The test is based on non-structural proteins of the virus that had not been used in diagnosis and it detects with high specificity and sensitivity SARS-CoV-2 antibodies.
A new serological test for Covid-19 antibodies with a reliability close to 100% has been recently launched to the market, developed by researchers from the Spanish Council for Scientific Research (CSIC), in collaboration with the Madrid Hospitals of La Princesa and La Paz, and produced by the Spanish biotechnology company Immunostep. The test is based on a protein of the virus that had not been used in diagnosis before, this protein can act as an antigen to reveal the immune response against SARS-CoV-2 with a high proven accuracy.
These tests detect three types of antibodies and allows us to identify whether the system has been exposed to the SARS-CoV-2 virus. It is a very useful tool to identify individuals who have developed immune protection against coronavirus, and to design an efficient vaccination strategy for the population. Furthermore, this test is able to distinguish which people have generated a response to the vaccine from those who have been infected and respond to the virus.
The test is presented in an ELISA kit format and it has included all the needed reagents to reveal the presence of antibodies in the patient’s serum and plasma. It is performed in the laboratory and offers results in about two hours. “The main novelty of the test is that it is based on viral proteins that until now had not been used in diagnosis” explains Mar Valés, researcher at the National Center for Biotechnology of the CSIC (CNB-CSIC), who has co-led the research work.
Researchers have carried out a trial, published in the Journal of Immunology, showing that this test, combined with the detection of other commonly used coronavirus antigens, allows us to identify all the individuals who have developed immunity against coronavirus.
“The test is extremely sensitive, and the combination of a new antigen with the immunoglobulins IgG and IgA allows to detect antibodies practically from the onset of symptoms”, indicates Ricardo Jara, CEO of Immunostep. “Given its high sensitivity, we believe that it will be a very powerful tool at this stage of vaccination that we are starting to face” he adds.
“This test allows us to study the immune response of antibodies against the virus”, indicates Eduardo López, coordinator of the immunology department of the Hospital Universitario de La Paz, in Madrid. “It is possible to see the response to antibodies against more proteins than are usually included in most tests, including the finding of the CSIC group, which is this protein (protease)” he adds. “we believe this test is more versatile than others that are already available.”
There have been global efforts to manufacture effective diagnostic technologies which are the key for the monitoring of Covid-19, specifically, serological testing will be vital in monitoring antibody levels, and the immune response to the different vaccines.
Last data suggest that most people who recover from COVID-19 develop an immune response that provides some protection against reinfection, although there are still trying to discover how long it will last. For this reason, it is not clear how many doses of a Covid-19 vaccine will be needed, even though the most vaccines available are using two doses. In this sense, and looking at emerging data, patients are susceptible to second infections of Covid-19 after losing immunity. In this sernse, serology testing, which allows to quantify antibody levels, will be critical in monitoring these patterns.
Covid-19 pandemic has shown the importance of molecular reliable diagnostics, and we can analyze how countries that have developed early their testing resources and capability have managed the outbreak more successfully.
Serological surveys are essential for the next stage of the pandemic we are already facing. Throughout serological surveys we can look for antibodies against the SARS-CoV-2 virus in population groups, and the main objectives of these surveys are, firstly to learn how many people of that group have been exposed to the virus, and secondly, which of those groups are more exposed or have had higher rates of infections.
Additionally, the public health authorities will have an idea of how infection rates are progressing in a particular area. These tendencies will give us so much information about how the human immune system works against the SARS-CoV-2 virus, how long antibodies last and how long they protect us. These tests also give an opportunity to answer all those questions.