This case was reported in a literature article and described the occurrence of chikungunya virus infection in a 3-month-old female patient who received Hepatitis B vaccine. On an unknown date, the patient received Hepatitis B vaccine at an unknown dose. On an unknown date, 91 days after receiving Hepatitis B vaccine, the patient experienced chikungunya virus infection (serious criteria hospitalization and life threatening), septic shock (serious criteria hospitalization, GSK medically significant and life threatening), macular rash (serious criteria hospitalization), fever (serious criteria hospitalization), decreased activity (serious criteria hospitalization), tachycardia (serious criteria hospitalization), tachypnea (serious criteria hospitalization), swelling (serious criteria hospitalization), maculopapular rash (serious criteria hospitalization), atelectasis (serious criteria hospitalization) and poor feeding infant (serious criteria hospitalization). The patient was treated with vancomycin, ceftriaxone and Normal Saline. On an unknown date, the outcome of the chikungunya virus infection, septic shock, macular rash, fever, decreased activity, tachycardia, tachypnea, swelling, maculopapular rash, atelectasis and poor feeding infant were recovered/resolved. The reporter considered the chikungunya virus infection, septic shock, macular rash, fever, decreased activity, tachycardia, tachypnea, swelling, maculopapular rash, atelectasis and poor feeding infant to be related to Hepatitis B vaccine. Additional information was provided. This case was reported in a literature article and described the occurrence of septic shock and chikungunya virus infection in a 3-month-old female child who was vaccinated with unspecified hepatitis B virus vaccine (manufacturer unknown). The patient was a healthy term infant born to a healthy 28-year-old G1P1  (1 pregnancy, 1 term birth) woman via spontaneous vaginal delivery. Her birth weight was 2.9 kg. The patient's mother and father were both healthy. The mother had not experienced symptoms of chikungunya virus before. No information on patient's concomitant medication or concurrent condition was provided. On an unspecified date the patient received the hepatitis B vaccine (administration route and site unspecified; dosages unknown; batch number not provided) after birth. When the patient was 1 month old, she travelled with her mother, where she spent 40 days in a suburban area before returning home. During the trip, the patient was breastfed exclusively, and her health was unremarkable; she experienced no illnesses or exposure to the  jungle or animals. However, 20 days before returning home. The patient's mother had developed high fevers, joint pain malaise, headaches, and vomiting, and was diagnosed with chikungunya virus solely on the basis of her clinical findings and symptoms, which began to resolve after 7 days. No medications were given to the patient before her presentation to the emergency department. On an unspecified date, an unknown period after vaccinations and within 6 days of returning home, the patient developed a macular rash that started on her extremities and spread to her face within 24 hours; she also was experiencing fevers up to 38.8 deg.C. The patient had only 1 wet diaper in the preceding 15 hours. 12 hours before admission, her mother noticed that the patient had started to breastfeed poorly and have decreased activity. In early winter of 2014, the patient was admitted to hospital with septic shock. When the patient arrived in the emergency department, she was febrile, tachycardic, and tachypneic, and had a maximum temperature of 40.5 deg.C, a pulse of 188 beats per minute, and a respiratory rate of 52 breaths per minute. Arterial blood gas testing revealed a pH of 7.1, partial pressure of carbon dioxide (pCO2) of 55 mmHg, and a lactate concentration of 0.5 mmol/L. She was given supplemental oxygen via nasal cannula and intravenous fluids before transfer to the pediatric intensive care unit. The patient's weight, length, and head circumference were all appropriate for her age. Her vital signs 10 hours after triage and after being intubated and placed on mechanical ventilation included a blood pressure of 61/32 mmHg after 4 boluses 20 ml/kg each of normal saline, a pulse of 172 beats per minute, a temperature of 39.2 Degrees C, and a respiratory rate of 12 breaths per minute. Significant findings on her physical examination included generalized swelling, tachycardia, and poor air entry laterally. A diffuse maculopapular rash was noted throughout her trunk, face, and extremities. The patient's white blood cell count was 7.1 x 103 uL with no bands and 77% segmented neutrophils. Her platelet count was 324 x 103 uL. Her liver enzyme levels were normal. Results of a malaria slide review were negative. Blood and urine cultures were performed. The patient was initially too unstable for us to perform a lumbar puncture. A chest radiograph revealed a small area of atelectasis on the left side but no focal pneumonia. Broad-spectrum antibiotic coverage was started with vancomycin and ceftriaxone. After initial fluid resuscitation and the initiation of vasoactive infusions, the vasoactives were gradually weaned over 4 days, and the patient was extubated on the sixth day of admission. The patient's rash gradually resolved over 10 days. A cerebrospinal fluid examination could not be performed initially because of he infant's instability. Results of a lumbar puncture performed on the third day of admission after 48 hours of antibiotics were unremarkable, with 0 white blood cells per uL, 10 red blood cells per uL, a glucose level of 73 mg/dL, and a protein level of 35 mg/dL. Gram staining revealed rare erythrocytes and no organisms. Test results of a nasopharyngeal swab to detect common viruses such as respiratory syncytial virus, human metapneumovirus, influenza, parainfluenza, rhinovirus, enterovirus, and adenovirus were also negative. Blood, urine, and cerebrospinal fluid cultures resulted in no growth. Dengue titers were negative. Results of the brain magnetic resonance imaging with and without contrast were normal. Chikungunya infection was high in the differential on the basis of the mother's recent infection and exposures. Results of a test of the infant's mixed-serum immunoglobulin G (IgG) and IgM titers for chikungunya virus were positive, but it was unclear if this positivity was a result of the patient's infection or a previous infection of the mother. Results of a commercial qualitative real-time polymerase chain reaction (PCR) assay for chikungunya virus RNA from the serum also were positive, which confirmed the diagnosis. Her diagnosis was septic shock secondary to chikungunya virus infection. Ceftriaxone and vancomycin were continued for a total of 10 days to treat the patient for culture-negative sepsis. Chikungunya virus results arrived on the eighth day of hospitalization. By the ninth day of admission, the patient was back to her normal health; she was breastfeeding regularly again and engaging in an appropriate level of activity for her age. The patient was discharged after completing 10 days of antibiotics. Because Chikungunya virus infection is a nationally notifiable disease, this case was reported to the local health department. This case had been considered serious due to hospitalisation/ life-threatening. The authors did not comment on the relationship between septic shock and Chikungunya virus infection and unspecified hepatitis B virus vaccine. The author stated, "Septic shock caused by Chikungunya virus, as occurred in our patient, is a rare occurrence. Severe life-threatening complications have been observed during the acute phase. Although bacterial co-infection with Chikungunya virus has seemed unlikely to date, the literature has documented severe bacterial co-infections with viral infections such as influenza and dengue. These data supported our decision to administer a course of antibiotics for culture-negative sepsis in our patient."