Patient description: A 3-day-old Asian female infant presents with jaundice that started a day ago. She was born at 38w3d of gestation, after an uncomplicated pregnancy. The family history is unremarkable. The baby is breastfed. Vital signs are reported as: axillary temperature: 36.3°C, heart rate: 154 beats/min, respiratory rate: 37 breaths/min, and blood pressure: 65/33 mm Hg. Her weight is 3.2 kg, length is 53 cm, and head circumference 36 cm. Her sclera are yellow and her body is icteric. No murmurs or any other abnormalities are detected in the heart and lung auscultation. Her liver and spleen are normal on palpation. Laboratory results are as follows: Serum total bilirubin: 21.02 mg/dL Direct bilirubin of 2.04 mg/dL AST: 37 U/L ALT: 20 U/L GGT: 745 U/L Alkaline phosphatase: 531 U/L Creatinine: 0.3 mg/dL Urea: 29 mg/dL Na: 147 mEq/L K: 4.5 mEq/L CRP: 3 mg/L Complete blood cell count within the normal range. She is diagnosed with uncomplicated neonatal jaundice that may require phototherapy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-40.0,  Respiratory Syncytial Virus Infections Pregnant women must meet all of the following to be eligible to participate: 1. ≥18 and ≤40 years-of-age. 2. Singleton pregnancy of 33 to 35 weeks gestation on the day of planned vaccination. 3. Good general maternal health as demonstrated by Medical history (including history of adverse reactions to prior vaccines and allergies) Physical examination including at least vital signs (blood pressure, pulse, respirations, and oral temperature); weight; height; examination of the HEENT, cardiovascular, pulmonary, gastrointestinal (abdominal), musculoskeletal, lymphatic, and dermatologic organ systems; and documentation of fetal heart tones Clinical laboratory parameters including normal blood urea nitrogen, creatinine, ALT, AST, total bilirubin, alkaline phosphatase (ALP), hemoglobin, white blood count, and platelet count; and serologic of infection with hepatitis B (HBV) and C (HCV) viruses and HIV (as required). Note that normal ranges for vital signs and clinical laboratory parameters will be based on third trimester values published in Sheffield et al. [2013] and/or reference ranges for the third trimester of pregnancy of the central laboratory. 4. Documentation that fulfills one of the following Detailed (level II) second trimester or later anatomic ultrasound with no significant anatomic or growth abnormalities identified; OR Routine second trimester or later ultrasound with no significant anatomic or growth abnormalities identified, PLUS at least one of the following Normal first trimester screening (based on ultrasound + serum analytes); or Normal cell-free fetal DNA; or Normal chorionic villus sampling (CVS) or amniocentesis; or Normal second trimester maternal serum quadruple screen; or  Pregnant women will be excluded if there is historical, physical examination, or laboratory evidence of any of the following 1. Symptomatic cardiac or pulmonary disease requiring chronic drug therapy, including hypertension and asthma. Asthma will be exclusionary if the subject is receiving chronic systemic glucocorticoids at any dose or inhaled glucocorticoids at any dose >500µg per day of beclamethasone or fluticasone, or >800μg per day of budesonide. 2. Pre-pregnancy body mass index (BMI) of ≥35 or <18.5. 3. Hemoglobinopathy (including known sickle trait or thalassemias, even if asymptomatic) or blood dyscrasias. 4. Hepatic or renal dysfunction. 5. Established diagnosis of seizure disorder, regardless of therapy. 6. Auto-immune disease or known immunodeficiency syndrome. 7. Endocrine disorders, including (but not limited to) hyperthyroidism, untreated hypothyroidism, and glucose intolerance (e.g., diabetes mellitus type 1 or 2) antedating pregnancy, or occurring during pregnancy and requiring interventions other than diet for control. 8. History of major gynecologic or major abdominal surgery, including bariatric surgery. 9. Known HIV, HBV, or HCV infection, as assessed by serologic tests conducted during the current pregnancy or as a procedure during the screening period of the study. 10. Primary genital herpes simplex (HSV) infection during the current pregnancy. 11. Current alcohol or drug abuse. 12. Documentation that current pregnancy results from fertility treatments, rape, or incest. 13. Documentation that the infant will be a ward of the state or be released for adoption. 14. Neuro-psychiatric illness deemed likely to interfere with protocol compliance, safety reporting, or receipt of pre-natal care; or requiring treatment with psychotropic drugs. 15. History/presence of deep venous thrombosis or thromboembolism, or the use of anticoagulants during pregnancy. 16. Untreated red blood cell allo-immunization. 17. Prior stillbirth or neonatal death, or multiple (≥3) spontaneous abortions. 18. Prior preterm delivery ≤34 weeks gestation or having ongoing intervention (medical/surgical) in current pregnancy to prevent preterm birth. 19. Greater than five (5) prior deliveries. 20. Previous infant with a known genetic disorder or major congenital anomaly. 21. Receipt of investigational drugs or immune globulins (with the exception of prophylactic anti-Rho D immune globulin) within six (6) months prior to the administration of the study vaccine. 22. Chronic administration (defined as more than 14 continuous days) of immunosuppressants or other immune-modifying drugs within 6 months prior to the administration of the study vaccine. An immunosuppressant dose of glucocorticoid will be defined as a systemic dose ≥10mg of prednisone per day or equivalent. The use of topical, inhaled, and nasal glucocorticoids will be permitted except for the limit established in criterion #1. 23. Any other physical, psychiatric or social condition which may, in the investigator's opinion, increase the risks of study participation to the maternal subject or the fetus/infant; or may lead to the collection of incomplete or inaccurate safety data