The importance of screening strategies in the management of the new coronavirus COVID-19
By Sergio A. Castañeda. BSc. Esp
Coronaviruses (CoVs) are a broad family of viruses that can cause a variety of illnesses, from the common cold to more serious complications, such as the Middle East respiratory syndrome coronavirus (MERS-CoV) and the one that causes respiratory syndrome. severe acute (SARS-CoV) (Padron-regalado, 2020).
A new coronavirus is a new strain of coronavirus that had not been found before in humans, as is the case with the cause of the current pandemic called SARS-CoV-2. The World Health Organization (WHO) has cataloged SARS-CoV-2, the cause of the disease called COVID-19, as a public health emergency of international importance, since cases have been identified on all continents, in addition to the first case in Colombia being confirmed on March 6.
However, great concern has been generated, among other things, by the high rate of transmission that this virus can have, which has allowed it to spread very quickly throughout the world and has focused global efforts on the search for strategies to control this transmission. Although mild and even moderate infections often lead to fever and respiratory symptoms (cough and dyspnea or shortness of breath), more severe cases can cause pneumonia, severe acute respiratory syndrome, kidney failure, and even death.
Additionally, various risk factors and complications associated with SARS-CoV-2 infection have been identified (Team, 2020). Therefore, public health interventions supported by the data provided by timely screening are transcendental to control and mitigate the impact that this virus is causing in the world population.
This information is not only important to identify positive cases for COVID-19, but also, with the aim of tracking contacts (contact tracing), which allows for containment and isolation activities in a timely manner, thus controlling potential transmissions.
TWO WAYS TO DIAGNOSE SARS-COV-2
Therefore, from the point of view of screening and diagnosis, there are two main methodologies: viral detection and antibody detection (proteins produced by the immune system in response to infections).
First, viral detection is carried out through molecular tests (RT-PCR) where the specific genetic material of the virus (Genes E, N and Rd-Rp) is identified using the so-called Berlin protocol (Zhang, Xie, & Hashimoto, 2020). This test is very helpful in identifying current infection cases.
Secondly, the detection of antibodies is carried out from serological tests (carried out in blood), which have shown the ability to detect said antibodies approximately 15 to 17 days after the onset of symptoms (Long et al., 2020 ).
Based on what has been described, screening strategies must be carried out fundamentally from viral detection since it allows the identification of cases during the first days of infection, even when they are asymptomatic, while serological tests can yield inconclusive results. at this time of infection, being useful for other purposes (Iwasaki & Yang, 2020).
It is clear that there is a need to implement massive screening in order to estimate levels of contagion and positive cases in geographic areas and specific populations affected by this virus in order to take specific measures. This targeting allows a better use of resources and has proven to be very effective in the so-called “flattening of the curve” as shown by countries such as Korea and Germany, where despite having a high number of positive cases, they maintain rates of minimal mortality thanks to the taking of measures with great impact and timely care.
It is clear that mass testing in the population, both symptomatic and asymptomatic, would allow to maintain better control of transmission and, likewise, provide timely medical attention to avoid collapses in the health system. However, there is great economic limitation in some countries to apply this type of strategy, which is why there is often a significant under-registration of infected subjects and thus insufficient information for proper decision-making.
In conclusion, it is essential to massify the screening tests for the identification of cases infected by SARS-CoV-2 and the strict follow-up of contacts, in order to have sufficient information for the adequate formulation of strategies. This information, together with the evaluation of the installed health capacity that a region has and other epidemiological data, will allow the making of public health decisions that can have a great impact in the search to control and mitigate the damage caused. by this virus while developing an effective treatment and a vaccine that allows to definitively manage this infection.
Sergio Andrés Castañeda Garzón. BSc. Esp.
Operations coordinator. CAIMED
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