Febrile Infant With Rhinovirus: Can You Really Stop Looking for a Bacterial Infection?

William T. Basco, Jr., MD, MS


June 30, 2016

Infant Viral Illness and Bacterial Infection Risk

Among febrile infants up to 90 days of age, the identification of a viral pathogen by either direct antigen testing or polymerase chain reaction (PCR) lowers the likelihood that the infant has an invasive bacterial infection (urinary tract infection [UTI], bacteremia, or meningitis). Rhinovirus, one of the more common pediatric viruses, specifically has been excluded from previous evaluations of how viral illnesses might modify bacterial infection risk in febrile infants.

Therefore, a recent study[1] aimed to evaluate the risk for concomitant bacterial infection in febrile infants positive for human rhinovirus by PCR. This was a retrospective evaluation of data from 22 hospitals in the Intermountain Healthcare system (based in Salt Lake City, Utah). Study infants were 1-90 days of age with febrile illness, had respiratory viral testing using PCR, and had been admitted to the hospital during 2007-2106. Among those tested, 55% were positive for at least one respiratory virus. Rhinovirus was the most common virus detected (38%) and was the only virus detected in 35% of the infants. Respiratory syncytial virus was the second most common virus (7%).

A bacterial infection was found in 9.5% of all of the infants (6.6% UTIs, 2.6% bloodstream infections, and 0.3% meningitis). Among infants who were positive for a virus other than rhinovirus, 3.5% had a bacterial infection compared with 7.5% of the rhinovirus-infected infants and 13% of infants who were viral PCR negative.

In general, the data revealed that the presence of rhinovirus in infants aged up to 28 days was associated with a lower risk for bloodstream infection or meningitis, although non-rhinovirus positivity was even more "protective." The rate of UTI among infants with rhinovirus was not different from for infants who were virus-negative. There were 12 total cases of meningitis, and 10 of those were in viral PCR-negative infants. No cases of meningitis occurred among virus-positive infants aged 1-28 days, compared with seven cases of meningitis among virus-negative infants.

However, the presence of rhinovirus among infants aged 1-28 days was not associated with lower risk for bloodstream infection. The investigators concluded that human rhinovirus is commonly identified in febrile infants. For infants aged 29-90 days, however, rhinovirus-positive patients may be less likely to have invasive bacterial illnesses except for UTIs.


It's been interesting to watch what we've learned about how we can limit bacterial infection evaluation among febrile young infants. In general, viral positivity reduces the need for meningitis evaluation of children older than 28 days, and bloodstream infections are very rare as well in that group. UTIs remain prevalent in all febrile infants under 90 days of age.

However, this study and others have demonstrated that infants younger than 28 days of age remains a population of concern, even when they are virus positive, and should receive a complete evaluation for UTI and invasive bacterial infection.


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