Many people have been in close contact, even living with Covid patients for a long time, but the test is still negative. A recently published study by scientists at University College London (UK) has explained why some people do not get infected with SARS-CoV-2 virus despite close contact with F0 patients.
Many people are in close contact with F0 but the test is still negative
According to published research results, the reason that some people do not become infected with the SARS-CoV-2 virus despite exposure to F0 may be due to the response of T cells - white blood cells that play an important role in the body's immune system.
Research has shown that some people do not become infected with SARS-CoV-2, possibly thanks to the response of T cells (the body's immune cells) from previous infections with cold-like corona virus.
Previous studies have shown that T cells that fight other coronaviruses can recognize SARS-CoV-2. However, it was not until this scientific work that showed that T cells affect the ability to become infected when a person is exposed to the SARS-CoV-2 virus.
"Exposure to the SARS-CoV-2 virus does not always lead to infection. We found that high concentrations of pre-existing T cells are produced by the body during infection. infection with other human coronaviruses, may protect against COVID-19 infection." Dan Tri newspaper quoted Dr Rhia Kundu, the Royal National Heart & Lung Institute (the study's lead author).
Scientists conducted the study on 52 people exposed to SARS-CoV-2, because they lived with COVID-19 patients (confirmed by PCR testing) and retested at 4 and 7 time. days later, to determine if they are infected. Study participants may also have been exposed to viruses of the corona family, such as the virus that causes the common cold.
T cells play a protective role against SARS-CoV-2 infection
Research shows that when the SARS-CoV-2 virus invades, in some people it can activate T cells that help the body remember previous illnesses, thereby eliminating the virus before the virus causes symptoms. . This may explain negative test results in some people despite their exposure to the pathogen. These T cells target the internal proteins of the SARS-CoV-2 virus, rather than the spike protein on the surface of the virus, to protect against infection.
"Our study provides the clearest evidence to date that T cells that fight the common cold coronavirus play a protective role against SARS-CoV-2 infection," said Prof. Ajit Lalvani, a member of the research team shared.
Humans and viruses are related in different ways depending on different factors. Whether a person becomes infected after coming into contact with someone with COVID-19 in their household depends directly on the amount of virus shed by the COVID-19 positive person, the conditions in that space, the immune system. epidemic and immunization status of the exposed person.
Some people inhale a small viral load from an infected person, but also someone inhale a large viral load. In other words, each person may have inhaled a different amount of the virus. In addition, everyone reacts differently to the virus based on their underlying medical condition, immune system, and other factors.
The Centers for Disease Control and Prevention (CDC) recommends that people get tested if they have been in contact with or may have been in contact with someone with COVID-19, or if they have symptoms of COVID-19.