T-cell Immunity ‘May Last Longer Than Antibodies’



These are the UK coronavirus stories you need to know about today.

T-cell Immunity ‘May Last Longer Than Antibodies’

UK preprint research gives evidence that T-cell immunity to SARS-CoV-2 may last longer than antibody immunity.

The research is from the UK Coronavirus Immunology Consortium (UK-CIC) and Public Health England.

It assessed cellular immune response at 6 months following primary infection in 100 healthy adults with asymptomatic or mild-to-moderate COVID-19.

Study author, Dr Shamez Ladhani, consultant epidemiologist at Public Health England, said: “Cellular immunity is a complex but potentially very significant piece of the COVID-19 puzzle, and it’s important that more research be done in this area. However, early results show that T-cell responses may outlast the initial antibody response, which could have a significant impact on COVID vaccine development and immunity research.”

Professor Paul Moss, UK Coronavirus Immunology Consortium lead from University of Birmingham, said: “To our knowledge, our study is the first in the world to show robust cellular immunity remains at 6 months after infection in individuals who experienced either mild/moderate or asymptomatic COVID-19. Interestingly, we found that cellular immunity is stronger at this time point in those people who had symptomatic infection compared with asymptomatic cases. We now need more research to find out if symptomatic individuals are better protected against reinfection in the future.”

Commenting via the Science Media Centre, Professor Charles Bangham, chair of immunology, Imperial College London, said: “These results provide reassurance that, although the titre of antibody to SARS-CoV-2 can fall below detectable levels within a few months of infection, a degree of immunity to the virus may be maintained.  However, the critical question remains: do these persistent T-cells provide efficient protection against re-infection?  It will also be important to follow the antibody and T-cell immunity in people who develop the syndrome of long COVID – the persistent and sometimes debilitating condition that follows acute SARS-CoV-2 infection in a still uncertain proportion of people.  Finally, the data in this paper reinforce the need for care in interpreting the results of serological (antibody) tests: it is still unclear how well either the antibody titre or the T-cell frequency correlate with actual protection against reinfection.”

2 Weeks to See Benefit of England’s Second Lockdown

NHS England’s Medical Director, Professor Stephen Powis, has cautioned that it’ll take until half way through England’s 4 week national lockdown to see improvements in infections. “It takes around a fortnight for today’s infections in the community to result in hospital COVID admissions – so what happens over the next 2 weeks is partly baked in. But the measures announced today [Oct 31] will help reduce the number of admissions beyond that,” he said in a statement.

“Daily hospital COVID admissions are now higher than on 23 March when the Prime Minister announced the first national lockdown.

“NHS doctors and nurses in many areas of England – including Liverpool, Lancashire, and Nottinghamshire – are now treating more COVID-19 patients than at the peak of the first wave.”

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Analysis: What Do Waning COVID-19 Antibodies Tell Us About Immunity and Vaccines? | Top News

LONDON (Reuters) – Growing evidence that COVID-19 antibody levels can wane swiftly after someone is infected is not necessarily bad news for immunity, experts said on Thursday, and does not mean protection offered by coronavirus vaccines will be weak or short-lived.

Specialists in immunology and viruses warned against reading too much into studies of antibody levels in the blood of people previously infected with COVID-19, cautioning that antibody readings do not translate directly into levels of protective immunity.

“The concentration of antibodies in your blood does not equal immunity,” said Eleanor Riley, a professor of immunology and infectious disease at Britain’s University of Edinburgh.

She and other experts said reports earlier this week which suggested immunity to COVID-19 might decline in line with falling blood antibody levels failed to account for the many complexities in how the body builds immunity to infections.

“Immunity is not something we can just wrap up in measuring an antibody or T-cell response,” she told Reuters. “Immunity is about the system working together so that next time you come across the infection, you either won’t get it at all or won’t get seriously ill from it. That’s protective immunity.”

While antibodies induced by natural COVID-19 infection may start to decline in few months, as a study by researchers at Imperial College found on Tuesday, the many potential COVID-19 vaccines in development are designed to induce more durable immunity by invoking strong so-called immune memory.

IMMUNE MEMORY IS MORE IMPORTANT

“Antibody responses are usually short-lived because once they have done their job you don’t need them,” said Jonathan Stoye, head of virology at Britain’s Francis Crick Institute.

“But that doesn’t mean that immunity, either induced by infection or by vaccination, is necessarily short-lived: Memory cells can respond to and combat a new infection.”

Since SARS-CoV-2, the virus that causes COVID-19, is a new human virus, scientists don’t yet know what levels of immunity will turn out to be protective. But many of the vaccine makers are touting both the antibody and T-cell responses, which are increasingly seen as important to lasting immunity.

“The immune system is very complicated. We know antibodies are important, but they’re not the whole story,” said Lawrence Young, a professor of molecular oncology at Britain’s Warwick University. “The important thing here is immune memory.”

Key to the process of immunity are memory cells known as T- and B-lymphocytes. Having made antibodies to a certain virus in an initial infection, the body uses these cells to remember that pathogen, “so when you are next exposed to the virus, the antibody response kicks in much sooner”, Young said.

With vaccines, a key feature is that scientists developing them can select as targets the most important bits of the pathogen – in COVID-19’s case these include the so-called “spike protein” on the surface of SARS-CoV-2 virus – to get the strongest and most lasting memory responses from T and B lymphocytes.

Some vaccines also contain stimulators or boosters, known as adjuvants, which can supercharge the

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U.K study finds sharp drop in COVID-19 antibodies just months after infection

One of the vexing things about coronaviruses like the common cold is that the immune response they induce is often short-lived. You catch a cold, recover and then catch it again six months later.

New research published Tuesday indicates fading immunity might also occur with the much more serious coronavirus, SARS CoV-2. Imperial College London scientists found that in a random sample of 365,000 adults in the United Kingdom, the presence of COVID-19 antibodies declined in all age groups by 26% from June to September.

The subjects in the REACT2 study, which has not been peer-reviewed, were given finger-prick tests in three rounds over the summer. After the first round, which ended in July, about 60 of 1,000 people in the sample, or 6%, had positive antibodies. By the end of September, that number had fallen to 44 per 1,000 (4.4%).

Age appeared to affect antibody duration. Younger people had higher levels than those over 65, and their antibodies lasted longer.


A faster decline in antibodies was observed in asymptomatic or mildly symptomatic cases than in those with full-blown symptoms, said Professor Wendy Barclay, head of the college’s infectious disease department, in a video call with journalists. Health care workers showed no change in antibody levels, possibly due to continuous on-the-job exposure to the virus.

“On the balance of evidence, I would say, with what we know for other coronaviruses, it would look as if immunity declines away at the same rate as antibodies decline away, and that this is an indication of waning immunity at the population level,” Barclay added.

“We don’t yet know what level of antibody is needed in a person’s blood to prevent reinfection,” she added.

Just a handful of cases of people getting COVID-19 twice have been confirmed. But immunity from the first wave of infections in March and April may only now be starting to dissipate, raising the prospect of more repeat cases, according to epidemiologists.

The findings suggest that those expecting increased infections to result in so-called herd immunity over time could be disappointed.

Herd immunity occurs when enough of a population is immune to a disease, making it unlikely to spread and protecting the rest of the community.

If no vaccine is developed, the portion of the population that would have to recover from COVID-19 in order to achieve herd immunity is estimated at about 70%, or more than 200 million people in the United States, according to the Mayo Clinic.

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Asymptomatic virus sufferers lose antibodies sooner: study

Asymptomatic coronavirus sufferers appear to lose detectable antibodies sooner than people who have exhibited Covid-19 symptoms, according to one of the biggest studies of its kind in Britain published on Tuesday.

The findings by Imperial College London and market research firm Ipsos Mori also suggest the loss of antibodies was slower in 18–24 year-olds compared to those aged 75 and over.

Overall, samples from hundreds of thousands of people across England between mid-June and late September showed the prevalence of virus antibodies fell by more than a quarter.

The research, commissioned by the British government and published Tuesday by Imperial, indicates people’s immune response to Covid-19 reduces over time following infection.

James Bethell, a junior health minister, called it “a critical piece of research, helping us to understand the nature of Covid-19 antibodies over time”.

But scientists involved cautioned that a great deal remains unknown about people’s long-term antibody response to the virus.

“It remains unclear what level of immunity antibodies provide, or for how long this immunity lasts,” said Paul Elliott, of Imperial’s School of Public Health. 

The study involved 365,000 randomly-selected adults administering at home three rounds of finger prick tests for coronavirus antibodies between June 20 and September 28.  

The results showed the number of people with antibodies fell by 26.5 percent over the approximate three-month period.

Scaled up to a nationwide level, it meant the proportion of the English population with antibodies dropped from 6.0 percent to 4.4 percent, according to the study.

The decline coincided with the prevalence of the virus falling dramatically across England — and the rest of Britain — following a months-long national shutdown which was eased over the summer.

However, the research found the number of health care workers testing positive for antibodies did not change over time, potentially reflecting repeated, or higher initial, exposure to the virus. 

“This very large study has shown that the proportion of people with detectable antibodies is falling over time,” said Helen Ward, one of the lead authors.

“We don’t yet know whether this will leave these people at risk of reinfection with the virus that causes Covid-19, but it is essential that everyone continues to follow guidance to reduce the risk to themselves and others.”

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Coronavirus antibodies estimated in less than 5% of French population: study

A nationwide study in France estimated that less than 5% of the population had coronavirus antibodies by mid-May.

The findings were posted ahead of peer review on Wednesday in medRxiv. Researchers from Public Health France, Department of Infectious Diseases, among others, said the study captures mild and asymptomatic cases that typically go unreported.

A nationwide study in France estimated that less than 5% of the population had coronavirus antibodies by mid-May.<br>
(iStock)

A nationwide study in France estimated that less than 5% of the population had coronavirus antibodies by mid-May.<br>
(iStock)

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Study authors estimated that, throughout the first wave of the epidemic, nationwide prevalence of antibodies climbed from 0.41% in March to nearly 5% by May, which translates to 3,292,000 infections, according to the study.

Also, about 70% of those with antibodies had detectable neutralizing antibodies, which varied across ages and regions, authors wrote.

Blood samples were analyzed from 11,021 people and then extrapolated to the nationwide population.

CORONAVIRUS ANTIBODIES PRESENT IN LESS THAN 10% OF AMERICANS, STUDY FINDS

“Seroprevalence estimates confirm that the nationwide lockdown substantially curbed transmission and that the vast majority of the French population remains susceptible to SARS-CoV-2 [the virus causing COVID-19 disease],” study authors wrote.

Antibody prevalence was highest in the area including Paris, where researchers noted the spread of infections happened earlier and more intensely.

“Our results are within the same order of magnitude as studies carried out at comparable epidemic stages in Europe,” the authors also wrote.

The study also found low infections among schoolchildren and suggested that the age group has restricted susceptibility and/or transmissibility.

“Our results provide a critical understanding of the progression of the first epidemic wave and provide a framework to inform the ongoing public health response as viral transmission is picking up again in France and globally,” they concluded. “Serological surveillance based on residual sera will continue to be used to provide timely seroprevalence estimates as the epidemic evolves and through the 2020-2021 winter season to monitor the progression of population-level immunity and guide public health response.”

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Research Antibodies and Reagents Market worth $14.1 Billion by 2025

CHICAGO, Oct. 20, 2020 /PRNewswire/ — According to the new market research report Research Antibodies and Reagents Market by Product (Antibodies (Type, Form, Source, Research Area), Reagents), Technology (Western blotting, Flow Cytometry), Application (Proteomics, Drug Development), End User – COVID-19 Impact – Global Forecast to 2025“, published by MarketsandMarkets™, the global market size is projected to reach USD 14.1 billion by 2025 from USD 10.1 billion in 2020, at a CAGR of 6.7% during the forecast period.

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The growth is due to evolution of market owing to factors such as growth in proteomics and genomics research, rising demand for high-quality antibodies for research reproducibility, and increasing R&D activity and expenditure in the life sciences industry. Fueled by the growing demand for personalized medicine and structure-based drug design, the global market is expected to witness significant growth in the coming years.

Browse in-depth TOC on “Research Antibodies and Reagents Market”

220 – Tables
45 – Figures
278 – Pages

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The COVID-19 outbreak has boosted research activity due to efforts to understand the dynamics of the infection. We estimate that the major share of research antibody and reagent manufacturing, along with personalized medicine, will grow at a stable pace in the next five years. Due to the increase in research activity, both the availability of funding for research and the demand & manufacturing of reagents and antibodies are expected to grow. As companies after pandemic have scaled up their operations for testing and tracking the infection of COVID-19. This has given a chance for growth in profits for companies operating in the NGS and PCR markets. The growth in revenue is 5–7%, as COVID-19 testing has increased with the use of the latest technology of genetic and molecular testing. The shift in demand for research for COVID-19, neurobiology, and oncology has created a huge scope for testing solutions, such as western blotting, flow cytometry, ELISA, and drugs for researchers and laboratories.

The antibodies segment is expected to grow at the highest CAGR during the forecast period

Based on product, the research antibodies market is segmented into reagents and antibodies. The antibodies segment is expected to grow at highest CAGR in forecast period. This is due to the research-use antibodies offer high specificity and selectivity and are used ubiquitously in biochemical and medical research for protein-target identification, regulatory characterization, and discovery.

The primary antibodies segment is accounts for the largest share of the research reagents market

Based type, the research reagents market is segmented into primary antibodies and secondary antibodies. The primary antibodies segment held the largest share of the global research antibodies market in 2019. This segment is witnessing a strong growth due to the use of these antibodies in numerous types of assay formats. Their accuracy in biomarker detection and their high specificity and sensitivity are also driving their adoption

The media & sera reagent is expected to account for the largest share of the market, by type, in 2019

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