Novel H1N1 Influenza Exposure in a Neonatal Unit – Infection Control Measures and Oseltamivir Prophylaxis in Neonates

Background: Novel H1N1 influenza (nH1N1) has been declared a pandemic by WHO.  There have been 156 pediatric deaths since April 2009.  Neonatal health-care associated influenza has been reported, but in seasonal influenza years appears mild, due to transplacental maternal antibody protection.  During influenza pandemics there is limited immunity among childbearing aged women and thus limited neonatal immunity.  Prevention measures and antiviral prophylaxis in neonates have not been well studied and little data exist regarding dosing and activation of oseltamivir (OST) in neonates.

Objective:

To describe the course of, response to and outcomes of an nH1N1 exposure in a neonatal unit (NU).

Methods:

In June 2009 a respiratory therapist (RT) cared for a patient with pneumonia, then developed cough and fever 3 days later.  The symptoms abated by day 3 of illness and the RT returned to work in the NU.  By the end of the RT’s shift the symptoms recurred. The following day the index patient’s PCR test was positive for nH1N1.  Infection Prevention (IP) personnel excused the RT from work and tested for nH1N1.  IP, in consultation with NC Dept of Health and CDC, provided all exposed infants prophylactic OST 1.5 mg/kg BID for 10 days.  Two patients did not receive the medication due to parental refusal. The FDA had previously issued an emergency use authorization approving OST for treatment in this age group.

            Infants were monitored for signs of infection and if symptomatic, placed in droplet isolation and tested for nH1N1.  IP protocols were put in place immediately including restriction of ill staff and visitors from unit, cohorting of  non-exposed infants, restriction of interchange of staff between ED and NU, and strict hand washing.

Results:

Four neonates developed respiratory symptoms but all were nH1N1 PCR negative.  Thirty infants received OST and 20 serum samples from routine clinician specimens were used to measure OST blood levels.  Neonates were able to convert OST to its active metabolite and the pharmacokinetics supported the empiric dosing used (data from Dr David Kimberlin at UAB Birmingham).

            Ascertainment of adverse drug effects (ADEs) in neonates is difficult.  Possible ADEs were noted including hypoglycemia in 3 neonates and respiratory decompensation in 4 (3 required mechanical ventilation).  All the neonates survived and were discharged from the hospital. 

Conclusions:

Prevention of nH1N1 in NUs is paramount given the lack of data regarding safety and efficacy of antivirals in this population.  IP measures are vital.  Neonates can activate OST to its active metabolite.  If OST is prescribed, dosing for neonates should be 1.5 mg/kg bid and neonates should be closely monitored for ADEs.  This experience prompted our health system to adopt a mandatory employee vaccination program with 97% uptake of seasonal influenza vaccine to date.  Further knowledge is needed regarding nH1N1 prevention and treatment in neonates.