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. 2021 Mar:104:572-579.
doi: 10.1016/j.ijid.2020.12.086. Epub 2021 Jan 9.

Epidemiology of COVID-19 in Mexico: Symptomatic profiles and presymptomatic people

Miguel A Fernández-Rojas  1 , Marco A Luna-Ruiz Esparza  1 , Abraham Campos-Romero  1 , Diana Y Calva-Espinosa  2 , José L Moreno-Camacho  3 , Ariadna P Langle-Martínez  4 , Abraham García-Gil  3 , Claudia J Solís-González  4 , Adrián Canizalez-Román  5 , Nidia León-Sicairos  6 , Jonathan Alcántar-Fernández  7
Affiliations

Epidemiology of COVID-19 in Mexico: Symptomatic profiles and presymptomatic people

Miguel A Fernández-Rojas et al. Int J Infect Dis. 2021 Mar.

Abstract

Objectives: The COVID-19 diagnosis is difficult and ambiguous due to nonspecific symptoms. Further, data from Mexico arehospitable population-based without signs and symptoms information. Thus, this work aims to provide epidemiology information about the burden of COVID-19 in Mexican outpatients and to identify symptomatic COVID-19 profiles that could help in the early diagnosis of the disease.

Methods: From June to September, epidemiological, clinical, and demographic data of 482,413 individuals diagnosed by RT-PCR test for SARS-CoV-2 in Salud Digna clinics were collected.

Results: We observed a 41% incidence of SARS-CoV-2 infections with a mean age of 36 years and with young adults (20-40 years) being the most affected. Among occupations, delivery persons (OR 1.38) or informal traders (OR 1.33) had a higher risk of COVID-19. Moreover, 13% of SARS-CoV-2 infections were in presymptomatic patients. Finally, we identified three different symptomatic profiles (common, respiratory, and gastrointestinal) associated with COVID-19.

Conclusion: The incidence of SARS-CoV-2 was high among outpatients with a significant proportion of presymptomatic carriers, and thus it is necessary to increase testing and continue SARS-CoV-2 surveillance with a better description of signs and symptoms; in this regard, we identified three symptomatic profiles that could help in the diagnosis of COVID-19.

Keywords: COVID-19; Epidemiology; Mexico; Presymptomatic.

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Figures

Figure 1
Figure 1
Demographic and Clinical data summary. (A) Coropletic map showing the incidence rate of SARS-CoV-2 infections in 26 states of Mexico; the dark-blue color indicates the states with a high incidence of infections, while light blue shows the states with a low incidence. The gray color in the map shows the states not included in this work; (B) Temporal trend of SARS-CoV 2 positive cases from June 1st to September 30th; (C) Sex and Age distribution of SARS-CoV 2 cases (n = 196,738).
Figure 2
Figure 2
Standardized rate ratio (SRR) of SARS-CoV-2 infection in 26 states of Mexico, considering the general incidence as reference (1.0).
Figure 3
Figure 3
Tandem clustering analysis for COVID-19 related symptoms. Panel A shows the symptoms’ dispersion plot through main component analysis (MCA); the red color indicates the gastrointestinal cluster, gold shows the respiratory cluster, and blue shows the common cluster (no symptoms stand out). Dimension 1 (Dim 1) and Dimension 2 (Dim 2) shows the variance explained by each one (22.2 and 9.4%, respectively). Panel B shows the frequency and distribution of COVID-19 related symptoms in each cluster identified. Symptoms are indicated as 1 = Conjunctivitis, 2 = Abdominal pain, 3 = Headache, 4 = Sore throat, 5 = Myalgia/Arthralgia, 6 = Breath difficulty, 7 = Diarrhea, 8 = Chills, 9 = Fever, 10 = Runny nose, 11 = Constant dry cough, and 12 = Vomiting).
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