child's mother was vaccinated with VARIVAX after the delivery; chickenpox/ rash concerning for chickenpox/ Varicella Zoster Virus; meningitis/ varicella zoster virus/ VZV meningitis with cutaneous lesions; child's mother was vaccinated with VARIVAX after the delivery; the infant was breastfeeding at the time; This spontaneous report was received from a physician and refers to an 1-month-old (reported also as 3-week-old), female patient. The patient did not receive any concomitant medications, no known drug allergies (NKDA). She never had chickenpox, shingles or prior history of herpes zoster nor herpes zoster ophthalmicus reported.  On 20-DEC-2020, the patient's mother was vaccinated with varicella virus vaccine live (oka/merck)(VARIVAX) 0.5 ml, in right arm, lot # T020652, upon internal validation was determined to be a valid lot #, expiration date was not reported but established as 16-JUN-2022 (strength and route of administration were not reported) since it was determined during a prenatal screen, that she was not immune to varicella (for prophylaxis). The physician was not sure, if the patient (baby) was in close contact or in the room at the time the mother was vaccinated. On approximately 09-JAN-2021 (reported as on 09-JAN-2021 to 11-JAN-2021), the patient's mother developed a rash. The patient (baby) was breastfeeding at the time the mother had developed a rash, and was switched to formula on an unknown date in January 2021 (reported also as shortly thereafter) (exposure via breast milk, exposure to vaccinated person).  On approximately 12-JAN-2021, reported as between 12-JAN-2021 and 13-JAN-2021, the patient developed rash. On an unspecified date in January 2021, a newborn presented to the hospital with a rash concerning for chickenpox (chickenpox) (sought medical attention). The patient presented a fever on admission and underwent clinical testing. Meningitis panel using cerebrospinal fluid (CSF) was analyzed and was positive for varicella zoster virus (VZV) (meningitis viral), also reported as VZV meningitis with cutaneous lesions. The physician wanted to send viral isolates. The time interval since exposure to vaccine was reported as immediate. The physician reported possible secondary transmission, rash vesicles of over 100 lesions; generalized rash- chickenpox, and meningitis with positive VZV polymerase chain reaction (PCR) test in CSF (secondary transmission). Magnetic resonance imaging (MRI) showed leptomeningeal enhancement and confirmed varicella meningitis. On approximately 14-JAN-2021, the patient started antiviral treatment with intravenous (IV) acyclovir (reported also as an oral antivirals). On the same date, before the treatment, the specimen sample was collected from the patient's CSF. On an unspecified date in January 2021, CSF red blood cells (RBC)  result was of 4200 (unit not provided), CSF glucose of 58 (unit not provided) and CSF white blood cells (WBC) of 17 (unit not provided). It was reported, that the treatment included also unspecified "antibacterials".  On 18-JAN-2021, at the day # 4 of the acyclovir treatment, the specimen was collected from the patient's forehead and bilateral lower extremities vesicle/lesion.  On 19-JAN-2021, the call was made to physician to confirm receiving requested program information. On that date, the patient was currently on day # 5 of acyclovir treatment and was clinically feeling okay, did not have fever. The physician was not sure, if they would send samples to the Centers for Disease Control and Prevention (CDC) or another lab or if would participate in the Program, since the physician would need to discuss further with the manager. The physician provided additional case information regarding the newborn. The program information was e-mailed to the physician as requested. The physician had additional questions upon receipt of the program information and an additional phone call was made. Upon speaking with the physician during the second call, the reporter stated, that they would like to send samples through the Program. Detailed shipping instructions were provided and reviewed including instructions about how to store a CSF sample frozen and additional case information was received. Additionally, the physician reported, that one lesion sample from the patient was obtained from 3 skin lesions and placed on transport media on day 4 of acyclovir treatment. After reading the program information, the physician wanted to know if this sample would be adequate to test since it was placed on transport media. The physician would try to obtain a fresh rash sample without transport media on the morning of 20-JAN-2021 to submit for testing.   The physician also stated, that the patient had some blisters remaining, but most had dried up "at this point". The physician would like to submit a 1 ml frozen sample for strain identification (CSF was obtained prior to the start of acyclovir and unspecified "antibacterials").  On 20-JAN-2021, at the day # 6 of acyclovir treatment, a call was made to the physician to help arrange for the shipping of samples. On that day, the specimen sample was collected from the patient's right foot vesicle/lesion. The physician confirmed, that there would be four total samples sent: 1 ml of CSF from infant stored frozen (collected prior to the start of "antivirals"), 1 lesion swab from the patient collected on day 4 of acyclovir treatment and placed on transport media, 1 lesion swab from the patient collected on day 5 of acyclovir treatment stored in a dry container, and 1 lesion scab from the mother's abdomen. The patient reportedly did not have any known health issues, was doing awesome and very well at the time of a call, but had performed an immunological work-up for further evaluation. The call concluded with discussion that all four samples would be picked up by the courier by the end of business.  On 25-JAN-2021 it was confirmed by the physician, that the 3 patient's specimens were sent to the laboratory on 20-JAN-2021. The samples were delivered. The results were still not obtained. The outcome of the events was recovering/resolving. Additional information has been requested. The causality between the suspect vaccine and the events was not provided.  The patient was enrolled in the Program to identify if VZV is present and if it is present, to identify if it is associated with the wild-type (WT) VZV strain or with the Oka/Merck vaccine strain.  Upon internal review, the event meningitis viral was determined to be medically significant.  This is one of the two linked reports of mother and child (the mother's case # 2101USA011308).; Sender's Comments:  US-009507513-2101USA011308: