We show that low quality of all 427 Brazilian SARS-CoV-2 genomes recently published in Science (1) challenges their phylogenetic inference and may lead to incorrect typing of viral strains in clades with no statistical support. Absence of basecalling quality in genome assemblies and proper phylogeny parameter estimates preclude the assessment of signal-to-noise ratio in the data, downstream analysis and conclusions.

The Zika virus (ZIKV) epidemic brought new discoveries regarding arboviruses, especially flaviviruses, as ZIKV was described as sexually and vertically transmitted. The latter shows severe consequences for the embryo/fetus, such as congenital microcephaly and deficiency of the neural system, currently known as Congenital ZIKV Syndrome (CZS). To better understand ZIKV dynamics in trophoblastic cells present in the first trimester of pregnancy (BeWo, HTR-8, and control cell HuH-7), an experiment of viral kinetics was performed for African MR766 low passage and Asian-Brazilian IEC ZIKV lineages. The results were described independently, and demonstrated that the three placental cells lines are permissive and susceptible to ZIKV. We noticed cytopathic effects that are typical in vitro viral infection in BeWo and HTR-8. Regarding kinetics, MR766lp showed peaks of viral loads in 24 and 48 hpi for all cell types tested, as well as marked cells death after peak production. On the other hand, HTR-8 lineage inoculated with ZIKV-IEC exhibited increased viral production in 144 hpi, with a peak between 24 and 96 hpi. Furthermore, IEC had peak variations of viral production for BeWo in 144 hpi. Both cells types continued alive during the process of viral replication. Considering such in vitro results, the hypothesis that maternal-fetal transmission is probably a way of virus transmission between the mother and the embryo/fetus is maintained.