When an outbreak of coronavirus on a trawler in Seattle infected more than 100 crew members in May, three fishermen were spared antibodies, according to a new study, and provided stimulating evidence about our immunity to infection.
© Simon Dawson / Bloomberg
Test tubes to use for blood samples sit on a table during an anti-antibody test program at the Hollymore Ambulance Hub in Birmingham, UK, on 5 June. (Simon Dawson / Bloomberg)
The study, which was published Friday and has not been peer-reviewed, offers hope that antibodies can provide protection against infection. But the investigation into the outbreak of the fishing boat has a catch.
While scientists say the study will help us understand how antibodies limit coronavirus infection, they warn that the presence of antibodies definitely does not guarantee immunity. Researchers are still trying to understand what immunity to the coronavirus looks like and despite the successful University of Washington, much remains to be seen.
Even as a stream of new immunology research is published about the new virus, mysteries remain unsolved about how people like the fishermen are able to stay safe from the grip of covid-19, the disease caused by the virus. The Washington Post received hundreds of questions from readers about immunity to the virus, of what it will take to achieve herd immunity about how virus mutations can affect a person’s immune response. We have posed several of these questions to researchers, and here is what we found out.
How does immunity against coronavirus work?
Immunologists say that immune responses of coronavirus patients usually follow with other viral diseases such as the flu.
To protect against viruses, the human body has an immune arsenal with multiple attacks that it uses. The first defense is T cells, specialized white blood cells that remember the virus, blood proteins that neutralize infection. However, the presence of antibodies does not mean that someone is unsafe for infection.
“It’s not black and white, whether you are immune or not immune,” Sarah Fortune, the president of immunology and infectious diseases at the TH Chan School of Public Health at Harvard University, told The Washington Post. “There are degrees of immunity.”
While antibodies may disappear in the weeks after infection, longer-lived B cells that produce antibodies continue to infect over time.
“Your immune response is generally tricked into going up when the danger is high, and then things can escalate when the danger is over,” Fortune said.
However, the presence of antibodies in the three fishermen on the American Dynasty ship that rocked the outbreak indicates that her body had built a defense against the coronavirus, possibly from a previous infection.
Those three were the only people with antibodies on board the ship out of 122 people scientists had collected blood samples from before sailing. After 18 days at sea, the virus had hovered 85 percent of the boat’s crew, but those three did not sit, hinting at immunity, researchers wrote.
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FOLLOWING
How long are the body’s defenses against the virus effective?
The Centers for Disease Control and Prevention accidentally reported last week that covid-19 patients had months of immunity when they shared the updated guidance advising people not to seek a test for three months after recovering from the coronavirus to have.
However, the agency clarified its advice, saying it was about how retesting could lead to false positions.
“Contrary to current media reports, this science does not imply that a person is immune to reinfection with SARS-CoV-2, the virus that causes covid-19, in the next 3 months of infection,” the CDC said in a statement. . “The latest data simply suggest that testing someone within 3 months after initial infection is not necessary unless that person exhibits the symptoms of covid-19 and the symptoms cannot be associated with another disease.”
The CDC advises people recovering from the coronavirus to still socialize and wear face masks as researchers learn how effective antibodies are in repelling infection.
Scientists discovered the body’s defenses against the coronavirus – antibodies, T cells and B cells – appear to be maintained for three months past when the infection has run its course, even among patients with mild cases, according to a separate study by the University of Washington published Saturday.
After research indicated that antibody counts of those who could heal in months, some speculated that immunity to the virus could be short-lived. But immune systems also produce fewer antibodies when they are not under viral attack, said immunologist and co-author Lauren Rodda.
Rodda and other researchers counted the B and T cells that produce antibodies and found that the numbers remained stable as they increased.
“It shows that the immune system is working as it should,” Rodda said.
While scientists are hoping to find out how these cells could protect against coronavirus reinfection in humans, recent research by rhesus monkeys has shown that primary exposure to coronavirus offers protection against reinfection or serious illness.
“These studies that show that primary infection is actually protective, at least in monkeys, are starting to build this very promising story about people who have been immune for at least three months, probably longer, but we just don’t know yet,” Rodda said. .
Is herd immunity possible?
If there is hope that reinfection is unlikely, then that begs the question: How many cases will it take for the country to develop herd immunity?
There is no consensus on when the United States can achieve herd immunity – the point being that a large portion of the population is immune, making it harder for the virus to circulate much. Estimates for the coronavirus range from 40 to 80 percent.
But public health experts including Trevor Bedford, a scientist at the Fred Hutchinson Cancer Research Center in Seattle, caution that people should try to go social distance and wear masks to prevent the spread of the virus.
While the “substantial outbreaks in Arizona, Florida and Texas” provided great immunity, “the costs of this immunity have been substantial and continue to rise,” Bedford said. tweeted. “We need a vaccine to achieve population immunity in a way that does not kill people.”
Re-immunity can be caused by the advent of a vaccine, but some viruses that have vaccines, such as measles, can still infect humans.
“If you have infected large proportions of the population, it is very difficult for the virus to spread, but it may find niches where it can spread,” said Florian Krammer, an immunologist at the Icahn School. or Medicine at Mount Sinai in New York. Peal. “That it is highly unlikely that we will ever lose SARS-CoV-2.”
Like the flu, will people need to get a coronavirus vaccine every year?
When a vaccine becomes publicly available, researchers are still unsure how effective it will be to protect humans against coronavirus over time.
The flu vaccine is new every year. But the mutation process for flu is large, which means it replaces larger parts of its genes, compared to the coronavirus, Fortune said.
Since the new virus does not change at the same cadence as the flu, people may only need to be vaccinated once – or possibly get an immunization and booster shot.
Fortune compares the selection of faxes with dating perspectives: “No one is perfect, but you just choose the features you like best.”
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