Adjust the interface to make it easier to use for different conditions.
This renders the document in high contrast mode.
This renders the document as white on black

The dissemination of the Omicron variant in the highly seroprevalent Amazonas state, Brazil, is associated with a rapid upsurge of SARS-CoV-2 cases

Two exponential COVID-19 epidemic waves heavily hit the Brazilian state of Amazonas in early 2020 and early 2021, driven by SARS-CoV-2 variants B.1 (mainly B.1.195 and B.1.1.28) and variant of concern (VOC) Gamma (P.1), respectively [1, 2]. The high prevalence of individuals with hybrid (natural or vaccine-induced) immunity in this Brazilian state [3-5] successfully limited the previous expansion of VOCs Gamma plus (P.1.[6] and Delta (B.1.617.2/AY.[7] that emerged and spread during the second half of 2021 in the Amazonas. Consequently, the virus circulated at a roughly steady-state level of ~50-500 SARS-CoV-2 positive cases per day (7-day rolling average) from early May to late December 2021 [8]. In January 2022, however, the mean daily number of SARS-CoV-2 positive cases in the Amazonas rapidly increased from ~90 to ~6,500, coinciding with the global spread of the immune escape VOC Omicron (B.1.1.529/BA.*) [9].To follow up the most recent evolution of the SARS-CoV-2 in the Amazonas, we sequenced the virus genome from 1,260 patients (707 female, median age 36, IQR 26-47 and 553 male, median age 37, IQR 28-51), collected between 1st December 2021 and 17th January 2022, representing 2.9% of all laboratory-confirmed SARS-CoV-2 cases in the state in that period (n = 43,288) (Fig. 1). The Amazonas state health surveillance foundation and Central Laboratory from the State of Amazonas (LACEN-AM) sent SARS-CoV-2 positive samples from 27 out of 62 municipalities for sequencing at FIOCRUZ Amazônia, part of the local health genomics network (REGESAM) and the consortium FIOCRUZ COVID-19 Genomics Surveillance Network of the Brazilian Ministry of Health [10]. Most samples were from the capital Manaus (n = 926, 74%), followed by the Metropolitan region (n = 163, 13%) and interior municipalities from Central (n = 139, 11%), South (n = 23, 2%) and Southwest (n = 9, 1%) Amazonas regions (Fig. 2).

Categoria de assunto

Tipo de documento

Ano de publicação



  • Naveca, Felipe Gomes
  • Nascimento, Valdinete
  • Souza, Victor
  • Nascimento, Fernanda
  • Mejía, Matilde
  • Brandão, Maria Júlia
  • Silva, Arlesson Viana da
  • Silva, Dejanane
  • Silva, George
  • Gonçalves, Luciana
  • Ramos, Tatyana Costa Amorim
  • Castro, Daniel Barros de
  • Mattos, Tirza
  • Wallau, Gabriel Luz
  • Delatorre, Edson
  • Arantes, Ighor
  • Siqueira, Marilda Mendonça
  • Resende, Paola Cristina
  • Gräf, Tiago
  • Bello, Gonzalo