Health Officials Investigate Potential Link Between RSV Vaccines and Nervous System Disorder in Elderly

Health officials in the United States are investigating a potential connection between two new RSV vaccines and cases of a rare nervous system disorder in older adults. The inquiry is based on fewer than two dozen cases reported among more than 9.5 million vaccine recipients. While the available information is currently insufficient to establish a causal relationship between the vaccines and the illnesses, the numbers of cases are higher than expected, prompting officials to gather more data to determine if the vaccines are causing the problem. The investigation was presented at a meeting of an expert panel that provides vaccine policy advice to the Centers for Disease Control and Prevention.

Guillain-Barre Syndrome Under Investigation

Officials are specifically looking into more than 20 cases of Guillain-Barre syndrome (GBS), a rare illness wherein a person’s immune system damages nerve cells, leading to muscle weakness and paralysis. The CDC estimates that 3,000 to 6,000 people develop GBS in the U.S. each year, with a higher prevalence among older individuals. Although most people make a full recovery from the syndrome, some may experience permanent nerve damage. While Guillain-Barre can occur after viral infections, there have also been instances where it has been linked to vaccinations.

RSV Vaccines and Prevalence of Guillain-Barre Syndrome

RSV, or respiratory syncytial virus, is known to cause cold-like symptoms and can pose significant risks to infants and the elderly. Last year, the CDC recommended a single dose of RSV vaccine for individuals aged 60 and older, with two options available from Pfizer and GSK. It was emphasized that patients should consult their doctors about the vaccines before making a decision. Before the shots were approved for sale, instances of Guillain-Barre had been identified in clinical trials, and surveillance systems were put in place to monitor for potential problems.

Analysis of Reported Cases

An analysis of the reports collected from these surveillance systems revealed that about two-thirds of the Guillain-Barre cases occurred in individuals who received the Pfizer vaccine, known as Abrysvo. Follow-up tracking is also being conducted for recipients of Arexvy, the vaccine manufactured by GSK. Health officials estimate that about two cases of Guillain-Barre may be seen in every 1 million people who receive a vaccine. The analysis found that the rate of Guillain-Barre cases was lower for the GSK vaccine, but recipients of the Pfizer shot reported 4.6 cases per million.

Potential Increased Risk

Data from the U.S. Food and Drug Administration also indicated a higher-than-expected number of Guillain-Barre cases among RSV vaccine recipients, particularly among those who received the Pfizer shot. Dr. Tom Shimabukuro, a CDC vaccine safety monitoring official, highlighted that the data suggests a potential increased risk in RSV vaccine recipients aged 60 and older, which requires further exploration.

Manufacturer Statements and Overall Benefits of Vaccination

During the meeting, officials from GSK and Pfizer provided brief statements, expressing the complexity of determining a safety signal. Pfizer reiterated their commitment to continuously monitor and evaluate the safety of Abrysvo, conducting four safety studies to investigate the possibility of vaccine-related GBS. CDC officials also presented estimates demonstrating that the vaccines have prevented thousands of hospitalizations and hundreds of deaths from RSV. Current data indicates that the benefits of vaccination outweigh the potential risks associated with it.

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