Serum sickness-like reaction (SSLR); Swelling of her joints; A generalized urticarial rash; High fever; Worsening Arthralgia; Initial information was received on 27-Oct-2020 regarding an unsolicited valid serious case from other healthcare professional issued in a literature article.   Literature abstract- Case Description: A 4-year-old female developed a generalized urticarial rash with swelling of her joints six days after receiving MMR, varicella, DTaP, and IPV vaccines. She was started on prednisolone by her pediatrician for presumed SSLR however was subsequently admitted with high fevers and worsening arthralgia. Her CRP, procalcitonin and ESR were all elevated and her respiratory viral panel was positive for adenovirus. Her complement levels(C3, C4) were normal. IV methylprednisolone was started with dramatic improvement and resolution in symptomatology over the course of 48 hours.She was diagnosed with SSLR due to routine vaccinations and was discharged on a prednisone taper with instructions to space out vaccinations in the future to elicit the causal vaccine.  Discussion: SSLR's are usually attributed to medications and self-resolve after discontinuation of the offending agent. SSLR due to MMR, varicella, DTaP, and IPV vaccinations have not yet been described in literature. Refractory or severe symptoms with high fever, debilitating arthralgia, and persistent urticaria can be treated with prednisone.    This case involves a four years old female patient who experienced serum sickness-like reaction (SSLR) (Serum sickness-like reaction), generalized urticarial rash (urticaria), swelling of joints (joint swelling), high fever (pyrexia) and arthralgia (arthralgia), while she received vaccines POLIOMYELITIS VACCINE (INACTIVATED), DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE, VARICELLA ZOSTER VACCINE [VARICELLA VACCINE] and MEASLES VACCINE, MUMPS VACCINE, RUBELLA VACCINE [MMR].  Medical history, past medical treatments, past vaccinations, concomitant medication and family history were not provided.  On an unknown date, the patient received a dose of suspect POLIOMYELITIS VACCINE (INACTIVATED) (Produced by unknown manufacturer, lot number and expiration date were not reported) a dose of DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE (Produced by unknown manufacturer, lot number and expiration date were not reported), a dose of VARICELLA VACCINE (Not produced by Sanofi Pasteur, lot number and expiration date were not reported) and a dose of MMR (Not produced by Sanofi Pasteur, lot number and expiration date were not reported) via unknown route at an unknown administration site for prophylactic vaccination.  On an unknown date, the patient developed a serious generalized urticarial rash (urticaria) and swelling of joints (joint swelling), six days following the administration of POLIOMYELITIS VACCINE (INACTIVATED), DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE, VARICELLA VACCINE and MMR.  On an unknown date, the patient developed a high fever (pyrexia) and arthralgia (unknown latency) following the administration of POLIOMYELITIS VACCINE (INACTIVATED), DIPHTHERIA, TETANUS AND ACELLULAR PERTUSSIS VACCINE, VARICELLA VACCINE and MMR. On an unknown date, patient was diagnosed with serious serum sickness-like reaction (SSLR)(unknown latency) following vaccination. The patient was hospitalized for these events on an unknown date.  Relevant laboratory test results included: The results of C-reactive protein (CRP), Procalcitonin and Red blood cell Sedimentation Rate (ESR) (Erythrocyte Sedimentation Rate) were elevated. Respiratory viral panel was positive for adenovirus. Complement factor C3 and C4 were normal.  Final diagnosis was serum sickness-like reaction (SSLR).  The patient was treated with PREDNISOLONE (PREDNISOLONE) for Serum sickness-like reaction. METHYLPREDNISOLONE (METHYLPREDNISOLONE) and PREDNISONE (PREDNISONE) was also given to patient during hospitalization.  The patient was recovered from all the events as there was dramatic improvement and resolution in symptomatology over the course of 48 hours. The patient was discharged from the hospital on Prednisone taper with instructions to space out vaccination in future to elicit the casual vaccine. Outcome of serum sickness-like reaction (SSLR) was not reported.  There will be no information on the batch number for this case.; Sender's Comments: This case concerns a four years old female patient who experienced serum sickness-like reaction (SSLR), urticaria, joint swelling, pyrexia and arthralgia, after vaccination with POLIOMYELITIS VACCINE (INACTIVATED) (unknown manufacturer), DIPHTHERIA, TETANUS AND NOS PERTUSSIS VACCINE (unknown manufacturer), VARICELLA VACCINE (other manufacturer) and MMR(other manufacturer). The time to onset is compatible for events urticaria and joint swelling and unknown for rest of the events. Laboratory data involved C-reactive protein (CRP), Procalcitonin and Red blood cell Sedimentation Rate (ESR) (Erythrocyte Sedimentation Rate) all were elevated. Respiratory viral panel was positive for adenovirus and complement factor C3 and C4 were normal. The patient's medical history, medical condition at time of vaccination, concomitant medication were not reported. Based upon the reported information, the role of an individual vaccine cannot be assessed.