Novel Coronavirus COVID-19 neutralising antibodies

Coronaviruses are the largest family of RNA viruses. They evolved over thousands of years with bats as their hosts, however, they can infect other species of animals as well as humans. In humans, coronaviruses can cause a variety of symptoms, ranging from a simple cold to severe acute respiratory syndrome type 2 (SARS).

In November 2019, a new human strain of the virus, SARS-CoV-2, was initially in the Chinese city of Wuhan. Its rapid spread worldwide prompted the World Health Organization (WHO) in March 2020 to declare a COVID-19 pandemic.

The antibody test is a rapid immunochromatographic flow test that detects molecular produced by the immune system in response to SARS-CoV-2 infection and helps identify people who have been infected relatively recently or in the past even if they are asymptomatic. Blood samples are used to carry out the antibody test, where the detection of three antibody types produced by the human body against the virus, IgA, IgG and IgM, takes place. IgM antibodies provide the first line of defence during the viral infection. IgA antibodies indicate a recent infection and are an indicator of a first immune response. IgG antibodies are essential for the development of long-term immunity.

Neutralising antibodies test

The neutralising antibody against SARS-CoV-2 acts against the binding region (S-RBD), the S (spike) glycoprotein of the surface of the virus, in the receptor of tissue cells of the human body. This test is ideal for evaluating the effect of he COVID-19 vaccine on the human body, as well as detecting neutralising antibodies in infected patients.

The double-antigen sandwich method used in this test increases the specificity and sensitivity of the simultaneous detection of IgA, IgG and IgM antibodies against S-RBD in the sample during the test. Increased IgA in the sample correlates with the severity of the disease.

The sensitivity of this test is approximately 98.55%, the specificity approximately 99.31% and the reliability close to 99.09%, making it ideal for mass screening of neutralizing antibodies after vaccination of a portion of the population.