The proportion of people with antibodies to coronavirus detectable in Britain has dropped by about 27 per cent over a three-month period this summer, researchers reported Monday, saying the virus’s immunity is short-lived.
But some experts said these concerns have been suppressed. It is common for the body to have low levels of antibodies after clearing the infection, but immune cells carry the memory of the virus and can strip fresh antibodies when needed.
“Some of these headlines are stupid,” said Scott Hansley, an immunologist at the University of Pennsylvania.
A decrease in antibody levels after the acute infection has resolved is a sign of a “normal healthy immune response,” said Dr. Said Hansley. “That doesn’t mean they don’t have antibodies. That doesn’t mean they don’t have security. “
Research has also raised some concerns about the vaccine’s ability to help populations reach herd immunity, at which point enough people are immune to coronavirus to thwart its spread.
It is too early to know how long immunity to the new coronavirus lasts, and whether people can be re-infected in a year for several months after the first round with the virus. However, experts said concerns about the vaccine are also uncontrollable.
“This vaccine does not require a copy of a natural infection or a mirror,” said Sherry Croti, a virologist at the La Jolla Institute for Immunology. “Certainly I would not be an alarmist about this data.”
The new results indicate the prevalence of coronavirus antibodies in a wide population but not in specific individuals. Some studies focusing on antibody levels in individuals have shown that after some initial decline, levels remain stable for at least four to seven months.
The British report is based on three rounds of antibody blood tests in randomly selected rand 350,000 people from June 20 to September 28. Participants tested themselves at home for antibodies using finger-prick aces, which did not give a yes-or-no result, like a pregnancy test.
Over a three-month period, the proportion of people with detectable antibodies in their blood dropped from one percent to 8.8 percent, the researchers said. The lowest decline was in people aged 18 to 24 and the largest in people over 75.
Dr. Ant, a virologist at Duke NUS Medical School in Singapore. “It’s not such a dramatic reduction.”
Antibodies also represent only one arm of the immune response, however, which one can measure very easily. There are at least three other branches of the immune system that can prevent disease, so antibody levels do not present a complete picture.
“It’s not a complete immune response,” said an epidemiologist at Imperial College London. Paul Elliott, chairman of the project, said.
When a pathogen is found in the body, it quickly produces antibodies that recognize the invader. Once the acute infection has resolved, the level is reduced – as it is necessary for a completely practical reason.
Dr. Our. “Our lymphatic system, where there are immune cells, has only a limited amount,” Hansley said.
Depending on the test used, there is still a small amount of antibodies circulating in the blood, which is not enough for a positive signal. The test used in the study has a sensitivity of .84. of percent, which is about 99 percent of that compared to lab-based tests. This means it can miss anyone who has low levels of antibodies.
For example, people with mild to moderate symptoms may produce fewer antibodies than people with serious illness. Most people with positive results were sick at the peak of an outbreak in Britain in March or April, but about 30 per cent do not recall having any Covid-19 symptoms. Even a small decrease in the amount of antibodies can leave their levels below the test threshold.
Confused by the terms about coronavirus testing? Let’s help:
- Antibody: A protein produced by the immune system that can accurately identify and attach certain types of viruses, bacteria, or other invaders.
- Antibody Test / Serology Test: A test that detects specific antibodies to coronavirus. Antibodies begin to appear in the blood about a week after the coronavirus infects the body. Since antibodies take so long to develop, antibody testing cannot make a reliable diagnosis of an ongoing infection. But it can identify people who have been exposed to coronavirus in the past.
- Antigen testing: This test detects bits of coronavirus proteins known as antigens. Antigen tests are faster, taking less than five minutes, but are less accurate than tests to detect genetic material from a virus.
- Corona virus: Any virus that belongs to the orthocoronavirus family of viruses. The covid-virus that causes covid-19 is known as SARS-cov-2.
- Covid 19: The disease is caused by a new coronavirus. The name coronavirus disease is short for 2019.
- Isolation and quarantine: Isolation is the isolation of people who know that people who are not sick are sick with an infectious disease. Quarantine refers to limiting the movement of people who have been exposed to the virus.
- Nasopharyngeal swab: A long, flexible rod, tipped with a soft swab, is inserted into the nose serted to obtain a sample from where the nasal cavity meets the throat. Samples of coronavirus tests can also be collected with swabs that do not go deep into the nose – called nasal swabs – or oral or throat swabs.
- Polymerase chain reaction (PCR): Scientists use PCR to create millions of copies of genetic material in a sample. Tests using PCR enable researchers to detect coronavirus even though it is rare.
- Viral load: The amount of virus in a person’s body. In people infected with coronavirus, if symptoms do not appear, the viral load may increase before they begin to show symptoms.
“We are saying that the antibody response has fallen below the threshold,” Dr. Elliott said. “Not surprising for anyone working in the field.”
Data from monkeys suggest that even low levels of antibodies can prevent serious illness from the virus, if not re-infected. Even if the level of the spread antibody does not diagnose, the body retains the pathogen’s memory. If it crosses the pathways with the virus again, balloon-like cells living in the bone marrow can produce large amounts of antibodies in hours.
A very small number of people cannot make any antibodies. But those people may have immune cells called T cells that can recognize and destroy the virus. Most people who develop coronavirus develop persistent cellular reactions, according to several recent studies.
T cells are unlikely to prevent infection, but they can at least prevent a serious illness by rubbing off the attack, said Dr. Said Croty. Given all that, he said, interpreting low levels of antibodies means that the immune system disappears, or that the coronavirus vaccine won’t be effective is “wrong.”
For example, the human papillomavirus “has a terrible immune response and lotus antibodies,” he said. “But not even a single immunization vaccine releases strange antibodies. People who are 99 percent protective for more than 10 years are just a full night and day difference.”
He added that vaccines can also be designed to respond more than natural infections.
Despite criticism of its many interpretations, experts say the results of the new study are an interesting glimpse into the prevalence of antibodies at the population level.
The same research team is also investigating millions of people for the presence of the virus. Dr Elliott said the study provides policymakers with a “truly powerful tool” for measuring the country’s epidemic size.