Nikhil Prasad Fact checked by:Thailand Medical News Team Jun 20, 2026 2 hours, 6 minutes ago
Medical News: A newly published study from Germany is raising fresh questions about a little-known neurological symptom reported by some individuals after COVID-19 vaccination: persistent fasciculations, or involuntary muscle twitches. While the researchers emphasize that the vast majority of cases appeared to be benign, the findings highlight a phenomenon that remains poorly understood and continues to puzzle neurologists.
German researchers investigate ten cases of persistent fasciculations reported after COVID-19 vaccination
The study was conducted by researchers from the Department of Neurology with Experimental Neurology at Charité–Universitätsmedizin Berlin, the German Center for Neurodegenerative Diseases (DZNE) Berlin, the Center for Stroke Research Berlin, and the Berlin Institute of Health (BIH), all based in Germany. The research team examined ten patients who developed persistent fasciculations shortly after receiving COVID-19 vaccines.
What Are Fasciculations?
Fasciculations are small, spontaneous muscle twitches that occur beneath the skin and are often visible as brief rippling or flickering movements. These contractions usually do not move a limb or joint but can occur repeatedly and persist for long periods.
Although fasciculations are widely recognized as a symptom that can occur in amyotrophic lateral sclerosis (ALS), they are also frequently seen in healthy individuals and in people with a condition known as Benign Fasciculation Syndrome (BFS). Stress, fatigue, anxiety, strenuous exercise, excessive caffeine intake, and certain metabolic disturbances have all been associated with the development of fasciculations.
For many patients, however, the appearance of persistent muscle twitching can be frightening because of its association with serious neurological diseases.
Ten Cases Investigated
The researchers evaluated ten patients ranging in age from 28 to 69 years old. The group consisted of five men and five women with an average age of 42.4 years.
Symptoms began anywhere from six hours to thirteen days after vaccination, with the average onset occurring about five days later. The fasciculations persisted between two and twelve months by the time the patients were assessed.
Most patients initially noticed twitching in a localized area before it gradually spread to multiple muscle groups throughout the body. In one case, the symptoms started in the same arm where the vaccine had been administered.
In addition to fasciculations, many participants reported a variety of neurological complaints. These included tingling sensations, fatigue, neuropathic pain, limb pain, muscle aches, headaches, dizziness, visual disturbances, facial numbness, and subjective cognitive difficulties.
What Did the Tests Show?
The patients underwent extensive neurological evaluations including blood testing, nerve conduction studies, and electromyography (EMG).
Laboratory investigations were largely normal. Two patients tested positive for certain myositis-related antibodi
es, but neither showed clinical signs of muscle inflammation or muscle disease.
Electrophysiological testing was unremarkable in six patients. Four patients demonstrated fasciculation activity on EMG studies, confirming the presence of abnormal muscle twitching. Importantly, nine of the ten patients showed no evidence of progressive neurological disease and were diagnosed with probable Benign Fasciculation Syndrome.
This
Medical News report notes that one patient stood apart from the others. That individual developed muscle weakness, muscle wasting, and widespread abnormalities on neurological testing that fulfilled accepted diagnostic criteria for ALS. However, the researchers stressed that no conclusions can be drawn regarding a causal relationship between vaccination and ALS based on a single case.
Why Are Neurologists Puzzled?
According to the investigators, the biggest unanswered question is whether the fasciculations were actually triggered by vaccination or whether the timing was coincidental.
The researchers pointed out that fasciculations following COVID-19 vaccination have only rarely been described in medical literature. Because reporting systems depend heavily on voluntary submissions and many individuals may never seek medical care for muscle twitching, the true frequency of the condition remains unknown.
The study also highlighted another possibility known as the nocebo effect, in which concerns and expectations surrounding side effects can influence how symptoms are perceived and reported. At present, there is insufficient evidence to determine which explanation is correct.
Conclusions
The findings suggest that persistent fasciculations reported after COVID-19 vaccination are usually benign and most closely resemble Benign Fasciculation Syndrome rather than serious neurodegenerative disease. Nevertheless, the appearance of long-lasting muscle twitching after vaccination remains an intriguing clinical observation that warrants further investigation. The researchers emphasize that larger prospective studies are needed to determine whether these cases represent a true vaccine-related phenomenon, an unrelated coincidence, or a combination of biological and psychological factors. They also stress that the benefits of COVID-19 vaccination continue to greatly outweigh the risk of rare neurological adverse events.
The study findings were published in the peer reviewed journal: Vaccines.
https://www.mdpi.com/2076-393X/14/6/541
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