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Fewer than 10% in the US have antibodies to the novel coronavirus – CNN

(CNN)A new nationwide study of the blood of more than 28,000 dialysis patients may help answer one of the big questions surrounding the pandemic: how many people have antibodies to SARS-CoV-2, the novel coronavirus?

The answer could tell us a lot about how many people in the United States have been exposed to the virus and how much community spread there has been. Plus, the testing strategy used in the study points to a relatively easy way to track Covid-19 disease activity over the long-term, especially among vulnerable populations.
The short answer to how many people had antibodies, as of July, is approximately 9.3% — although numbers ranged from an average of 3.5% in the West to an average of 27% in the Northeast.
“This research clearly confirms that despite high rates of COVID-19 in the United States, the number of people with antibodies is still low and we haven’t come close to achieving herd immunity. Until an effective vaccine is approved, we need to make sure our more vulnerable populations are reached with prevention measures,” study author Dr. Julie Parsonnet, a professor of medicine at Stanford University, said in a statement.
For the study, which was published Friday in The Lancet, researchers led by Stanford University’s Dr. Shuchi Anand, analyzed samples of plasma — a component of blood — from more than 28,500 patients receiving dialysis in July at approximately 1,300 facilities in 46 states run by one lab.
The overall percent of people who were positive for antibodies among those sampled was 8%. Because dialysis patients aren’t representative of the US population, the researchers standardized the results with respect to age, sex, race and ethnicity and region, to get an estimate of 9.3% seropositivity for the US adult population.
They found that there was a wide variation by state, with seven states having 0% seropositivity to New York, an early pandemic hotspot, topping the list with 33%.
The researchers were also able to see who was more likely to have antibodies. They found that, compared to the White population, residents of predominantly Black and Hispanic neighborhoods were two to three times more likely to be seropositive, people living in poorer areas were two times more likely and those living in the most densely populated areas were ten times more likely.
They also compared rates from their study with case counts from Johns Hopkins University. From that, they were able to estimate that only 9.2% of seropositive patients were actually diagnosed with Covid-19 using standard testing methods.
Why dialysis patients? For starters, “Patients receiving dialysis in the USA undergo routine monthly laboratory studies,” the researchers wrote, so there was no need for “considerable infrastructure and expense” to gather samples, nor were there other pandemic-related challenges.
Additionally, the risk factors for becoming infected with the coronavirus and for developing severe disease — including advanced age, non-white race, poverty, and diabetes — “are the rule rather than the exception in the US dialysis population.”
For those reasons, the researchers said that dialysis patients might be considered “an ideal sentinel population” in which to study the evolution of the pandemic.
But, as the authors of an accompanying commentary point out, questions still remain about how long the antibodies last and how protective they are. Still, studies like this, especially if it can be repeated on an ongoing basis, can help find answers.
“Anand and colleagues deserve credit for pioneering a scalable sampling strategy that offers a blueprint for standardised national serosurveillance in the USA and other countries with a large haemodialysing population,” wrote professors Barnaby Flower and Christina Atchison from Imperial College London. They were not involved in the study.
The study authors indicated the same. “A surveillance strategy relying on monthly testing of remainder plasma of patients receiving dialysis can produce unbiased estimates of SARS-CoV-2 spread inclusive of hard-to-reach, disadvantaged populations in the USA. Such surveillance can inform disease trends, resource allocation, and effectiveness of community interventions during the COVID-19 pandemic,” they wrote.

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Coronavirus antibodies fade fast, but protection may last longer – The Times of Israel

AP — New research suggests that antibodies the immune system makes to fight the new coronavirus may only last a few months in people with mild illness, but that doesn’t mean protection also is gone or that it won’t be possible to develop an effective vaccine.

“Infection with this coronavirus does not necessarily generate lifetime immunity,” but antibodies are only part of the story, said Dr. Buddy Creech, an infectious disease specialist at Vanderbilt University. He had no role in the work, published Tuesday in the New England Journal of Medicine.

The immune system remembers how to make fresh antibodies if needed and other parts of it also can mount an attack, he said.

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Antibodies are proteins that white blood cells called B cells make to bind to the virus and help eliminate it. The earliest ones are fairly crude but as infection goes on, the immune system becomes trained to focus its attack and to make more precise antibodies.

Dr. Otto Yang and others at the University of California, Los Angeles, measured these more precise antibodies in 30 patients diagnosed with COVID-19 and four housemates presumed to have the disease. Their average age was 43 and most had mild symptoms.

Researchers found that the antibodies had a half-life of 36 days, which means that half of them would be gone after that much time. It dovetails with a previous report from China also suggesting antibodies quickly fade.

The results “call for caution regarding antibody-based ‘immunity passports,’ herd immunity, and perhaps vaccine durability,” the California authors write.

Paramedic Jess Baddams (right) takes a blood sample from Tony Oliver, a front line ambulance worker, during a coronavirus antibody testing program at the Hollymore Ambulance Hub, in Birmingham, England, on June 5, 2020. (Simon Dawson/Pool via AP)

That’s true, Creech said, but other parts of the immune system also help confer protection. Besides churning out antibodies, B cells develop a memory so they know how to do that again if needed.

“They would get called into action very quickly when there’s a new exposure to the virus. It’s as if they lie dormant, just waiting,” he said.

Other white blood cells called T cells also are better able to attack the virus the next time they see it, Creech said.

Although circulating antibodies may not last long, what we need to know is if and how people remake antibodies if exposed to the coronavirus again and if they protect against another infection, Alison Criss, an immunologist at the University of Virginia, wrote in an email. “We also need to know if there is a protective T cell response” that reappears.

Vaccines, which provoke the immune system to make antibodies, might give longer-lasting protection than natural infection because they use purified versions of what stimulates that response, she noted.

Creech agreed.

“This shouldn’t dissuade us from pursuing a vaccine,” he said. “Antibodies are only a part of the story.”

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Coronavirus antibodies may last only two to three months after infection, study suggests – CNBC

A medical worker organizes antibody tests on April 29, 2020 in White Plains, NY.

Pablo Monsalve | VIEW press | Getty Images

Coronavirus antibodies may last only two to three months after a person becomes infected with Covid-19, according to a new study published Thursday in Nature Medicine.

Researchers examined 37 asymptomatic people, those who never developed symptoms, in the Wanzhou District of China. They compared their antibody response to that of 37 people with symptoms. The researchers found people without symptoms had a weaker antibody response than those with symptoms.

Within eight weeks, 81% of the asymptomatic people saw a reduction in neutralizing antibodies, compared with 62% of symptomatic patients. Additionally, antibodies fell to undetectable levels in 40% of asymptomatic people, compared with 12.9% of symptomatic people, according to the study’s findings.

Though the study is small, the researchers noted the findings may spur some world leaders to rethink issuing so-called “immunity passports.” Some countries have considered issuing passports or risk-free certificates to people who have antibodies against Covid-19, enabling them to travel or return to work assuming that they are protected against reinfection.

Scientists say they are still learning about key aspects of the virus, including how immune systems respond once a person is exposed. The answers, they say, may have large implications for vaccine development, including how quickly it can be deployed to the public.

One critical question among scientists is whether antibodies produced in response to Covid-19 offer protection against getting infected again. Additionally, scientists are still unsure of how long immunity lasts if antibodies do provide protection.

In general, antibodies that help the body fight off infections are produced in response to invading foreign particles or antigens. Vaccines work by inducing the immune system to produce these molecules. Health officials have said there is not enough data to indicate that coronavirus antibodies ensure immunity against the virus.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said earlier this month that a vaccine may not provide long-term immunity if Covid-19 behaves like other coronaviruses.

“When you look at the history of coronaviruses, the common coronaviruses that cause the common cold, the reports in the literature are that the durability of immunity that’s protective ranges from three to six months to almost always less than a year,” he said during an interview on June 2 with JAMA Editor Howard Bauchner. “That’s not a lot of durability and protection.”

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