Compared with the widely used antibody test, a new type of test can more effectively determine whether someone already has coronavirus.
The test looks for immune cells called T cells, which are white blood cells that bind and kill viruses.
A recent study by Seattle-based manufacturer Adaptive Biotechnologies found that the test is eight times higher than commercially available antibody tests in detecting past COVID-19 infections.
Immunologists said that pre-press research still requires peer review, but the results look promising and can replace antibody testing to find out how widespread the virus has spread in the community.
A new type of test looks for T cells (pictured), which can bind to and kill the virus to determine if anyone has been infected with the coronavirus in the past.
Among the 70 people with confirmed COVID-19 cases, T-cell testing correctly identified 97% of the cases, and antibody testing correctly identified 77% of the cases.Pictured: Medical staff treating patients with coronavirus in the COVID-19 ICU at the Joint Memorial Medical Center in Houston, Texas, November 2020
When someone is exposed to a virus, different parts of the immune system are needed to fight the virus, including antibodies and other immune cells.
Most attention is focused on antibodies, because testing them is fast and cheap. But over time, they usually decrease.
Dr. Akaki Iwasaki, an immunologist at Yale University School of Medicine, told CNN: “The source of the antibodies-the factory where they are made-died within a few months.”
On the other hand, recent studies have found that T cells may be sufficient to provide protection against viruses.
For other viruses, they have been shown to last for many years. Iwasaki said that we don’t know how long these viruses will last, but we can expect at least a few years.
A study published in the UK on Tuesday, A study conducted by Oxford Immunotec and Public Health England found that participants who did not have a high T cell response developed symptoms when infected with COVID-19.
In contrast, low Experience a T cell response with fever, cough or shortness of breath.
However, isolating T cells is very time-consuming, because thousands of T cells can recognize different molecules, and scientists must identify 20 or 30 cells that recognize coronavirus.
After the immune cells are separated from the blood sample, the cells are washed and counted.
Everyone is exposed to fragments of the virus to see which ones are immune to it.
For research that has not been published and is not funded by Adaptive, the team studied a sample of 2,200 people from Vo in Italy, which has become the center of its Veneto pandemic.
Among the 70 confirmed cases of the coronavirus, a test called T-Detect correctly identified 97% of the cases and only missed two of them.
In contrast, a commercial antibody test called DiaSorin can only correctly identify 77% of cases, of which 16 were missed.
This means that the test is eight times more effective in determining whether someone has previously been infected with COVID-19.
More importantly, out of more than 2,000 people who tested negative for the virus, the T-cell test returned positive results for 45 people.
The co-author of the paper, Dr. Lance Baldo, the Chief Medical Office of Adaptive, told CNN that most of these 45 people have never realized that they have been infected.
About half of them have mild symptoms or live with people who have tested positive for COVID-19, or both.
Adaptive said it plans to submit an emergency use authorization (EUA) application to the US Food and Drug Administration this month.