Conference Coverage

‘Substantial burden’ of enterovirus meningitis in young infants



– A prospective international surveillance study has provided new insights into the surprisingly substantial clinical burden of viral meningitis caused by enteroviruses and human parechoviruses in young infants, Seilesh Kadambari, MBBS, PhD, said in his ESPID Young Investigator Award Lecture at the annual meeting of the European Society for Paediatric Infectious Diseases.

This comprehensive study captured all cases of laboratory-confirmed enterovirus (EV) and human parechovirus (HPeV) meningitis in infants less than 90 days old seen by pediatricians in the United Kingdom and Ireland during a 13-month period starting in July 2014, a time free of outbreaks. Dr. Kadambari, a pediatrician at the University of Oxford (England), was first author of the study. It was for this project, as well as his earlier studies shedding light on congenital viral infections, that he received the Young Investigator honor.

Among the key findings of the U.K./Ireland surveillance study: The incidence of EV/HPeV meningitis was more than twice that of bacterial meningitis in the same age group and more than fivefold higher than that of group B streptococcal meningitis, the No. 1 cause of bacterial meningitis in early infancy. Moreover, more than one-half of infants with EV/HPeV meningitis had low levels of inflammatory markers and no cerebrospinal fluid pleocytosis, which underscores the importance of routinely testing the cerebrospinal fluid for viral causes of meningitis in such patients using modern molecular tools such as multiplex polymerase chain reaction, according to Dr. Kadambari.

“Also, not a single one of the patients with EV/HPeV meningitis had a secondary bacterial infection – and that has important implications for management of our antibiotic stewardship programs,” he observed.

The study (Arch Dis Child. 2019 Jun;104(6):552-7) identified 668 cases of EV meningitis and 35 of HPeV meningitis, for an incidence of 0.79 and 0.04 per 1,000 live births, respectively. The most common clinical presentations were those generally seen in meningitis: fever, irritability, and reduced feeding. Circulatory shock was present in 43% of the infants with HPeV and 27% of the infants with EV infections.

Of infants with EV meningitis, 11% required admission to an intensive care unit, as did 23% of those with HPeV meningitis. Two babies with EV meningitis died and four others had continued neurologic complications at 12 months of follow-up. In contrast, all infants with HPeV survived without long-term sequelae.

Reassuringly, none of the 189 infants who underwent formal hearing testing had sensorineural hearing loss.

The surveillance study data have played an influential role in evidence-based guidelines for EV diagnosis and characterization published by the European Society of Clinical Virology (J Clin Virol. 2018 Apr;101:11-7).

An earlier study led by Dr. Kadambari documented a hefty sevenfold increase in the rate of laboratory-confirmed viral meningo-encephalitis in England and Wales during 2004-2013 across all age groups (J Infect. 2014 Oct;69[4]:326-32).

He attributed this increase to improved diagnosis of viral forms of meningitis through greater use of polymerase chain reaction. The study, based upon National Health Service hospital records, showed that more than 90% of all cases of viral meningo-encephalitis in infants less than 90 days old were caused by EV, a finding that prompted the subsequent prospective U.K./Ireland surveillance study.

Dr. Kadambari closed by noting the past decade had seen a greatly improved ability to diagnose congenital viral infections, but those improvements are not good enough.

“In the decade ahead, we hope to improve the management of this poorly understood group of infections,” the pediatrician promised.

Planned efforts include a cost-effectiveness analysis of a cytomegalovirus vaccine, an ESPID-funded research project aimed at identifying which EV/HPeV strains are most responsible for outbreaks and isolated severe disease, and gaining insight into the host-immunity factors associated with a proclivity to develop EV/HPeV meningitis in early infancy.

Dr. Kadambari reported having no financial conflicts regarding his studies, which was funded largely by Public Health England and university grants.

SOURCE: Kadambari S et al. Arch Dis Child. 2019;104:552-7.

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