Survivors of COVID-19 may have protective antibodies for 4 months

A new study by researchers at Harvard Medical School and Massachusetts General Hospital (MGH) aims to determine the duration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity in COVID-19 survivors. is. Researchers have found that people who survive the severe COVID-19 disease have a long-term immune response to SARS-CoV-2.

Studies published in the journal Scientific immunology, It emphasizes the body’s immune response to COVID-19. It also provides the hope that people infected with the SARS-CoV-2 virus will develop permanent protection against reinfection.

the study

In this study, researchers focused on the receptor-binding domain (RBD) of the viral “spiked” protein, which binds to cells via the angiotensin-converting enzyme 2 (ACE2) receptor and causes infection.

When the immune system senses that a pathogen like SARS-CoV-2 has invaded the body, it produces a protein called an antibody. The body develops an immune response, but it is unknown how long these antibody responses will last.

To reach the findings, the team collected blood samples from 343 patients infected with SARS-CoV-2. Most of them were severe cases. These blood samples were taken within 4 months of the onset of symptoms.

Researchers isolated plasma and applied it to RBD-coated laboratory plates. Spike protein.. They analyzed how different types of antibodies in plasma attach to RBD. The results of the study were compared with blood samples collected from 1,548 people prior to the pandemic.

Study results show that immunoglobulin G (IgG) levels remain elevated in COVID-19 patients for 4 months and are associated with the presence of protection. Neutralizing antibody, Showed a slight decrease in activity over time.

Therefore, the researchers concluded that people are very likely to be protected for four months, indicating that there is a major antibody response to COVID-19.

More accurate IgG level measurement

Measurements of IgG levels were also found to be more accurate in detecting people who had symptoms for at least 14 days.

“These data show that antibodies targeting RBD are excellent markers of previous and recent infections, different isotype measurements help distinguish between recent and older infections, and these IgG responses are post-infection. It lasts for the first few months, suggesting that it is highly correlated with neutralizing antibodies, “the researchers wrote in the paper.

They identified some of the SARS-CoV-2 standard tests, the polymerase chain reaction (PCR) nasal swab, becoming less sensitive over time, adding antibody tests to patients who had symptoms for at least 8 days. I added that it helps to do. Positive cases that can be overlooked.

The team also added that people infected with the coronavirus responded to immunoglobulin A (IgA) and immunoglobulin M (IgM) and dropped to low levels about two and a half months after infection. If a patient is tested positive for these antibodies, they may have been infected with COVID-19 in the last two months.

Knowing the duration of the body’s immune response to SARS-CoV-2 by testing IgA and IgM levels can help provide more accurate data on the spread of infection.

“There are many infectious diseases in the community that are not detected by PCR tests during acute infections, especially in areas where access to the tests is restricted,” said Jason Harris, a pediatric infectious disease specialist at MGH. Explained. ..

“It is essential to use antibody testing to track the spread of COVID-19 and to know how long the antibody response will last before identifying the” hotspot “of the disease,” he added.

Of the more than 37.39 million cases of COVID-19 worldwide, more than 25.99 million have already recovered. Many vaccines are currently being tested to see if they can be used effectively and safely by the general public. A better understanding of the body’s antibody response to SARS-CoV-2 will also help scientists develop vaccines that can provide protection against the rampant virus.