalization prevented. (139 pregnant women vaccinated x 1% more preterm deliveries for each prevented hospitalization = 1.4 more preterm deliveries.)
    Next, let’s consider childhood death rates from RSV to highlight additional issues to be considered for this vaccine. According to ACOG’s September 2023 Practice Advisory, “Maternal Respiratory Syncytial Virus Vaccination”
    (located at, there are between 100 – 300 children who die from RSV infections annually in the United States under the age of 5. Let’s assume, liberally, that 100 of those deaths are in children under 6 mos. of age. Also, for the subsequent calculations we will use the number of US annual births of 3,660,000 annually. This is 2021 data.
    Problem 4 – We must vaccinate 64,210 women to prevent 1 RSV-related death under 6 mos. of age. Death should be the main preventable endpoint in this study. Here are the calculations that result in this conclusion:
    Calculate death rate of hospitalized children: In the study 44/3480 control patients were hospitalized = 1.264% of children under 6 mos of age.
    Apply 1.264% to the number of annual births = 1.264% x 3,660,000 annual births = 46,262 hospitalized children under 6 mos. of age. 100 of those hospitalized children will die = 100/46,262 = 0.216% death rate of hospitalized children without vaccination.
    Calculate number of RSV deaths if all pregnant women are vaccinated: . If pregnant women are vaccinated, 19/3495 = 0.5436% children under 6 mos. of age are hospitalized as per the clinical trial results. 0.5436% x 3,660,000 = 19,896 hospitalized children under 6 mos. of age if all pregnant women in the US are vaccinated. Assume the same death rate (0.216%) if vaccine-exposed children are hospitalized = 19,896 hospitalized children x 0.216% = 43 children die. If no vaccines are administered to pregnant women, then 100 children under 6 mos. of age die annually as per historical data. Vaccinating pregnant women will result in 100 – 43 = 57 fewer deaths than if no vaccinations are given.
    How many women must be vaccinated in pregnancy annually to prevent 1 RSV-related death under age 6 mos. of age?: If vaccinating all 3,660,000 pregnant women annually prevents 57 RSV-related deaths under age 6 mos, then 3,660,000/57 = 64,210 pregnant women must be vaccinated to prevent 1 RSV-related death under age 6 mos.
    Problem 5 – 642 pregnant women will experience preterm deliveries to prevent each RSV-related death under age 6 mos.
    1% excess preterm deliveries if vaccinated x 3,660,000 births = 36,600 more preterm births if all pregnant women are vaccinated. If all pregnant women are vaccinated, 57 fewer RSV-related deaths under 6 mos. of age will occur annually = 36,600/57 = 642 more preterm births to prevent each RSV-related death under 6 mos. of age.
    Problem 6 – Thousands of more women will experience side effects to prevent each RSV-related death under 6 mos. of age. However, we are unable to calculate the side effect rate because the control group did not receive a placebo, as reviewed in problem 1, above.
    Problem 7 – “High Risk” pregnant women were excluded from the study. Given these exclusionary criteria, how can ACOG or the FDA extrapolate their recommendations to the excluded groups?
    In conclusion, analyzing the manufacturer’s-provided clinical trial data reveals disturbing results that should be re-evaluated by our watchdog organization, the FDA. It is extremely disappointing to see that both the FDA and ACOG are recommending a new medication to pregnant women with such concerning data regarding the adverse effects associated with its proposed efficacy. Additionally, it is irresponsible of these organizations to recommend any drug or vaccine that has not undergone a true clinical trial which requires the use of a placebo for the control group. Despite the contamination of the control group with a non-placebo, this vaccine still does not present the profile of a drug that should be used in pregnancy. Therefore, its use should be abandoned until a real clinical trial utilizing a true placebo (saline injection) for the control group is performed to allow for a better analysis of outcomes and benefits utilizing proper statistical analyses, as presented here.
    Finally, this analysis reveals the importance of us clinicians utilizing our independent critical thinking and intellectual curiosity to protect our patients from harm. The health authorities have recently provided us all with many reasons to question their consensus opinions. We must use our own clinical experience and judgement and not implement recommendations from these organizations without confirming the legitimacy and integrity of their consensus guidance or analyses. Taking the path of least resistance resulting from misplaced, and unearned, trust in these organizations can result in adverse outcomes by blindly following their recommendations. If this is representative of what we will find by doing a little bit of digging into pharmaceutical manufacturer clinical studies, then “vaccine hesitancy” is certainly a warranted protective response that should be encouraged by us all. First, do no harm!


    Dan McDyer, MD

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