SPATIAL AND EPIDEMIOLOGICAL MONITORING OF SARS-CoV-2
INFECTION IN A REGION OF THE COLOMBIAN TROPICS
..................
Misael
Oviedo ¹
, Héctor Serrano-Coll ²
, Salim Mattar ³
Abstract
The
control of SARS-CoV-2 infection is one of the main challenges for
health authorities worldwide,
and one of the strategies for its control would be to delve into the
geospatial dynamics of this infection.
The objective of this research was Describe the geospatial and
epidemiological dynamics of SARSCoV-2 infection in the department of
Córdoba. Between March 2020 and July 2021, a prospective
descriptive study was carried out on the Spatio-temporal dynamics of
the infection by SARS-CoV-2 in
the department of Córdoba, area of the Colombian Caribbean. The
information in the data of cases
confirmed by SARS-CoV-2 of the National Institute of Health (INS) of
Colombia and the sociodemographic database of the national statistics
department was used. Our data show that SARS-CoV-2
spread throughout the department of Córdoba. The highly populated
clusters of the region were the
most affected. The age variable mainly explains the mortality rate in
the department (p <0.05, OR 18).
Finally, Control the infection, and it is essential to monitor and
predict the geographic areas with the
highest risk of SARS-CoV-2 infection to implement public health
strategies to reduce morbidity and
mortality
Palabras clave: Surveillance; Public Health; COVID-19;
Epidemiology; General Social Development; Population.
..............
¹ MD,
Master en investigación social en salud, PhD en Bioética, ética
aplicada y salud colectiva. Consultora del Fondo de Población
de Naciones Unidas. Profesora de derecho a la salud, Universidad de los
Andes.
² Instituto Colombiano de Medicina Tropical-Universidad CES,
Medellín, Colombia.
³ Universidad de Córdoba, Instituto de Investigaciones
Biológicas del Trópico, Montería, Colombia.
MONITOREO ESPACIAL Y EPIDEMIOLÓGICO DE
LA INFECCIÓN
POR SARS-CoV-2 EN UNA REGIÓN DEL TRÓPICO COLOMBIANO
Resumen
El control de la infección por SARS-CoV-2 es uno de los principales
desafíos para las autoridades sanitarias a nivel mundial, y una de las
estrategias para su control sería profundizar
en la dinámica geoespacial de esta infección. El objetivo de esta
investigación fue describir la
dinámica geoespacial y epidemiológica de la infección por SARS-CoV-2 en
el departamento
de Córdoba. Entre marzo de 2020 y julio de 2021 se realizó un estudio
descriptivo prospectivo sobre la dinámica espacio-temporal de la
infección por SARS-CoV-2 en el departamento
de Córdoba, zona del Caribe colombiano. Se utilizó la información de
los datos de casos
confirmados por SARS-CoV-2 del Instituto Nacional de Salud (INS) de
Colombia y la base de
datos sociodemográfica del departamento nacional de estadística.
Nuestros datos muestran
que el SARS-CoV-2 se extendió por todo el departamento de Córdoba. Los
conglomerados densamente poblados de la región fueron los más
afectados. La variable edad explica
principalmente la tasa de mortalidad en el departamento (p<0.05, OR
18). Finalmente, para
controlar la infeccion es fundamental monitorear y predecir las áreas
geográficas con mayor
riesgo de infección por SARS-CoV-2, e implementar estrategias de salud
pública para reducir
la morbilidad y la mortalidad.
Key words: Vigilancia; salud pública; COVID-19;
epidemiología; desarrollo social general;
población.
Highlights
- The variables sex, age, and UBN explain the fatality in this
region.
- In 2021 the highest peak of cases is likely related
to the entry of variants of interest such as Mµ,
Gamma, and Iota.
- The public health efforts should focus on vaccination in hot
spots and vulnerable populations to
limit the expansion and reduce the damage caused
by SARS-CoV-2.
Introduction
The control of the SARS-CoV2 infection has been the
main problem of the scientific and health community
in the last year since this new infection has become
the main challenge in public health for health systems
around the world. SARS-CoV-2 has caused more
than 420 million reported infections and the death of
more than 5.8 million people worldwide (1). One of
the strategies for controlling SARS-CoV-2 is to know
the geospatial dynamics of the infection, which would
allow us to understand the failures when facing the
waves of SARS-CoV2.
On the other hand, in 2020, our research group studied the dynamics of
this infection in the department
of Córdoba, evaluating through serological tests the
presence of total antibodies against the SARS-CoV-2
nucleocapsid protein in the most representative municipalities. from
this department showing high seropositivity (41%) in this region (2).
However, serology does
not show real-time viral mobility and spatial distribution of human
clusters infected with SARS-CoV-2.
Currently, the location of the affected populations is
crucial to understand the geographic areas most susceptible to new
waves of infection.
Therefore, the
analysis of geolocation data, clinical and sociodemographic information
of the cases confirmed by SARSCoV-2 of the department are crucial to
understanding
the dynamics of the infection.
Therefore, the objective of this work was to describe
the geospatial and epidemiological dynamics of
SARS-CoV2 infection in the department of Córdoba,
Colombia.
Methodology
Between March 2020 and July 2021, a prospective
descriptive study was carried out on the Spatiotemporal dynamics of
SARS-CoV-2 infection in the
department of Córdoba. The department is located
in the North-West of Colombia in an area of the
Colombian Caribbean. The information consigned
in the database of cases confirmed by SARS-CoV-2
and their severity of the National Institute of Health
(INS) of Colombia (1)( and the sociodemographic
database of the National Administrative Department
of Statistics (DANE) were used (2). The severity of
the disease criteria used by INS and the Colombian
Association of Infectious Diseases (ACIN) (3,4) were
followed: a) Mild disease: local symptoms in the upper respiratory
tract and may present with nonspecific symptoms such as fever, muscle
pain, or general
malaise. b) Moderate disease: clinical or radiological
evidence of lower respiratory infection, with compatible lung images
and O2 saturation> 93%. c) Severe
disease: respiratory rate greater than 30 / min, oxygen saturation
<93%, PAFI (the relationship between
arterial oxygen pressure and the inspired fraction of
oxygen (PaO2 / FiO2) less than 300, infiltrates more
than 50%.
The integration of the two databases made it possible
to relate (cases / 100,000 inhabitants) and compare
the casuistry between the different municipalities. Additionally, it
was possible to integrate the index of unsatisfied basic needs (UBN)
(5), an official indicator
representing each municipality’s main socio-economic
aspects in Colombia.
Risk factors associated with mortality and trends in
the geographic distribution of the cases were analyzed.
Through a logistic regression model, mortality from
COVID-19 was analyzed with the variables sex, age,
and UBN. The continuous variables (age and UBN)
were transformed into category variables, which were
established as high and low, the respective means were
used as a cut-off point.
An epidemic curve was constructed with confirmed
cases and the number of deaths in the department of
Córdoba and its capital Montería. Data were aggregated as
epidemiological weeks during the study period.
Additionally, the leading social events that could affect
the behavior of the pandemic were analyzed, such as
Easter, days without VAT, end-of-year holidays, and
the first four stages of the vaccination plan.
Finally, two epidemiological maps were constructed
with the distribution of the infection during the pandemic. The kernel
density estimator (6) was used on
the cases of each municipality, and it was related to
the population (cases / 100000 inhabitants/municipalities). A bandwidth
of 40 km was used, and the QGIS
program, version 3.4.
Results
Until July 23, 2021, in the department of Córdoba,
97,534 cases of COVID-19 were reported, of which
53,130 (54.5%) were in women, and 44,404 (45.5%)
were men. The mean age was 41.3 years (95% CI, 41.1
to 41.4). Two thousand eighty-three men died, which
produced a high fatality of 4.7%. In contrast, the fatality in women
was lower, with 1.375 (2.6%) deaths. The
average NBI was 26.9% (95% CI, 26.9 to 27.0), and the
average of each case in the department was 1.18 cases
/ 100,000 inhabitants (95% CI, 1.17 to 1.19).
When analyzing the cases in each municipality, it was
observed that Montería, the department’s capital, was
the city with most cases 51,803 (53.11%). The other municipalities with
the most cases of SARS-CoV-2 in their
order were: Cerete, Sahagún, Chinú, Cotorra, Pueblo
Nuevo, Ciénaga de Oro, Lorica, Canalete, Montelíbano, Momil, San Pelayo
and Planeta Rica (Table 1).
Table 1. Sociodemographic characteristics of SARS-CoV-2 infection
in the Cordoba.
When comparing the average ages with the different
forms of the severity of COVID-19 reported by the
INS, a statistically significant difference was observed
(p <0.0001), the group of individuals who died had
an average of 67.7 years. In contrast, the mild forms
of the disease had an average age of 40.1 years. Furthermore, no
differences were observed in the mean
age between individuals with severe (48.3 years) and
moderate (48.6 years) forms of this disease (p> 0.05).
(Table 2).
On the other hand, when evaluating the gender variable, a higher
infection was observed in women (n =
53,130) than in men (n = 44,404). However, in men,
the fatality rate was significantly higher than in women
(p <0.0001) (Tables 1 and 2).
Variable’s sex, age, and UBN vs. the risk of death to
explain the fatality in the department of Córdoba were
analyzed. It was observed in the univariate and bivariate analysis that
age was strongly associated with mortality in the department. These
data allow us to infer
that the department’s risk of dying increases 18 times
(Tables 3, 4).
The epidemic curve for the department of Córdoba
and the municipality of Montería shows the confirmed
cases of SARS-CoV-2 and the number of deaths observed and expected
during the pandemic peaks of the
years 2020-2021 (Figure 1). Regarding the confirmed
cases of SARS-CoV-2, the first wave of cases in this
department began in week 25. The maximum peak
was reached in week 31 of 2020. The week coincided
with the commercial opening of the day without VAT.
Subsequently, a decrease in cases was observed between weeks 36 and 50
of 2020. In week 51, there was
a new commercial opening that coincided with the end
of the year festivities, and from this week, a new increase in the
number began of COVID-19 cases, which
remained constant during the first quarter of 2021. In
week 6 of the quarter, the vaccination plan against
SARS-CoV-2 began. From week 12 (Holy Week), exponential growth in the
number of cases was observed
until the maximum peak of reported cases of SARSCoV-2 in week 25. Later
a significant decrease in cases
was observed between weeks 26 -28 (Figure 1).
Regarding fatality in the department, a lower rate
was observed in the peak of 2021 compared to 2020.
When comparing the expected fatality rate in the
second epidemic peak in 2021 compared to that observed in 2021,
differences were observed between
the expected lethality (n = 4,130) and observed (n =
1,741) (Figure 1).
Table 2. Relationship between age and gender with the outcome of
SARS-CoV-2 infection.
a,c: Statistical significance, b: Non-statistical significance.
Table 3. Univariate analysis of variables associated with mortality
from COVID-19 in Cordoba, Colombia.
CI: Confidence interval, UBN unsatisfied basic needs.
Table 4. Multivariate logistic regression model for mortality from
COVID-19 in Cordoba, Colombia.
CI: Confidence interval, * No apply.
Figure 1. Curve in epidemiological weeks of cases and deaths
confirmed by SARS-COV-2, in the department of
Córdoba, 2020-2021. Cases are represented on the Y-axis and deaths on
the right axis. Social events that could
influence the behavior of the infection were added: + Easter, $ day
without VAT, * end of the year, and V vaccination
plans. In 2021, the number of expected deaths is observed at the second
peak.
Figure 2. Monthly geographic distribution of Sar-CoV-2 infections
in the department of Córdoba, Colombia, 2020 to
July 2021. The Kernel density estimator was used for a high case
density in Montería, the department’s capital, and
neighboring municipalities.
Regarding the geospatial distribution of the SARSCoV-2 infection, the
cases were concentrated in Montería and nearby municipalities such as
Cereté (Figure
2). It was observed that the infection spread from
Montería to the north of the department, affecting
many municipalities (Cereté, San Carlos, San Pelayo,
Cotorra, Lorica, Chima, Purísima, Momil, San Antero, Sahagún and
Chinú).
Discussion
Our data show that SARS-CoV-2 spread uncontrollably throughout the
department of Córdoba, a situation
that could be influenced by the predominant informal
economy in the region studied (7) and for cultural reasons. For this
reason, a high rate of infection by this
new coronavirus was observed in both men and women. However, in men,
the clinical evolution was worse
than in women, which could be explained at the level
of their lung cell membranes where there is a greater
expression of serine proteases (TMPRSS2), which
promote the cleavage of the Spike (S) protein (8)inflammatory
cytokines, disease severity, and poor clinical outcomes among male
patients with COVID-19.
The gradual decline in total and free testosterone levels
has a direct correlation with serious pulmonary complications requiring
advanced care (ICU, ventilators,
ECMO, etc.. This mechanism would induce a higher
viremia in men, which would trigger an exacerbation
of their innate and adaptive immune response, thus
generating inflammation, tissue damage, and a worse
clinical evolution in men.
Regarding the region’s mortality rate, our analyses indicate that age
behaves as a risk factor for mortality in
the department of Córdoba. This would be related to the loss of innate
and adaptive immune function due
to aging (immune-senescence), which compromises its
protection against infectious agents such as this new
coronavirus (9). Concerning fatality in older adults
in the department of Córdoba, previous studies have
shown that older adults have a higher risk of complications and fatal
outcomes due to this infection (10,11).
Regarding the epidemic curve of the department of
Córdoba (Figure 1), it was observed that the SARSCoV-2 transmissibility
peaks in the year 2020-2021
were associated with activities that reduced self-care
measures and promoted the agglomeration of people,
such as the day without VAT, Easter and Christmas
holidays. In 2021 the highest peak of cases is likely
related to the entry of variants of interest such as Mµ,
Gamma, and Iota. These variants were related with
the increased of the transmission of the virus in the
department (12).
However, it is essential to note that despite having evidenced greater
transmissibility of this virus in the Cordoba population, the mortality
rate did not increase
and was lower than that observed in 2020. This could
be a consequence of two factors, the first being high
seropositivity (41%) product of the natural infection
against SARS-CoV-2 in the department of Córdoba
and its capital Montería (55%) (5). The second factor
would be the vaccination of this population against
this new coronavirus, currently the rate of fully vaccination at
Córdoba population is around 31% (13,14).
Therefore, the massive vaccination strategy must be
accelerated to avoid the viral circulation and rapid
transmission of concern variants of SARS-CoV-2 such
as Omicron and its sublineages (BA.1, BA.2).
On the other hand, the higher density of COVID-19
cases in Montería and its nearby urban municipalities
would be a consequence of the significant population
and commercial mobility towards the capital of the
department (Figure 2). This makes it challenging to
implement protective measures such as social distancing, which
facilitates the circulation of SARS-CoV-2.
Our results are similar to those of Yin et al.(15), who
demonstrated that the new coronavirus’s advancement
and speed of dissemination are related to urban areas
with higher population density.
In conclusion, it is crucial to control SARS-CoV-2
infection to continue describing and predicting the
geographic areas with the highest risk of infection
and thus implement public health strategies to reduce
the morbidity and mortality caused by this infection.
Based on the results obtained, it is critical to suggest
that public health efforts focus on buster vaccination
in hot spots and vulnerable populations to limit the
expansion and reduce the damage caused by the new
coronavirus.
Acknowledgments
To Ministerio de Ciencia Tecnología e Innovación,
Colombia (MINCIENCIAS), AGROSAVIA.
References
1.Instituto Nacional de Salud. Casos positivos de COVID-19
en Colombia.Bogotá: INS; 2021.
2. Departamento Administrativo Nacional de Estadística.
Censo Nacional de Población y Vivienda - CNPV 2018
[Internet]. 2018.[consultado 2 febrero 2022]. Disponible
en: www.dane.gov.co › censo2018 › CNPV-2018-VIHOPE-v2
3. Saavedra Trujillo C. Consenso colombiano de atención,
diagnóstico y manejo de la infección por SARS-COV-2/
COVID-19 en establecimientos de atención de la salud
Recomendaciones basadas en consenso de expertos e
informadas en la evidencia [Internet]. 2020.[consultado
2 febrero 2022]. Disponible en:http://www.revistainfectio.org/index.php/infectio/article/view/851/896
4. World Health Organization. Clinical management of
COVID-19 [Internet]. 2020.[consultado 2 febrero 2022].
Disponible en:https://www.who.int/publications/i/item/clinical-management-of-covid-19
5. Departamento Administrativo Nacional de Estadística.
Necesidades básicas insatisfechas (NBI) [Internet]. 2021. [consultado 2
febrero 2022]. Disponible en:
https://www.dane.gov.co/index.php/estadisticas-por-tema/pobreza-y-condiciones-de-vida/necesidades-basicas-insatisfechas-nbi
6. Kloog I, Hain B, Portnov B. Using kernel density function
as an urban analysis tool: Investigating the association
between nightlight exposure and the incidence of breast
cancer in Haifa, Israel.Computers, Environment and Urban Systems.
2009;33(1):55–63.
7. Departamento Administrativo Nacional de Estadística.
Medición de empleo informal y seguridad social [Internet].
2021.[consultado 2 febrero 2022]. Disponible en:
https://www.dane.gov.co/files/investigaciones/boletines/ech/ech_informalidad/bol-geih-informalidad-abr21-jun21.pdf
8. Hussain AN, Hussain F, Hashmi SK. Role of testosterone in COVID-19
patients - A double-edged sword? Med
Hypotheses. 2020;144:110287.
9. Jergović M, Coplen CP, Uhrlaub JL, Nikolich-Žugich J.
Immune response to COVID-19 in older adults. J Heart
Lung Transplant. 2021 ;40(10):1082-1089.
10. Yanez ND, Weiss NS, Romand J-A, Treggiari MM. COVID-19 mortality
risk for older men and women. BMC
Public Health. 2020;20(1):1742.
11. García-Posada M, Aruachan-Vesga S, Mestra D, Humánez K,
Serrano-Coll H, Cabrales H, et al. Clinical
outcomes of patients hospitalized for COVID-19 and
evidence-based on the pharmacological management
reduce mortality in a region of the Colombian Caribbean.
J Infect Public Health. 2021;14(6):696–701.
12. Instituto Nacional de Salud. Distribución geográfica de
los linajes de SARS-CoV-2 circulantes en Colombia
[Internet]. 2021.[consultado 2 febrero 2022]. Disponible
en:
https://www.ins.gov.co/Noticias/Paginas/coronavirus-genoma.aspx
13. Our World in Data. Coronavirus (COVID-19) Vaccinations [Internet].
2022.[consultado 2 febrero 2022]. Disponible en: https://ourworldindata.org/covid-vaccinations
14. Ministerio de Salud Colombia. Plan Nacional de Vacunación contra
COVID-19 [Internet]. 2021. [consultado 2
febrero 2022]. Disponible en:
https://app.powerbi.com/view?r=eyJrIjoiNThmZTJmZWYtOW-FhMy00OGE1LWFiNDAtMTJm-YjM0NDA5NGY2IiwidCI6ImJmY-jdlMTNhLTdmYjctNDAxNi04-MzBjLWQzNzE2ZThkZDhiOCJ9
15. Yin H, Sun T, Yao L, Jiao Y, Ma L, Lin L, et al. Association
between population density and infection rate suggests
the importance of social distancing and travel restriction
in reducing the COVID-19 pandemic. Environ Sci Pollut
Res Int. 2021;28(30):40424.