Fig. 1.

Initial SARS-CoV-2 RNA loads in nasopharyngeal specimens from unvaccinated individuals infected by either Alpha (B.1.1.7) or Delta (B.1.617.2) variants. The Alpha lineage was confirmed by whole-genome sequencing in 108 cases, whereas in the remaining 230 it was inferred by S-gene target failure (SGTF) in the RT-PCR, as more than 95% of SGTFs detected in the Clínico-Malvarrosa Health Department belonged to that lineage within the timeframe of specimen collection (not shown). The Delta lineage was confirmed by whole-genome sequencing (n = 138) or variant-specific RT-PCR (n = 61). Whisker-plots of SARS-CoV-2 RNA loads in NP by time of sampling relative to symptoms onset are displayed separately for adults (A) and children (B). Whisker-plots of SARS-CoV-2 RNA loads in NP for asymptomatic participants are also shown separately for adults (C) and children (D). P values are shown for comparisons across groups.