Antibodies declined for months after a mild COVID-19

Wednesday, July 22, 2020 (HealthDay News)-The hopes of strong and long-term antibody protection after COVID-19 seizures are weakened by a new study discovering that protection may last for only a few months It was.

Nonetheless, experts say this finding does not undermine the promise of vaccines, as the body’s immune system has multiple ways to protect against viruses that have already been encountered.

“Infection with this coronavirus does not always create lifelong immunity,” said Dr. Buddy Kleich, an infectious disease specialist at Vanderbilt University in Nashville. AP communication..

But antibodies were only part of the immune system’s gear, added Creech, who wasn’t part of the new study.

The study was published on 21 July New England Medical Journal.. Researchers led by Dr. Otto Yang at the University of California, Los Angeles have sought to determine the “half-life” of antibodies produced by contact with the new SARS-CoV-2 virus. Half-life is the time it takes for half of the antibody to disappear.

Yang’s group took blood samples from 34 people who all recovered from a mild case of COVID-19. Twenty were women and 14 were men, on average 43 years old.

Based on blood tests collected by 119 days after the onset of symptoms, the researchers said the half-life of antibodies associated with SARS-CoV-2 infection was only 73 days, or about 2.5 months. At that rate, the antibody disappears completely in about a year.

That is “antibody loss” [rate] This was faster than that reported for SARS-CoV-1,” said the coronavirus that caused the 2003 SARS outbreak.

“Our findings raise concerns about humorality [found in body fluids] “The immunity to SARS-CoV-2 may not last long in the milder people who make up the majority of people with COVID-19,” they said.

“Similar to common coronaviruses that cause colds, the new coronavirus does not seem to provide durable antibody-based immunity for long periods of time,” said a senior researcher at the Johns Hopkins Health Security Center in Baltimore. Says Dr. Amesh Adalya.

However, this does not mean that immunity is always lost because the human immune system has other strategies.

“T-cell immunity is also an important factor to consider, so we don’t yet know if these individuals can reinfect and, if so, what their clinical course will be,” he said. Adalja said. Investigation.

T cells are a distinct component of what is called the adaptive immune system. They help fight infection in many ways, including killing infected cells directly.

Kurecht agreed that the relatively short half-life of antibodies to SARS-CoV-2 does not mean that people lose their ability to fight recurrent infections.

He explained to AP The antibody is a protein produced by immune system B cells to help recognize and destroy virus-infected cells. The first time a new virus is encountered, more generalized forms of the antibody will be produced immediately, but the specificity for the virus will become more accurate over time.

B cells also develop a kind of memory on how the virus produces these correct antibodies when the virus reappears in the body.

“When they’re newly exposed to the virus, they’ll be put into action very quickly. It looks as if they’re sleeping, they’re just waiting,” Kurech said. T cells are also waiting to be able to launch a separate fight against infected cells, he said.

And what about your hopes for a vaccine?

Efforts to find an effective vaccine are still valid, said Kleich, because the vaccine’s highly targeted approach to the virus actually exceeds that of the natural immune system.

“This should not discourage us from pursuing a vaccine,” Kleich said. “Antibody is just part of the story.”

For more information

For more information on how the immune system works, US Medical Library..