COVID-19: Vaccine trials and antibody testing provide fresh hope
At Medical News Today, we have been looking at how scientific advances are providing much-needed hope during the COVID-19 pandemic. This Special Feature discusses the recent progress of vaccine clinical trials and other ways in which researchers hope to fight the new coronavirus.
What are the shining beacons at this uncertain time? This is a question that we, at MNT, have been asking ourselves.
To try to answer it, every other week, we review the latest coronavirus research and present our readers with the most promising and reassuring findings from scientific studies.
Last fortnight, in the Special Feature entitled COVID-19: Vaccine may be ready by fall and other reasons for hope, we spoke about how researchers from the University of Oxford in the United Kingdom planned to kickstart clinical trials for a new vaccine against SARS-CoV-2, hoping to have it ready by fall 2020.
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In this Special Feature, we explain how those plans have progressed and look at other steps that specialists have been taking to put an end to the pandemic.
First volunteers enter U.K. vaccine trial
On April 23, the University of Oxford announced the launch of the U.K.’s first human trial for a SARS-CoV-2 vaccine.
The researchers expect that the trial will involve about 1,100 volunteers, half of whom will receive the actual experimental vaccine while the other half receive a vaccine for meningitis, acting as controls. The participants will not know which of the two they have received.
The experimental vaccine should stimulate the immune system to recognize and react to SARS-CoV-2’s spike protein, which allows it to enter and infect healthy cells.
A week ago, the first two volunteers received the inoculation. Both of them are scientists who were keen to contribute in some way to the efforts to fight the new coronavirus.
One of the volunteers, Edward O’Neill, Ph.D., who works in the department of oncology at the University of Oxford, has said in an interview that taking part in the early stage of this clinical trial “just seems like the right thing to do, to ensure that we can combat this disease a little and get over it a lot faster.”
The other pioneering participant, Elisa Granato, Ph.D. — from the department of zoology at the university — has expressed a similar sentiment, saying, “I’m a scientist, so of course I want to try and support science […], and since I don’t study viruses, I felt a bit useless these days, so I felt this [taking part in the trial] is a very easy way for me to support the cause.”
A few days after getting the shot, Granato sent a public message reassuring everyone that she was doing well.
Prof. Sarah Gilbert, who is from the Jenner Institute for Vaccine Research in Oxford and spearheaded the research leading to this trial, has said that she trusts that the vaccine will be a successful endeavor:
“Personally, I have a high degree of confidence in this vaccine.”
The researchers expect that it will take 2–6 months to confirm whether the vaccine is safe and working as they hope that it will.
Biotech experiments with inactivated virus
Recent reports indicate that scientists around the world are currently experimenting with eight different types of possible vaccines for SARS-CoV-2 and that researchers are working on at least 90 vaccines right now.
The one that the University of Oxford researchers are trialing is protein-based. It contains an inactivated or weakened virus — in this case, an adenovirus — that acts as a “support” for the SARS-CoV-2 spike protein and should trigger a response from the immune system, “teaching” it to react to that protein.
Another type of vaccine uses inactivated versions of SARS-CoV-2 but has a similar end goal: to “teach” the immune system to identify and fight the virus.
On April 19, researchers associated with the Chinese biotechnology company Sinovac Biotech reported having successfully inoculated rhesus macaques with inactivated SARS-CoV-2, protecting them from the new coronavirus, which, according to some scientists, could affect nonhuman primates as well as humans.
In the preliminary study — the results of which they made available online in preprint form — the scientists tested their inactivated SARS-CoV-2 vaccine, which they call PiCoVacc, in a group of eight rhesus macaque monkeys.
This experiment followed previous tests in mice and rats. When it came to the rhesus macaques, the researchers chose them because, they say, this species can develop COVID-19-like symptoms following infection with SARS-CoV-2.
The researchers report delivering the experimental vaccine intramuscularly to the monkeys three times, in either medium (3 micrograms [mcg] per dose) or high (6 mcg per dose) doses each time.
At 7 days after infection with the virus, the rhesus macaques that had received the high doses of the vaccine showed the best results, the researchers say. None of these animals had a detectable viral load in their pharynx or lungs at this point.
Commenting on these results, Prof. Florian Krammer from the Icahn School of Medicine at Mount Sinai in New York has said: “I like it. This is old school, but it might work.”
“What I like most is that many vaccine producers, also in lower-middle-income countries, could make such a vaccine,” he added.
A cancer therapy tool may come in handy
Recent research from the University of California, Los Angeles and the Parker Institute for Cancer Immunotherapy in San Francisco, CA, also suggests that a tool that scientists use in cancer therapy could help researchers who are developing SARS-CoV-2 vaccines. This study paper is also available online in preprint form.
According to its authors, a computational tool designed to aid in the development of cancer vaccines could also come in handy in figuring out the best approaches to a SARS-CoV-2 vaccine.
This tool, they note, could help researchers understand more about how killer T cells — a type of white blood cell that plays a key role in the immune response — may react to SARS-CoV-2.
It could do that by revealing whether or not various vaccines are likely to be effective in a diverse human population.
In a recent short commentary in Nature Reviews Immunology, Miriam Saffern, who is studying for a doctoral degree at the Icahn School of Medicine at Mount Sinai, emphasizes the relevance of initiatives such as this.
“T cell vaccines against SARS-CoV-2 are being developed at a rapid pace,” she writes, “but it is imperative that the proteins or peptides they deliver bind to a large variety of HLA [human leukocyte antigen] haplotypes in the global population.”
An individual’s HLA haplotype refers to a set of genes that helps their body distinguish its own proteins from those that viruses and bacteria have made.
HLA haplotypes vary among different people, so being able to tell whether or not the proteins in a vaccine bind to a variety of these might be a good indication of whether the vaccine would be able to serve a diverse population.
“This publicly available dataset [from the preliminary study] will be an important resource to guide vaccine development.”
– Miriam Saffern
Antiparasitic drug shows promise
Researchers are also investing a lot of effort into trying to come up with a targeted therapy to eliminate SARS-CoV-2 in people who have already contracted the virus.
Scientists have been experimenting with both new and old drugs to try to find the most promising avenues.
According to a new study published online ahead of print in the journal Antiviral Research, ivermectin, an existing antiparasitic drug — a treatment for infestations such as those that head lice cause — shows promise as a treatment.
In laboratory experiments, investigators from the Royal Melbourne Hospital and Monash University, also in Melbourne, Australia, infected cell cultures with SARS-CoV-2 isolates before exposing them to a dose of 5 micromoles of ivermectin.
This experiment effectively eliminated the virus from the cell cultures in a short amount of time, which led the researchers to conclude that ivermectin may deserve more attention as a potential therapeutic candidate for COVID-19 in the future.
“We found that even a single dose could essentially remove all viral RNA by 48 hours and that even at 24 hours, there was a really significant reduction in it.”
– Lead researcher Kylie Wagstaff, Ph.D.
According to Wagstaff, a readily available drug could fast-track global efforts in curbing the pandemic.
“When we’re having a global pandemic, and there isn’t an approved treatment, if we had a compound that was already available around the world, then that might help people sooner,” she says.
E.U. validate antibody test
Besides the efforts to find an effective way to prevent SARS-CoV-2 infections or treat COVID-19, the disease that the virus causes, scientists have also been hard at work on something else.
Around the world, researchers have been looking for accurate, safe, and effective methods of screening people for antibodies to the new coronavirus — a marker signifying that they have overcome a SARS-CoV-2 infection.
Antibodies might also show who has acquired a degree of immunity to the virus, however temporary, although the World Health Organization (WHO) caution that there is “no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.”
Still, a safe and accurate antibody test that is widely available could help decision-makers better understand the dynamics of the viral spread and the state of the outbreak at a particular time in a particular place. This information could help authorities gradually lift lockdown measures or restrictions, where possible.
It seems as though such a test may soon be reaching at least some countries in Europe. According to recent reports, the European Union (E.U.) have now certified an antibody test produced by Abbott Laboratories as safe to use.
The test screens for the presence of the IgG antibody, which emerges as an infection is waning and remains present for some time after it has cleared.
According to the manufacturer, this antibody test has “demonstrated specificity and sensitivity of greater than 99% 14 days or more after symptoms started.”
As laboratories in the U.K. already possess a significant number of machines that would allow them to run this antibody test, Abbott are now negotiating to provide tests to this country.
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