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Review of Research Found Immunizations Safe; Most Adverse Events Not Likely to Repeat


Patients who have adverse reactions to vaccines are unlikely to have a repetition of the same problem upon reimmunization. Vaccinating a second and third time is safe for most patients, according to the study, "Risk of Recurrence of Adverse Events Following Immunization: ASystematic Review," published in the September 2017 Pediatrics (published online Aug. 28). Researchers reviewed 29 studies presenting the outcome of reimmunization of patients who experienced an adverse effect after immunization. They found the risk of recurrence of serious effects, such as anaphylaxis and seizures was approximately 1 percent, although research on these patients was limited. Repeat of more moderate reactions like decreased appetite, vomiting, fever, sleepiness and allergic-like reactions ranged widely from 4 to 48 percent, and recurrences were generally less severe or similar to the initial episode. The study authors concluded that the research shows that reimmunizations are safe in most patients. Because patients who have severe reactions often decline future immunizations, there is limited information about them, and high-quality studies estimating the vaccine-specific risk of recurrence and predictors of recurrence are needed to inform doctors and patients.


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