BMC Infectious Diseases (Jan 2022)

SARS-CoV2 infection in symptomatic patients: interest of serological tests and predictors of mortality: experience of DR Congo

  • Jean-Robert Makulo,
  • Madone Ndona Mandina,
  • Placide Kingebeni Mbala,
  • Roger Dimosi Wumba,
  • Pierre Zalagile Akilimali,
  • Yannick Mayamba Nlandu,
  • Jerome Ossam Odio,
  • Ben Izizag Bepouka,
  • Murielle Mashi Longokolo,
  • Eric Kasongo Mukenge,
  • Guyguy Kamwiziku,
  • Jonathan Mutombo Muamba,
  • Augustin Luzayadio Longo,
  • Crispin Muanza Lufu,
  • Hervé Letin Keke,
  • Marcel Mambimbi Mbula,
  • Hippolyte Nanituma Situakibanza,
  • Ernest Kiswaya Sumaili,
  • Jean-Marie Ntuma Kayembe

DOI
https://doi.org/10.1186/s12879-021-07003-9
Journal volume & issue
Vol. 22, no. 1
pp. 1 – 9

Abstract

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Abstract Background In symptomatic patients, the diagnostic approach of COVID-19 should be holistic. We aimed to evaluate the concordance between RT-PCR and serological tests (IgM/IgG), and identify the factors that best predict mortality (clinical stages or viral load). Methods The study included 242 patients referred to the University hospital of Kinshasa for suspected COVID-19, dyspnea or ARDS between June 1st, 2020 and August 02, 2020. Both antibody-SARS-CoV2 IgM/IgG and RT-PCR method were performed on the day of admission to hospital. The clinical stages were established according to the COVID-19 WHO classification. The viral load was expressed by the CtN2 (cycle threshold value of the nucleoproteins) and the CtE (envelope) genes of SARS- CoV-2 detected using GeneXpert. Kappa test and Cox regression were used as appropriate. Results The GeneXpert was positive in 74 patients (30.6%). Seventy two patients (29.8%) had positive IgM and 34 patients (14.0%) had positive IgG. The combination of RT-PCR and serological tests made it possible to treat 104 patients as having COVID-19, which represented an increase in cases of around 41% compared to the result based on GeneXpert alone. The comparison between the two tests has shown that 57 patients (23.5%) had discordant results. The Kappa coefficient was 0.451 (p < 0.001). We recorded 23 deaths (22.1%) among the COVID-19 patients vs 8 deaths (5.8%) among other patients. The severe-critical clinical stage increased the risk of mortality vs. mild-moderate stage (aHR: 26.8, p < 0.001). The values of CtE and CtN2 did not influence mortality significantly. Conclusion In symptomatic patients, serological tests are a support which makes it possible to refer patients to the dedicated COVID-19 units and treat a greater number of COVID-19 patients. WHO Clinical classification seems to predict mortality better than SARS-Cov2 viral load.

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