Injection side effects are common after receiving a vaccine or other treatments delivered through a shot.
This can happen withsubcutaneousinjectionsdelivered under the skin andintramuscular injectionsdelivered into a large muscle.
High Fever
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Afeverhigher than 100.4 F following an injection warrants immediate medical care.
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Fevers this high may be due to an infection triggered by needle contamination.Fever with chillsis especially concerning.
Other signs of post-injection infection include:
Sterile injection practices reduce the risk of infection.
This includes using a single-use syringe and needle from a new sealed package.
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Injection Site Pain
Most subcutaneous and intramuscular injections cause relatively little pain.
This is especially true if you have a fever, muscle aches, and fatigue.
However, in some cases, the swelling may be significant and persistent.
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Suspected abscesses should be seen without delay.
Leukotrienes can also causebronchoconstriction, or the narrowing of the airways that deprives the body of oxygen.
However, in some cases, the reaction may be delayed and only cause symptoms after several hours.
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When treated, the fatality rate of anaphylaxis is 0.65%.
Left untreated, anaphylaxis can sometimes lead to death within 15 minutes.
Summary
Injection side effects are usually mild and resolve within a day or two.
However, certain side effects may indicate something far more serious, like an infection or anaphylaxis.
Saint Luke’s Hospital.Understanding post-injection inflammation.
Centers for Disease Control and Prevention.Preventing unsafe infection practices.
Peng B, Wei M, Zhu FC, Li JX.The vaccines-associated Arthus reaction.HumVaccin Immunother.
2021;49:35-39. doi:10.1016/j.ajem.2021.05.006
American Academy of Allergy, Asthma, and Immunology.Anaphylaxis.
Reber LL, Hernandez JD, Galli SJ.The pathophysiology of anaphylaxis.J Allergy Clin Immunol.
