Dynamics and Determinants of SARS-CoV-2 RT-PCR Testing on Symptomatic Individuals Attending Healthcare Centers during 2020 in Bahia, Brazil.
Felicidade Mota PereiraAline Salomão de AraujoAna Catarina Martins ReisAnadilton Santos da HoraFrancesco PinottiRobert S PatonCamylla Vilas Boas FigueiredoCaroline Lopes DamascenoDaiana Carlos Dos SantosDaniele Souza de SantanaDanielle Freitas SalesEvelyn Ariana Andrade BrandãoEverton da Silva BatistaFulvia Soares Campos de SousaGabriela Santana MenezesJackeline Silveira Dos SantosJaqueline Gomes LimaJean Tadeu BritoLenisa Dandara Dos SantosLuciana ReboredoMaiara Santana SantosMarcela Kelly Gómez AsteteMarcia Freitas da CruzMariana Rosa AmpueroMariele Guerra Lemos da SilvaMariza S da Paixão MeloMarta Ferreira da SilvaNadja de Jesus Gonçalves Dos SantosNúbia de Souza PessoaRamile Silva de AraujoTaiane de Macedo GodimStephane Fraga de Oliveira TostaVanessa Brandão NardyElaine Cristina FariaBreno Frederico de Carvalho Dominguez SouzaJessica Laís Almeida Dos SantosPaul WikramaratnaMarta GiovanettiLuiz Carlos Junior AlcantaraJosé LourençoArabela Leal E Silva de MelloPublished in: Viruses (2022)
RT-PCR testing data provides opportunities to explore regional and individual determinants of test positivity and surveillance infrastructure. Using Generalized Additive Models, we explored 222,515 tests of a random sample of individuals with COVID-19 compatible symptoms in the Brazilian state of Bahia during 2020. We found that age and male gender were the most significant determinants of test positivity. There was evidence of an unequal impact among socio-demographic strata, with higher positivity among those living in areas with low education levels during the first epidemic wave, followed by those living in areas with higher education levels in the second wave. Our estimated probability of testing positive after symptom onset corroborates previous reports that the probability decreases with time, more than halving by about two weeks and converging to zero by three weeks. Test positivity rates generally followed state-level reported cases, and while a single laboratory performed ~90% of tests covering ~99% of the state's area, test turn-around time generally remained below four days. This testing effort is a testimony to the Bahian surveillance capacity during public health emergencies, as previously witnessed during the recent Zika and Yellow Fever outbreaks.