Table 2.

Persistence of SARS-CoV-2 in children

	Country	Sample size	Age	Sex	Diagnosis of COVID-19 complication	Baseline severity of COVID-19	Biopsy or autopsy	Organs analysed	Findings	Time between the acute infection and biopsy or autopsy	Evidence of virus, viral fragments, or antibodies
Taweevisit et al (2022)27	Thailand	1	5 years; 7 months	Male	MIS-C	Asymptomatic	Autopsy	Heart, lungs, kidneys, liver, stomach, intestine, and brain	Viral particles detected in heart, kidney, and intestine	2 months and 15 days	Viral RNA
Dolhnikoff et al (2020)28	Brazil	1	11 years	Female	MIS-C	Not reported	Autopsy	Heart, lungs, kidney, liver, stomach, brain, inguinal lymph nodes, muscle, and skin	SARS-CoV-2 RNA detected on a post-mortem nasopharyngeal swab and in cardiac and pulmonary tissues by RT-PCR by use of primers and probes set for E (envelope) gene 2	Not reported	Viral RNA
Duarte-Neto et al (2021)26	Brazil	3	8–12 years	2 female, 1 male	MIS-C	Not reported	Autopsy	Lung, heart, liver, kidneys, spleen, brain, bone marrow, colon, skin, and muscle	RT-PCR for SARS-CoV-2 positive in lung and heart of patient 1; intestine and parotid of patient 2; viral particle detected in cardiomyocytes of patient 3	Not reported	Viral RNA
Mayordomo-Colunga et al (2022)29	Spain	1	12 years	Male	MIS-C	Asymptomatc	Autopsy	Intestine, heart, lungs, and pericecal lymph nod	Spike protein detected by immunofluorescence in intestine	6 weeks	Spike protein
Sigal et al (2022)30	USA	3	Not reported	Not reported	MIS-C	Not reported	Blood sample	Blood	Antigens detected in 3 (5·7%) of 53 samples	>2 weeks	Antigen N or S
Arostegui et al (2022)31	USA	1	11 years	Female	Long COVID	Mild	Colonscopy	Intestine	SARS-CoV-2 nucleocapsid proteins detected in the intestinal lamina propria	3 months	SARS-CoV-2 nucleocapsid proteins
Scottoni et al (2022)32	Multinational	2	1 month; 5 months	1 male, 1 female	Intussusception	Mild	Biopsy	Lymph node and Ileum	Immunofluorescence staining revealed the presence of SARS-CoV-2 in both the mesenteric lymph node from patient 1 and ileum from patient 2	5 days	Virus
Colmenero et al (2020)33	Spain	7	11–17 years	4 males; 3 females	Chiblains	Asymptomatic or mild	Biopsy	Skin of the toes	Cytoplasmic granular positivity for SARS-CoV-2 spike protein shown in endothelial cells of the capillary and postcapillary venules of the upper dermis, and in epithelial cells of the secretory portion of eccrine units in all cases	4–30 days	Spike protein
Miura et al (2022)35	Brazil	48	Not reported	Not reported	Asymptomatic	Asymptomatic	Tonsillectomy	Tonsils and adenoids	SARS-CoV-2 genome detection rate was 20% in the tonsils, 16·27% in the adenoids, 10·41% of nasal cytobrushes, and 6·25% of nasal washes. IHC confirmed the presence of SARS-CoV-2 nucleoprotein in 15 of 16 positive tonsils samples, both in epithelium and lymphoid compartment	Not reported	Viral RNA
Araùjo et al (2021)34	Brazil	1	17 years	Female	Guillain-Barrè syndrome	Mild	CSF	CSF	SARS-CoV-2 RNA in CSF	8 days	Viral RNA
Xu et al (2022)36	USA	110	1·7–21 years	Female	No complication	Asymptomatic or mild	Biopsy	Tonsils and adenoids	Pharyngeal tissues from COVID-19-convalescent children showed persistent expansion of germinal centre and antiviral lymphocyte populations associated with interferon-γ-type responses, particularly in the adenoids, and viral RNA in both tissues	25–303 days	Viral RNA

IHC=immunohistochemistry. MIS-C=multisystem inflammatory syndrome in children. CSF= cerebrospinal fluid.