Sex: U
Vaccine: VARCEL
Symptoms: Polymerase chain reaction positive, Rash, Varicella post vaccine, Varicella virus test positive
Clinical narrative: This literature marketed report as received from the authors of the published article, titled as stated below, refers to a 7 year old patient of unknown gender. The patient's concurrent conditions, medical history and concomitant medications were not reported.  On 03-DEC-2015, Public Health (PH) was notified by a local indergartengrade 2 school that a student aged 8 years (the index patient) had been sent home because of a rash suspected to be varicella (chickenpox); the rash had not been observed the previous day. The index patient rode a school bus and was the first student on and the last off each day. Public health investigators subsequently linked three more cases in children to sharing the same school bus as the index patient and they also received diagnoses of varicella. The first case was diagnosed in a student aged 7 years, who received an unspecified amount of doses (reported as fully immunized) of varicella virus vaccine live (oka/merck) (manufacturer unknown) injection (exact dose and route of administration were not reported) on unknown dates. On 15-DEC-2015, the patient had rash onset. Diagnosis of varicella was subsequently (date unspecified) confirmed from a cutaneous lesion swab by polymerase chain reaction (PCR). This student rode on the same bus as the index patient for approximately 40 minutes in each direction each day. The patient was not related to or interacted socially with members of household of the index patient. It was not known whether the student sat next to or otherwise interacted with the index patient during the bus ride.  The reported coverage with at least 1 dose of varicella vaccine in the school was 96% and for coverage with 2 doses was 95%. The overall coverage rate with all required immunizations for the school was 95%; 2% of children had waivers, and immunizations for 3% of children were incomplete. This outbreak of varicella appeared to have begun with an adult case of herpes zoster and resulted in nine cases of varicella in children residing in three households. The timeline of rash onsets was consistent with the 1021 day incubation period for varicella. With continued 2-dose childhood varicella vaccination and declining incidence of varicella among children, transmission of varicella initiated by adults with herpes zoster could become increasingly more likely. This investigation also strongly suggested that transmission of varicella to children occurred while riding the same school bus as the index patient. Varicella transmission on school buses was plausible and was implicated previously as a risk factor for transmission in a large varicella outbreak reported in China. This investigation underscored the importance of maintaining high 2-dose varicella immunization levels to reduce risk for disease transmission. The high immunization rates achieved in this school likely limited the scope of the varicella outbreak. The outcome of the events was not reported. The reporters considered the events to be related to varicella virus vaccine live (oka/merck) (manufacturer unknown). Additional information has been requested.