COVID-19 antibodies last at least three months; so do symptoms for many

(Reuters) – The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

FILE PHOTO: Convalescent plasma samples in vials are seen before being tested for COVID-19 antibodies at the Bloodworks Northwest Laboratory during the coronavirus disease (COVID-19) outbreak in Renton, Washington, U.S. September 9, 2020. REUTERS/Lindsey Wasson

COVID-19 antibodies last at least three months

People infected with COVID-19 develop antibodies targeting the new coronavirus that last for at least three months, according to two reports published on Thursday in Science Immunology. The two studies, together involving nearly 750 patients, both point to immunoglobulin G (IgG) antibodies, which start showing up well after an infection begins, as the longest-lasting. Researchers found IgG antibodies with two targets – a spike protein on the virus that helps it infect cells, and a part of the spike called the receptor binding domain (RBD) – lasted more than 100 days. While the protective effect of COVID-19 antibodies is not completely clear, Jen Gommerman of the University of Toronto, coauthor of the study, said her team also found levels of so-called neutralizing antibodies, which inactivate the virus, “appeared to be very stable.” The other study, from Harvard Medical School, reported similar findings. This means that a properly designed vaccine “should elicit a durable antibody response that has the potential to neutralize the virus,” Gommerman said. Her group also found that antibodies in saliva correlated with antibodies in blood, but at this point the saliva tests are not sensitive enough to replace blood tests. (;

COVID-19 symptoms linger for months for many

Three months after becoming ill, many COVID-19 patients still have symptoms, two studies confirm, and the more severe the initial infections, the higher the odds of persistent problems. In Spain, doctors checked back with 108 patients, including 44 who had been severely ill. At 12 weeks after diagnosis, 76% still reported after-effects, with 40% reporting three or more coronavirus-related health issues, doctors said in a paper posted on Thursday on medRxiv ahead of peer review. The most common complaints were shortness of breath, physical weakness, cough, chest pain, palpitations, and psychological and cognitive disorders. In a similar study of 233 U.S. COVID-19 patients – eight of whom had been severely ill – one in four still had symptoms 90 days after first feeling ill. Rates were higher for patients who had been sicker: 59.4% at 30 days and 40.6% at 90 days. “But even for very mild and initially asymptomatic cases, 14.3% have complications persist for 30 days or longer,” the authors reported on Sunday on medRxiv. In the U.S. study, the most common persistent symptoms were impaired smell and taste, difficulty concentrating, shortness of breath, memory loss, confusion, headache, heart palpitations, chest pain, pain with deep breaths, dizziness, and rapid heartbeat. (;

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What are polyclonal antibodies? | Fox News

On Friday, the White House revealed that President Trump was given a dose of an antibody cocktail following his coronavirus diagnosis.


According to a statement from White House press secretary Kayleigh McEnany, Trump received an 8-gram dose of the polyclonal antibody cocktail, REGN-COV2, from pharmaceutical company Regeneron, as a “precautionary measure.”

President Trump tested positive for the coronavirus on Friday. (iStock)

President Trump tested positive for the coronavirus on Friday. (iStock)


Polyclonal antibodies are made up of heterogeneous cells which “are usually produced by different B cell clones in the body,” according to Creative Diagnostics, a privately-owned American company specializing in the research and manufacturing of antibodies. Polyclonal antibodies can identify and attach to different epitomes, a specific piece of a single antigen.

They are produced in live beings, whereas monoclonal antibodies are produced using tissue-culture techniques, the biotechnology company reported.

To create the polyclonal antibodies, an immunogen is typically injected to elicit an immune response. An immunization is then injected to “produce higher titers of antibodies against the particular antigen.”

The experimental treatment uses an antibody made by the Regeneron, as well as with one isolated from people who have survived COVID-19. The intent is for the two antibodies to bind to the coronavirus’ protein, “limiting the ability of viruses to escape,” Reuters reported.

The treatment has shown effectiveness in decreasing the amount of virus in the body and severity of symptoms, Dr. Matt McCarthy, an infectious disease doctor, told FOX Business’s Stuart Varney.


“If I got brought in today to the Oval Office, first thing I’d say is, has anyone reached out to Regeneron?” McCarthy said. “Has anyone talked about an antibody cocktail for him? Three days ago, the company showed that they can reduce the amount of virus in the body and that they can decrease the duration of symptoms.”

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‘Fatigued’ Trump receiving experimental antibodies treatment

US President Donald Trump is receiving an experimental treatment of synthetic antibodies for Covid-19, his doctor said Friday, and is “fatigued but in good spirits.”

Trump received a single dose of Regeneron’s antibody cocktail, according to a letter issued by White House physician Sean Conley.

The treatment is undergoing clinical trials but hasn’t received any form of regulatory approval. 

“He’s being evaluated by a team of experts, and together we’ll be making recommendations to the President and First Lady in regards to next best steps,” Conley said.

Trump — who has repeatedly cast doubt on the seriousness of the pandemic — first announced in an overnight tweet that he and First Lady Melania Trump, 50, had tested positive and were going into quarantine.

Earlier this week, Regeneron announced results from one of its early-stage trials which showed its drug, which is infused intravenously, reduced viral load and recovery time in non-hospitalized Covid-19 patients.

“We have begun discussing our findings with regulatory authorities while continuing our ongoing trial,” said George Yancopoulos, the company’s president and chief scientific officer on Tuesday.

The US biotech firm is concurrently running late-stage trials for hospitalized Covid-19 patients and for the drug’s potential use as a prophylaxis. 

Antibodies are infection-fighting proteins made by the immune system that can bind to particular structures on the surfaces of pathogens and prevent them from invading cells.

Vaccines work by teaching the body to make its own antibodies, while scientists are also testing ready-made antibodies from the blood of recovered patients, called convalescent plasma.

But it is not possible to make convalescent plasma a mass treatment.

Researchers can also comb through the antibodies produced by recovered patients and select the most effective out of thousands, and then manufacture it at scale.

Regeneron’s experimental Covid-19 drug, called REGN-COV2, is a combination of two antibodies, referred to as a “cocktail.”

The idea is it will have a better chance at working if the virus mutates in order to evade the blocking action of a single antibody.

Last year, a triple-antibody cocktail developed by Regeneron was shown to be effective against the Ebola virus.


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Study: COVID-19 antibodies decline quickly in donated plasma

Antibodies against COVID-19 in people who’ve recovered from the disease begin to vanish about three months after they develop symptoms, researchers say.

This suggests that sooner is better for recovered COVID-19 patients to donate antibody-containing blood plasma for convalescent plasma treatment, according to the authors of a small study published Oct. 1 in the journal Blood.

“Based on our findings, antibodies against the new coronavirus are not eternal,” said study author Renée Bazin, director of innovation at Canada-based Héma-Quebec blood center.

Bazin’s team said their findings may prove important for creating vaccines and research into how many people have recovered from COVID-19.

In convalescent plasma treatment, plasma from recovered patients is given to newly ill patients in an attempt to boost their ability to fight the virus.

“While many clinical trials are underway to better understand whether convalescent plasma is clinically beneficial for treating COVID-19, a key question is at what time point is it most effective to collect donor plasma based on the presence of antibodies that help fight the virus,” Bazin said in a news release from the American Society of Hematology.

The study included 15 adults who recovered from COVID-19. Their symptoms ranged from mild to severe, but none were hospitalized.

Each person donated plasma between four and nine times. The first donation was 33 to 77 days after symptoms began, and the last donation was made between 66 and 114 days.

By about 88 days, all 15 donors had decreases in antibodies, and half of detectable antibodies dropped within 21 days after that, the investigators found.

“The antibodies disappear rapidly, so people recovering from COVID-19 who want to donate blood plasma should not wait too long once they become eligible to donate,” Bazin said.

Based on these findings, she said clinicians should check for presence of antibodies before giving donor plasma to a patient.

More information

The U.S. Centers for Disease Control and Prevention has more on COVID-19.

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