Extended Data Fig. 6: Saliva sampling supports a role for oral cavity in COVID-19 pathogenesis.

a,b, (a) Acellular (b) and cellular fractions (N = 8) were incubated with Vero cells in duplicate. Supernatants from the acellular saliva more often caused CPE (n = 2 of 8) compared to the cellular fraction (n = 1 of 8); 1 independent replication. c, A clinical study, NIH Transmissibility and Viral Load of SARS-CoV-2 Through Oral Secretions Study (AKA – ‘NIH Carline Study’), was used for symptom tracking and prospective sampling of nasopharyngeal (NP) swabs and saliva. d, Subjects with the highest saliva viral load and reported taste alterations (left); these individuals displayed infection of salivary epithelial (pCK⁺) cells using spike and polymerase probes--n = 3 (CoV19, CoV23, CoV25 where 2257, 28260, and 31804 cells, respectively, were counted). Bars are presented as mean + /- SEM., respectively with 1 independent replication). e, Infectious saliva fraction was measured with masks and unmasked in symptomatic (oral/systemic; red and systemic only; green). f, Sub-study of LIPS for nucleocapsid IgG and spike IgG levels comparing saliva and sera from the same subjects by calculating a two-sided agreement statistic (kappa) of antibody positivity without adjustment for multiple comparisons. Due to the limitations of the study design, samples were not temporally linked. In general, there was fair to excellent agreement between the presence of salivary and sera antibodies to nucleocapsid and spike, respectively. No pattern for salivary versus sera nucleocapsid IgG levels was observed, though this may reflect temporal differences. Sera trended toward relatively higher levels when assaying for spike IgG antibody levels. Green dotted lines in (f) represent saliva cutoff for nucleocapsid and spike; blue dotted lines, cutoffs for sera. Annotations: Scale bars: (a,b) 100μm, (d) 25μm. Statistical test (e): p < 0.005, two-sided Wilcoxon signed-rank test.