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Novel antibody reduces severity of COVID-19 infection: Study

Scientists have identified and tested an antibody that limits the severity of infections from a variety of coronaviruses, including those that cause COVID-19 as well as the SARS illness. The study, published in the journal Science Translational Medicine on Tuesday, isolated the antibody by analysing blood from a patient who had been infected with the SARS-CoV-1 virus, which caused the SARS outbreak, and from a current COVID-19 patient.

“This antibody has the potential to be a therapeutic for the current epidemic,” said study co-senior author Barton Haynes, director of Duke University Human Vaccine Institute (DHVI), US.

“It could also be available for future outbreaks, if or when other coronaviruses jump from their natural animal hosts to humans,” Haynes said.

The researchers identified over 1,700 antibodies, which the immune system produces to bind at specific sites on specific viruses to block the pathogen from infecting cells.

When viruses mutate, many binding cites are altered or eliminated, leaving antibodies ineffectual, they said.

However, the researchers noted that there are often sites on the virus that remain unchanged despite mutations.

They focused on antibodies that target these sites because of their potential to be highly effective across different lineages of a virus.

Of the 1,700 antibodies from the two inpiduals, the researchers found 50 antibodies that had the ability to bind to both the SARS-CoV-1 virus as well as SARS-CoV-2, which causes COVID-19.

Further analysis found that one of those cross-binding antibodies was able to bind to a multitude of animal coronaviruses in addition to the two human-infecting pathogens.

“This antibody binds to the coronavirus at a location that is conserved across numerous mutations and variations,” Haynes said.

“As a result, it can neutralise a wide range of coronaviruses,” he explained.

Researchers at the University of North Carolina at Chapel Hill (UNC), US, tested the antibody in mice to determine whether it could effectively block or minimise the infections.

They found that when given before the animals were infected, the antibody protected mice against developing SARS, COVID-19 and its variants such as Delta.

The researchers also found that the antibody provide protection from many animal coronaviruses that have the potential to cause human pandemics.

“The findings provide a template for the rational design of universal vaccine strategies that are variant-proof and provide broad protection from known and emerging coronaviruses,” said study co-senior author Ralph S Baric, a professor at UNC Gillings School of Global Public Health.

When given after infections, the antibody reduced severe lung symptoms compared to animals that were not treated with the antibody, according to the researchers.

“The therapeutic activity even after mice were infected suggests that this could be a treatment deployed in the current pandemic, but also stockpiled to prevent the spread of a future epidemic with a SARS-related virus,” said David Martinez, a post-doctoral researcher at UNC’s Gillings School.

“This antibody could be harnessed to prevent maybe SARS-CoV-3 or SARS-CoV-4,” Martinez added.

Covid-19: A cure still elusive, but science may find a way

Countries are emerging from lockdowns even as the fear of a second wave of Covid-19 continues with new spikes seen in China and South Korea. India, too, continues to see new cases and is one of the few countries to witness a rise after substantially relaxing lockdown restrictions. Scientists at drug and vaccine companies are making all efforts towards finding a cure for the pandemic. Divya Rajagopal reports on the developments through this week both in India and across the world:

Panacea Biotech ties up with Refana

New Delhi-based Panacea Biotech has formed a joint venture with Refana, a US-based early stage life sciences company, to develop a whole inactivated virus-based vaccine. The first phase of trials is expected to start in September. The vaccine is expected to be ready for administration within the next 18 months if the first-phase trials are found to be effective.

Bharat Serum to start trials on Sepsis drug

Mumbai-based Bharat Serum and Vaccines (BSVL) will start clinical trials in India on the effectiveness of the generic drug Ulinastatin, used for treating sepsis (septicemia), in addressing the acute respiratory distress syndrome (ARDS) common among Covid-19 patients. The company has got approvals from the drug regulator to conduct the third phase of the clinical study on Ulinastatin for patients having mild to moderate symptoms of ARDS. It is expected to conclude by September.

J&J advances vaccine trials
Drug maker J&J has advanced its Covid-19 vaccine trial from September to mid-July based on the strength of its pre-clinical data, according to Paul Stoffels, chief scientific officer at J&J. The company expects to deliver its recombinant vaccine Ad26. COV2-S through 2021 provided it is safe and effective.

AstraZeneca, Eli Lilly, Regeneron explore antibody drugs

Neutralising antibodies are the latest class of drugs being explored. Companies such as AstraZeneca, Eli Lilly and Regeneron have begun work in this field.

AstraZeneca

said it has licensed coronavirus-neutralising antibodies from Vanderbilt University, US, and plans to advance a pair of these monoclonal antibodies into clinical development as a potential combination therapy.

Presence of antibodies may not guarantee protection from COVID-19, say scientists

New Delhi: The presence of antibodies indicates previous exposure to the SARS-CoV-2 virus but may not always translate into protection against the disease, say scientists, citing imponderables such as what kind of antibodies, how many and how long they last.

As worries over India’s COVID-19 spike mount – the country added 90,062 cases on Monday to take its tally past the 42-lakh mark – scientists are grappling with the pivotal issue of antibodies and trying to understand how they impact on the progression of the disease.

But the jury is still out there with several studies and hypotheses but no consensus yet. The only thing that can be said with any degree of uncertainty is that antibodies is a sign that the person has already been infected with the novel coronavirus, the scientists said.

Immunologist Satyajit Rath said he would prefer to “wait and see” where the evidence goes.

Antibody presence in itself tells us nothing about disease progression in inpiduals, said the scientist from New Delhi’s National Institute of Immunology (NII).

There are neutralising antibodies (nAbs) and also ‘simple’ antibodies. While nAbs produced against the novel coronavirus can block its entry into the host cell, other antibodies are also generated against many parts of the virus, added Vineeta Bal from Pune’s Indian Institute of Science, Education and Research (IISER).

The ‘simple’ antibodies are an indication of host response to viral presence but are not that useful to stop further spread of the virus, Bal told .

“Simple presence of antibodies is a clear indication of previous exposure to SARS-CoV2 but does not necessarily guarantee protection from the disease in the absence of neutralising antibodies,” the immunologist added.

“Presence of nAbs in sufficient concentrations and for longer period is the most likely indicator of protection of the inpidual from next exposure leading to illness i.e. COVID-19,” she explained.

Bal also noted that there is no consensus on what levels of nAbs are ‘protective’ from the public health perspective or to ensure that plasma therapy is likely to be useful.

Different sero-survey tests have been conducted in India in the last few months with the aim of indicating the actual number of infected cases in the country.

A sero-survey involves testing the blood serum of a group of inpiduals for the presence of antibodies against that infection to know who has been infected in the past and has now recovered.

Surveys carried across metros suggest that COVID-19 cases are far more than actually reported.

According to Rath, one of the many problems in looking for easy patterns in the serological evidence is that not everyone is using the same antibody tests.

“In fact, all antibody tests in the market are not against the same viral protein target, and some investigators use only one target, others use more. And it is possible that tests differ in their sensitivity,” Rath told .

The scientist also noted that most surveys are reporting people as just ‘positive’ or ‘negative’, and not analysing antibody levels present in the blood.

So far, the limited evidence available does indicate that these antibody tests seem to correlate with “protective” antibody levels too. However, there is not much that can be said to inpidual people about their risk of reinfection or their level of protection.

Different studies, including one published recently in the Journal of Clinical Microbiology, have also suggested that people infected with COVID-19 develop neutralising antibodies that can protect them from reinfection.

However, reinfection cases reported recently from across the world have dented that optimism.

Shining more light on the issue, Bal said reinfection of an inpidual does not mean he or she becomes ill with COVID-19.

Even the presence of enough nAbs capable of neutralising a variant virus will not necessarily prevent infection, said Bal. However, in all probability, such a person with ‘protective immunity’ is likely to handle subsequent infections — including what is currently reported as reinfection — better and with less morbidity than otherwise.

“Reinfections should not be equated with disease due to repeat exposure to the same or related virus,” she said, adding that the recent case of reinfection in the person in Hong Kong was discovered due to screening test rather than symptoms.

While it is not clearly known whether people who generate antibodies against SARS-CoV-2 are protected from reinfection, scientists also don’t know how long those antibodies persist.

A study published in the NEJM journal on September 1 found that antibodies against the new coronavirus endure in the body for four months after infection, countering earlier evidence suggesting these important immune molecules disappear quickly.

The study measured the levels of SARS-CoV-2 antibodies in the blood of roughly 30,000 people, including more than 1,200 who had tested positive for the virus and recovered from COVID-19 in Iceland.

Around 90 per cent of the recovered people had antibodies against the virus.

“Based on the Iceland study, we know that antibodies generated by natural infection can last for four months, maybe longer,” said Bal.

At the moment, there is no idea what percentage of previously exposed people will be susceptible to antibody mediated enhancement of the disease (ADE) when re-exposed to a variant of SARS-CoV-2 or a related virus, she added.

ADE is a phenomenon in which the binding of a virus to antibodies enhances its entry into host cells followed by its replication. It is a general concern for the development of vaccines and antibody therapies.

Rath noted that the Iceland study seems to be quite thorough in many respects, and shows antibody persistence till about four months.

“Is this going to be the case everywhere? I have no guess to offer I am afraid… As far as disease progression in communities goes, the antibody evidence does tell us how much the virus has spread and in which locations-communities, although we need to do much more detailed and repeated sero-surveys to be able to learn anything more than ‘it has spread quite a bit, or maybe a lot’,” Rath said.

Most patients who recover from coronavirus retain antibodies for at least 5 months: Study

NEW DELHI: A majority of inpiduals recovering from mild or moderate Covid-19 develop a robust antibody response that lasts for at least five months, according to a study published in the journal Science.

While most studies so far have found that antibodies to the novel coronavirus go away quickly, this new study conducted at the Icahn School of Medicine at Mount Sinai in New York found the opposite.

“The strength and duration of immunity after viral infection is important for informing decisions on public health preventive measures, for judging the effectivity of convalescent plasma for treating sick inpiduals and for predicting the efficacy of vaccines. A single study should not trigger a premature celebration — we need to watch carefully as more data helps us understand the natural history of Covid-19,” said SP Kalantri, professor of medicine at the Mahatma Gandhi Institute of Medical Sciences in Sevagram, Maharashtra.

The Mount Sinai study revealed that more than 90% of the people who were mildly or moderately ill produced an antibody response that’s strong enough to neutralise the virus for several months.

“Our data suggests that more than 90% of seroconverters make detectible neutralising antibody responses. These titers (levels) remain relatively stable for several months after infection,” the authors of the study said. A seroconverter is one that has or is undergoing production of antibodies.

The findings were based on the data of 30,082 inpiduals, who were screened within the Mount Sinai Health System from March to October.

The scientists used an antibody test called enzyme-linked immunosorbent assay (ELISA) to detect the tell-tale spike protein that enables the virus to attach itself to human cells and gain entry. The test detects the presence or absence of antibodies to SARS-CoV-2, the virus that causes Covid-19, and measures the level of antibodies.

The study found that of the 30,082 positive samples, the vast majority had moderate-to-high levels of anti-spike antibodies. The levels ranged from 1:80 for 690 inpiduals (2.29%) to 1:2,880 for 11,610 inpiduals (38.6%).

According to the researchers, this indicated that a moderate level of antibodies is retained by most people five months after the onset of symptoms.

The study has come as a breather after earlier research showed that antibodies decline rapidly. A recent study from Imperial College London also found that antibodies against Covid-19 declined rapidly in hundreds of thousands of people across England.

“The (Mount Sinai) study findings differ from a previous study from China that showed that a large number of inpiduals who recovered from SARS-CoV-2 infection had waning titers of antibodies within eight weeks of infection. That study also showed that in as many as 40% of asymptomatic inpiduals, antibodies disappeared after 8 weeks of infection,” said Kalantri.

A public health expert said that an elaborate study is needed to substantiate the findings of the Mount Sinai study.

Bharat Bio leads CSIR project to develop human antibodies

HYDERABAD: Global vaccine manufacturer Bharat Biotech has received sanction from the Council of Scientific and Industrial Research (CSIR) to lead a project to develop human monoclonal antibodies as therapy for Covid-19 infections.

This programme brings together academia — National Centre for Cell Science, Indian Institute of Technology, Indore, and industry – PredOmix Technologies and Bharat Biotech, in a collaborative mode for a public health emergency.

Though efforts were underway for the development of drugs and vaccines for controlling the Covid-19 pandemic, they were slow with expensive processes coupled with uncertainties, Bharat Biotech said in a press release on Friday.

Saying that an alternate therapeutic regimen for early deployment was critical, the Hyderabad-headquartered vaccine maker said, “The present project aims at such an alternate therapeutic regimen by generating highly effective and specific human monoclonal antibodies that are capable of neutralizing the SARS-CoV2 virus.” Such virus-neutralising antibodies can block the spread of infection by binding with the virus and rendering it ineffective. Monoclonal antibody therapy is a highly effective and safe method, it said. “The purpose of vaccination is to protect the healthy against future infections and it alone may not provide the complete solution. We feel the monoclonal antibody therapy will provide a viable option,” said Dr Krishna Ella, CMD of Bharat Biotech.

Israel and Netherlands recently announced development of virus-neutralising antibodies. However, the approach of CSIR’s project was to develop a powerful cocktail of neutralising antibodies that can also simultaneously block mutational variants of the virus, said Dr Ella.

“We are fast-tracking the development process, to make the antibodies available within the next six months, and thus improve the treatment efficacy.”

Bharat Biotech, which has a track record in identifying potential viral threats, has so far developed 10 different viral vaccines and has till date delivered more than 5 billion doses of viral vaccines, including anti Rabies vaccines.

IAVI, Merck KGaA, Serum Institute join hands to develop monoclonal antibodies for Covid-19

Serum Institute of India and not-for-profit scientific research organisation IAVI have joined hands with science and technology company Merck to develop SARS-CoV-2 neutralising monoclonal antibodies (mAbs).

A phase-I clinical trial is expected to start in early 2021. Serum Institute will lead global manufacturing as well as commercialisation in low- and middle-low-income countries, including India, if the antibody candidates show efficacy in clinical trials, either as a single antibody or a potential combination, the companies said in a joint statement.

( Originally published on Oct 22, 2020 )

If previously COVID-19 infected, single Covaxin dose draws same antibody response as two doses

A single dose of Bharat Biotech‘s Covaxin in previously COVID-19-infected inpiduals elicits a similar antibody response as obtained with two doses of the vaccine in those without a previous history of the disease, according to an ICMR study. The study was published in the Indian Journal of Medical Research on Saturday.

“If our preliminary findings are confirmed in large population studies, a single dose of BBV152 vaccine may be recommended to previously confirmed SARS-CoV-2 infected inpiduals so that the naive inpiduals could attain the larger benefit of a limited vaccine supply,” it said.

India’s first indigenous COVID-19 vaccine Covaxin, codenamed BBV152, was approved by the government for emergency use in January. Two doses are given with a gap of four to six weeks.

The study was undertaken to examine SARS-CoV-2-specific antibody responses after day zero (baseline, before vaccination), day 28 plus/minus two days post-first dose (month 1) and day 56 plus/minus two days post-first dose (month 2) of BBV152 in a group of healthcare professionals as well as frontline workers.

The antibody response of inpiduals with confirmed pre-vaccination SARSCoV-2 infection was compared with those inpiduals without prior evidence of infection.

As a part of the study, blood samples were collected from 114 healthcare professionals and frontline workers who received Covaxin at vaccination centres in Chennai from February to May 2021.

“Overall, good vaccine-induced antibody responses were seen in prior SARS-CoV-2-infected inpiduals, except in two, who received a single dose of BBV152 vaccine that was similar to antibody responses seen after a two-dose vaccination course administered to infection-naive inpiduals,” the study stated.

“Our results in a varied group of healthcare professionals and frontline workers lend support to the previous studies (albeit mainly focused on mRNA vaccines) that increased levels of SARS-CoV-2 binding and neutralizing antibodies are present after a single vaccine dose in previously infected inpiduals and are comparable to the levels seen after two doses in those without prior infection,” it added.

The study offers evidence in support of public health-oriented and immunologically sustained vaccine strategies.

AstraZeneca, U.S. agree 500,000 more supplies of COVID-19 antibody cocktail

AstraZeneca

will supply up to half a million extra doses of its experimental antibody-based COVID-19 combination therapy to the United States, in a bright spot for the company after more governments suspended use of its vaccine over safety fears.

The antibody therapy, which has yet to be approved by U.S. regulators, is designed to treat the disease rather than prevent it like the vaccine, which several countries have stopped using while reports of blood clots in some people are investigated.

The Anglo-Swedish drugmaker said on Tuesday the $205 million U.S. extension for 500,000 antibody doses builds on a contract agreed with government agencies in October for initial supplies of 200,000 doses of the antibody cocktail, AZD7442.

The treatment is a combination of two monoclonal antibodies, London-listed AstraZeneca said, adding that the new agreement is contingent on an emergency use approval by the U.S. Food and Drug Administration.

“The US Government’s support is critical in helping accelerate the development of AZD7442,” AstraZeneca Chief Executive Pascal Soriot said.

The total value of the deal now stands at $726 million for up to 700,000 doses. AZD7442 is being evaluated in late-stage trials, the company said, adding that it currently does not expect any changes to its 2021 forecasts due to the deal.

While AstraZeneca has undergone a rollercoaster ride with its COVID-19 vaccine, it has been working on developing new treatments and repurposing its existing drugs to prevent and treat coronavirus infections.

Monoclonal antibodies, such as the ones being used in AZD7442, are synthetically manufactured copies of the human body’s natural infection-fighting proteins, and are already being used to treat some types of cancers.

A series of issues have bogged down the drugmaker’s vaccine rollout: including pauses in trials, questions over the most effective dosing, and supply problems. Share gains from optimism around the cheap and easy-to-ship shot have also been decimated.

On Tuesday, the stock was up 1.5% at 7,090 pence in early trading. At its peak in July last year, the company hit 10,120 pence.