By Stan Deresinski, MD, FACP, FIDSA

Clinical Professor of Medicine, Stanford University

Dr. Deresinski reports no financial relationships relevant to this field of study.

SYNOPSIS: An evaluation of 18 infants with COVID-19 in the first three months of their lives found that the illness generally was not severe despite the presence of very high viral loads.

SOURCE: Mithal LB, Machut KZ, Muller WJ, Kociolek LK. SARS-CoV-2 infection in infants less than 90 days old. Pediatrics 2020; doi: 10.1016/ j.jpeds.2020.06.047

Mithal and colleagues retrospectively identified infants younger than 90 days of age with positive SARS-CoV-2 real-time polymerase chain reaction (RT-PCR) tests at the Ann & Robert Lurie Children’s Hospital in Chicago from April 11 to May 12, 2020. During that time, testing was performed on all children in whom COVID-19 was considered because of symptoms, as well as all asymptomatic patients as part of routine screening at the time of hospital admission or before procedures. Testing was performed at a variety of sites, including a drive-through center, the emergency department and other ambulatory settings, intensive care units, and the general inpatient setting.

Of the 171 infants tested, 18 (10%) were positive; none had a significant past medical history. Fifteen of the 18 were tested in the emergency department and three were tested in outpatient settings. Fever was present in 14 (77.8%), while two had cough as their sole symptom. One had choking with feeding, and one, who was screened because the parents were infected, was asymptomatic. Fourteen (78%) had close contacts and/or family members with symptoms consistent with COVID-19.

Half of the infants were admitted to the general inpatient service and none subsequently required intensive care. The reasons for admission included clinical observation, evaluation of feeding tolerance, and empiric intravenous antibiotics. Eight of the nine admitted had fever, while four had cough or tachypnea, four had poor feeding, three had vomiting, and one developed diarrhea after admission. None were hypoxic, and the chest radiograph was normal in all five in whom this was performed. Empiric intravenous antibiotics were administered to six patients, but only one had a documented bacterial infection that involved the urinary tract. None of the five tested for other viral infections had a positive test.

COMMENTARY

The results of this study indicating relatively mild illness in young infants with COVID-19 are consistent with similar reports. This was true in the experience reviewed here despite evidence that the infants had a very high viral load. The RT-PCR cycle threshold (ct) is a reflection of the amount of virus present — low values, meaning fewer replication cycles are necessary for viral detection, are consistent with high viral loads. While the ct values of positive control samples in the testing in the presence of 1,000 copies per mL was 22.9 ± 0.4, the values for 14 of the infants ranged from 3.00-6.58, indicating very high viral loads.

COVID-19 testing must now be a part of the evaluation of infants with fever as well as various other symptoms suggestive of a possible infectious illness, including very subtle ones.