Asymptomatic SARS-CoV-2 Infection in Children’s Tonsils: A Hidden Reservoir?

A study published in the Brazilian Journal of Otorhinolaryngology provides intriguing insights into the asymptomatic presence of SARS-CoV-2, the virus causing COVID-19, in children’s tonsils and adenoids, suggesting these tissues as potential reservoirs for the virus.

Key Findings of the Study:

  1. Study Group: The research focused on 48 children who underwent adenotonsillectomy between October 2020 and September 2021. Notably, none of these children had shown signs or symptoms of acute upper airway infection in the month leading up to the surgery.
  2. Detection of SARS-CoV-2: The study employed a combination of RT-PCR, immunohistochemistry (IHC), flow cytometry, and neutralization assay techniques. It found that SARS-CoV-2 was detected in at least one sample from 12 patients, accounting for 25% of the study group. The rate of SARS-CoV-2 genome detection was 20% in the tonsils, 16.27% in the adenoids, 10.41% in nasal cytobrushes, and 6.25% in nasal washes.
  3. Tissue Analysis: Immunohistochemistry confirmed the presence of the SARS-CoV-2 nucleoprotein in 15 out of 16 positive tonsil samples, both in the epithelial and lymphoid compartments.
  4. Cellular Infection Patterns: Flow cytometry revealed that CD123+ dendritic cells were the most frequently infected cell type, followed by CD14+ monocytes, CD4+ T lymphocytes, CD20+ B lymphocytes, and, to a lesser extent, CD8+ T lymphocytes.
  5. Potential Reservoir for SARS-CoV-2: The study suggests that tonsils and adenoids could be significant sites of SARS-CoV-2 infection in asymptomatic children. The positive immunostaining in adenotonsillar tissue samples indicates that these lymphoid tissues might serve as reservoirs of the virus, playing a crucial role in community dissemination.
  6. Unanswered Questions: The duration for which the lymphoid tissue can sustain the SARS-CoV-2 virus in a state of persistent infection and the implications of this persistence on virus transmission remain unclear and warrant further investigation.

Conclusion:

This study sheds light on the asymptomatic presence of SARS-CoV-2 in children’s tonsils and adenoids, raising important questions about the potential role of these tissues in harboring and spreading the virus. It emphasizes the need for more research to understand the implications of such hidden reservoirs of SARS-CoV-2, especially in the context of community transmission and pandemic control strategies.

Read More: https://www.sciencedirect.com/science/article/pii/S1808869422001392

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