BREAKING: RSV Shots Linked to Over 200 Safety Signals — Serious Neurological, Cardiac, and Pregnancy Harms Identified

New VAERS study finds major signals for fetal death, preterm birth, paralysis, Guillain-Barré syndrome, heart failure, thrombocytopenia, and mini-strokes.

By Nicolas Hulscher, MPH

A new peer-reviewed pharmacovigilance study just published in Human Vaccines & Immunotherapeutics analyzed nearly 18,000 adverse event reports tied to the three FDA-approved RSV vaccines — Pfizer’s Abrysvo, GSK’s Arexvy, and Moderna’s mRESVIA.

The findings are alarming: Pfizer’s vaccine generated 103 positive safety signals, including fetal death, hemorrhage in pregnancy, and preterm birth, while GSK’s vaccine generated 91 signals, including paralysis, Guillain-Barré syndrome, and mini-strokes. Both carried strong signals for immune destruction (thrombocytopenia) and serious neurological damage — in some cases appearing over 200× more likely compared to other vaccines.

Researchers used standard pharmacovigilance methods (Reporting Odds Ratios and Bayesian algorithms) to compare how often certain events were reported after RSV vaccination versus all other vaccines in the system.

And while both Pfizer’s and GSK’s vaccines generated thousands of reports, Moderna’s mRNA RSV shot had too few reports (just 35 cases) to allow for meaningful analysis. That doesn’t mean it’s safe — only that there isn’t enough post-market data yet to detect patterns.

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Key Safety Signals — Compared to Other Vaccines

GSK Arexvy (RSVPreF3)

• Ascending flaccid paralysis: ~120× more likely — ROR 119.56; IC 6.03

• Areflexia (loss of reflexes): ~20× more likely — ROR 20.03; IC 4.14

• CSF protein increased (neuro injury marker): ~11× more likely — ROR 11.42; IC 3.41

• Transient ischemic attack (mini-stroke): ~2.9× more likely — ROR 2.89; IC 1.51

• Guillain-Barré syndrome (GBS): ~6.9× more likely — ROR 6.85; IC 2.70

• Immune thrombocytopenia: ~4.1× more likely — ROR 4.14; IC 2.01

• Congestive cardiac failure: ~2.8× more likely — ROR 2.79; IC 1.46

Pfizer Abrysvo (RSVpreF)

• Premature delivery: ~267× more likely — ROR 266.61; IC 6.20

• Preterm premature rupture of membranes: ~203× more likely — ROR 203.27; IC 6.09

• Premature rupture of membranes: ~152× more likely — ROR 152.39; IC 5.94

• Hemorrhage in pregnancy: ~118× more likely — ROR 118.43; IC 5.78

• Fetal death: ~33.8× more likely — ROR 33.82; IC 4.68

• Induced labor: ~101× more likely — ROR 101.43; IC 5.68

• Cesarean section: ~121× more likely — ROR 120.87; IC 5.79

• Guillain-Barré syndrome (GBS): ~8.5× more likely — ROR 8.49; IC 2.96

• Facial paralysis: ~3.4× more likely — ROR 3.41; IC 1.73

• Immune thrombocytopenia: ~3.6× more likely — ROR 3.55; IC 1.79

• Platelet count decreased: ~5.0× more likely — ROR 4.98; IC 2.25

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These aren’t just nuisance side effects. They include paralysis, strokes, cardiac failure, immune destruction, and pregnancy complications. For Pfizer’s vaccine — marketed directly to pregnant women — signals included hemorrhage in pregnancy, preterm birth, fetal hypokinesia, and fetal death.

These serious safety signals corroborate what randomized trial data have already shown. A major meta-analysis by Marchand et al found that RSVpreF vaccination during pregnancy was linked to a 24% increased risk of preterm delivery, alongside higher rates of systemic maternal adverse events.

Taken together, both the clinical trial evidence and real-world surveillance converge on the same conclusion: these vaccines carry disproportionate risks to mothers and infants that cannot be ignored.

Regulators should pause RSV vaccination in seniors and pregnant women until these alarming safety signals are independently investigated.

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Nicolas Hulscher, MPH

Epidemiologist and Foundation Administrator, McCullough Foundation

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