Pfizer BioNTech Covid Vaccine and Hyperreflexia - a phase IV clinical study of CDC and FDA data


Hyperreflexia is found among people who get Pfizer BioNTech Covid Vaccine, especially for people who are female, 60+ old, and in the first week of getting the vaccine.

The phase IV clinical study analyzes which people get Pfizer BioNTech Covid Vaccine and have Hyperreflexia. It is created by eHealthMe based on reports of 401,887 people who have side effects when getting Pfizer BioNTech Covid Vaccine from the CDC and the FDA, and is updated regularly. You can use the study as a second opinion to make health care decisions.

Phase IV trials are used to detect adverse drug outcomes and monitor drug effectiveness in the real world. With medical big data and AI algorithms, eHealthMe is running millions of phase IV trials and makes the results available to the public. Our original studies have been referenced on 600+ medical publications including The Lancet, Mayo Clinic Proceedings, and Nature.

On May, 28, 2023

401,887 people reported to have side effects after getting Pfizer BioNTech Covid Vaccine.
Among them, 19 people (0.0%) have Hyperreflexia.

What is Hyperreflexia?

Hyperreflexia (overactive or over responsive reflexes) is found to be associated with 1,034 drugs and 633 conditions by eHealthMe.

Number of reports submitted per year:

Pfizer biontech covid vaccine and Hyperreflexia?

Time to have Hyperreflexia from when people get Pfizer BioNTech Covid Vaccine *:

  • on the same day: 23.53 %
  • in the first week: 47.06 %
  • in the first 30 days: 29.41 %
  • after 30 days: 0.0 %

Gender of people *:

  • female: 57.89 %
  • male: 42.11 %

Age of people *:

  • 0-1: 0.0 %
  • 2-9: 5.56 %
  • 10-19: 0.0 %
  • 20-29: 16.67 %
  • 30-39: 11.11 %
  • 40-49: 22.22 %
  • 50-59: 11.11 %
  • 60+: 33.33 %

Did people recover *:

  • yes: 13.33 %
  • no: 86.67 %

Death as an outcome *:

  • yes: 5.26 %
  • no: 94.74 %

# of vaccine dose *:

  • 1: 42.86 %
  • 2: 57.14 %
  • 3+: 0.0 %

Common side effects people have besides Hyperreflexia *:

  1. Weakness: 9 people, 47.37%
  2. Myelitis Transverse (a neurological condition consisting of an inflammatory process of the spinal cord): 6 people, 31.58%
  3. Paraesthesia (sensation of tingling, tickling, prickling, pricking, or burning of a person's skin with no apparent long-term physical effect): 5 people, 26.32%
  4. Clonus (series of involuntary, rhythmic, muscular contractions and relaxations): 4 people, 21.05%
  5. Hypoaesthesia (reduced sense of touch or sensation): 4 people, 21.05%
  6. Headache (pain in head): 4 people, 21.05%
  7. Gait Disturbance: 4 people, 21.05%
  8. Neurological Examination Abnormal: 4 people, 21.05%
  9. Urinary Retention (the inability to completely or partially empty the bladder): 4 people, 21.05%
  10. Diarrhea: 3 people, 15.79%

* Approximation only. Some reports may have incomplete information.

Related studies

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Vaccine side effects by duration, gender, age and dose:

Common Pfizer biontech covid vaccine side effects:

Browse all side effects of Pfizer BioNTech Covid Vaccine:

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How the study uses the data?

The study is based on data from the CDC and the FDA.

Who is eHealthMe?

With medical big data and proven AI algorithms, eHealthMe provides a platform for everyone to run phase IV clinical trials. We study millions of patients and 5,000 more each day. Results of our real-world drug study have been referenced on 600+ medical publications, including The Lancet, Mayo Clinic Proceedings, and Nature. Our analysis results are available to researchers, health care professionals, patients (testimonials), and software developers (open API).


WARNING: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on is for informational purposes only, and is not a substitute for medical advice, diagnosis, or treatment provided by a qualified healthcare provider. All information is observation-only. Our phase IV clinical studies alone cannot establish cause-effect relationship. Different individuals may respond to medication in different ways. Every effort has been made to ensure that all information is accurate, up-to-date, and complete, but no guarantee is made to that effect. The use of the eHealthMe site and its content is at your own risk.

If you use this eHealthMe study on publication, please acknowledge it with a citation: study title, URL, accessed date.

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