The Coronavirus 2019 (KOVID-19) pandemic continues to spread worldwide, resulting in over 59.17 million confirmed infections and over 1.39 million deaths. The causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), appeared in Wuhan, China, in December 2019.
Understanding the extent of the virus and its prevalence in the population is an essential part of limiting its spread. Therefore, accurate, efficient and accessible testing is key to implementing effective measures to socially distance ourselves, manage local epidemics and break the transmission chains.
Better testing may also help predict the severity of KOVID-19 in patients at the onset of their virus attack. Understanding the early probable prognosis of a patient with the disease by testing for high sensitivity may provide the necessary therapeutic interventions that will mitigate its impact on those vulnerable to more severe or critical cases.
Research laboratories work around the clock to develop better detection tests with high specificity and sensitivity. These tests were aimed at detecting neutralizing antibodies (NAbs) that block the spike-binding domain (RBD) of the SARS-CoV-2 glycoprotein (S) glycoprotein.
This binding to NAb-RBD blocks the virus protein from interacting with the human angiotensin-converting enzyme receptor 2 (ACE2), which is abundant in epithelial cells in the respiratory and intestinal tracts, the means by which the virus enters the host cell. .
Early humoral immune response to SARS-CoV-2 may predict clinical outcome (recovery, severity, or mortality). However, due to the lack of highly sensitive serological testing methods during the key early days of infection, this speculation has not yet been fully investigated.
In a recent print paper published on medRxiv * server, researchers in New York, USA, found an association of mortality with an early humoral response to SARS-KOV-2 infection in the first few days after onset of symptoms (DAOS), using highly sensitive and automated a-probe (TOP) biosensory testing SARS-CoV-2 assays.
The researchers report two sensitive and automated TOP biosensory assays for virus-specific SARS-KOV-2 antibodies (TAb) and surrogate neutralizing antibodies (SNAb). Competitive binding assay detects SARS-CoV-2 viral specific total antibodies (TAb) and surrogate neutralizing antibodies (SNAb) using an RBD-coated quartz probe.
Cy5-streptavidin polysaccharide conjugate is also used to improve sensitivity and minimize all disturbances.
The total analysis time is 16 min. The researchers also designed the assay with disposable cartridges containing previously released reagents, which means that it does not require manipulation of liquids or fluids during testing.
The researchers tested the clinical utility of the biosensor by assessing early antibody responses in the real-time polymerase chain reaction (RT-PCR) KOVID-19-positive hospitalized patients. The study group included 120 adult patients who were hospitalized at New York Presbyterian / Weil Cornell Medical Center (NYC) from March 8 to April 7, 2020.
The severity of KOVID-19 has been observed with varying results, leaving physicians, health care providers, and researchers without a trace of a possible outcome during treatment or hospitalization of patients. The differences in the studies so far depend on various factors.
For the first time, researchers demonstrated in this study that SARS-CoV-2 TAb and SNAb (at initial presentation) are risk indicators for in-hospital mortality. This study uses TOP analysis to link the antibodies present on the first day of hospital visit and subsequent mortality.
Probability of survival in SARS-CoV-2 infected patients with positive and negative (A) TOP-TAB and (B) TOP-SNAb at the initial presentation of ED in hospital. Data were analyzed using regression adjustment of Cox proportional hazards for age and cancer comorbidity.
The researchers found that patients who did not show high antibodies during a hospital visit had a higher risk of in-hospital mortality. Early after infection, NAbs, if present, avoid severe disease – by limiting the number of host cells that become productively infected.
They show that higher levels of antibodies are associated with lower viral load.
Their findings are in line with recent reports that early immune protection is important in patients with KOVID-19. These antibodies, which appear early in the infection phase, may be presumed to protect the patient from the severity of the infection and mortality; either by directly playing a protective role or by indirectly suppressing the replication of SARS-CoV-2.
A reliable and versatile serological test or antibody test detects infection early. This type of test is not yet available on the market.
This study reports on a new, fast, highly sensitive and fully automated biosensor (TOP) technology that can be adapted to the clinical laboratory environment. New tests reveal early antibodies to SARS-KOV-2 on the first day of a hospital visit. The findings show that the SARS-KOV-2 antibody level is inversely related to the subsequent KOVID-19 mortality.
The associations between early antibody response to SARS-CoV-2, initial viral load, and eventual hospital survival are consistent with strong, early humoral immunity, as opposed to SARS-CoV-2 replication — this may have significant management implications. with their immediate and future care.
Researchers believe that future studies will explore whether these new sensitive and specific assays can potentially monitor the effectiveness of antiviral therapies and assess antibody responses during vaccine trials.
* Important note
medRxiv publishes preliminary scientific reports that are not reviewed by the reviews and therefore should not be considered convincing, conduct clinical practice / health-related behavior, or be treated as established information.