Unlocking the keys to mild COVID-19 cases in infants

Infants may have an edge over adults, with babies demonstrating a stronger immune response to the SARS-CoV-2 virus.

A new study¹ found that young infants have relatively higher antibody levels to the virus compared with adults and these antibodies can protect them against COVID-19, according to Anu Goenka, BSc, MBChB, clinical lecturer, and colleagues from the University of Bristol and Bristol Royal Hospital for Children, Bristol, UK.

Physicians have been observing that children do not seem to become as sick as adults when infected with COVID-19 during the pandemic and, in reality, have had mild cases.

This has been especially surprising since infants can become severely ill from respiratory syncytial virus and influenza.

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Considering this observation, Goenka and colleagues investigated the antibody and convalescent cellular immune responses to COVID-19 in 4 infants younger than 3 months old with mild disease compared with the parents and adult controls.

The investigators reported that the “infants have high serum levels of IgG and IgA to SARS-CoV-2 spike protein with corresponding functional ability to block SARS-CoV-2 cellular entry” compared with the adults.

This immune response, the investigators noted, appeared distinct from that of the parents.

The study also found that the infants had robust saliva anti-spike IgG and IgA responses. The spike-specific interferon (IFN)-γproduction by the peripheral blood mononuclear cells in the infants seemed restrained, but the frequency was similar to adults.

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The study data suggested that robust functional antibody responses and the restrained IFN-γproduction may be the keys to the protection against severe COVID-19 in these infants.

Goenka said that this information can help in the design of future COVID-19 vaccines.

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Reference

1. Goenka A, Halliday A, Gregorova M, et al. Young infants exhibit robust functional antibody responses and restrained IFN-γ production to SARS-CoV-2. Cell Reports Medicine Published June 9, 2021; Accedded June 13, 2021; DOI: https://doi.org/10.1016/j.xcrm.2021.100327