The baby girl was born at 34 and 3/7 weeks gestational age to a 21‐year‐old P0101 via C‐section secondary to chorioamnionitis and fetal tachycardia. Prior to delivery, the mother had flulike symptoms, highly suspected to be a result of H1N1 influenza. Therefore, the mother was started on Tamiflu. She received 2 doses prior to delivery. Apgar scores at 1 and 5 minutes were 9 and 9. Birth weight was 2.675 kg (appropriate for gestational age). The baby was immediately brought to the NICU for a rule‐out sepsis workup and isolation because of the mother's symptoms of flu and chorioamnionitis and because the baby was tachypneic with mild subcostal retractions. There was nodirect contact between baby and mother. On arrival at the NICU, she had a respiratory rate of 71/min and O2 saturation of 97%. Chest x‐ray showed mild RDS. Meanwhile, rapid influenza antigen test for the mother was done and it was negative, however H1N1 PCR was also sent which laler turned out positive. The CDC was called for recommendations on the management of the patient. Rapid influenza and H1N1 PCR were sent on the baby, and both were negative. The CDC didn't recommend prophylaxis for the baby; therefore, the baby wasn't started on Tamiflu. She was tolerating PO feeds well. She was treated with antibiotics until her blood and CSF cultures were negative, at which time the antibiotics were stopped. She was afebrile throughout the stay and was discharged stable on day of life 7.
The 2009 H1N1 influenza virus was first detecled in people in Ihe United States in April 2009. Transmission is by droplet, the same as the regular flu. There have been no reports of vertical transmission. The patient in this case may have not had enough exposure to the mother to infect the baby with H1N1 flu. According to the Emergency Use Authorization by CDC, Tamiflu should not be routinely used for prophylaxis in infants less than 3 months of age because of extremely limited pharmacokinetic data to guide dosing in this age group. Prophylaxis with Tamiflu in infants less than 3 months of age should be reserved for cases in which the exposure is significant and the risk of severe illness is considered high, such as in babies with underlying cardiac or pulmonary disease. The FDA does authorize oseltamivir use for treatment of infants less than 1 year under the Emergency Use Authorization. However, they do not recommend use for infants less than 37 weeks' gestation because there is little safety information for use on those infants.
H1N1 exposure in newborns should be avoided if possible. There have been no reports of vertical transmission, so avoidance can be achieved by droplet precautions. Routine antiviral prophyalaxis is not done for newborns. The CDC is a helpful resource in difficult cases.
D. Rauch, Baxter, consultant.