Home » Health » Monkeys and ferrets provide the necessary guidance for the COVID-19 vaccine race

Monkeys and ferrets provide the necessary guidance for the COVID-19 vaccine race

“We’re essentially doing a great experiment,” said Ralph Baric, a coronavirus expert at the University of North Carolina at Chapel Hill, whose laboratory is testing multiple vaccine candidates on animals.

Even though companies are recruiting tens of thousands of people for larger vaccine trials this summer, scientists behind the scenes are still testing ferrets, monkeys, and other animals in the hope of finding clues to these fundamental questions – steps that would have been completed in a pre-pandemic period .

The global race for a COVID-19 vaccine boils down to some critical questions: To what extent do the shots have to strengthen a person’s immune system in order to really work? And could it do harm if you turn it wrong?

In animals, “we can do autopsies and specifically look at their lung tissue and get a deep look at how their lungs are responding,” said Broderick.

Animal testing shows scientists how the body responds to vaccines in a way that human studies never can, said Kate Broderick, research director at Inovio Pharmaceuticals.

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The acceleration is necessary to try to stop a virus that has caused a pandemic, killing more than 360,000 people worldwide and shutting down economies. “There is no question that the current strategy carries a higher risk than ever before,” said Baric.

And there is some good news regarding safety as the first animal data from various research teams is trickling out. So far, there are no signs of a worrying side effect called disease enhancement that Dr. Anthony Fauci of the United States National Institutes of Health described as calming.

She is waiting for results from mice, ferrets and monkeys who are exposed to the coronavirus after Inovio’s vaccination. Since no species perfectly mimics human infection, testing a trio expands safety.

An improvement is exactly what the name suggests: very rarely, a vaccine does not stimulate the immune system in the right way and produces antibodies that can not only block the infection completely, but exacerbate the resulting disease.

This happened for the first time in the 1960s when a vaccine against the Respiratory Syncytial Virus RSV, an infection dangerous for infants, failed. More recently, efforts to vaccinate mosquito-borne dengue fever have been hampered.

And some attempts to vaccinate SARS, a cousin of COVID-19, seemed to improve animal testing.

Fast forward to the pandemic. Three recently reported studies in monkeys tested various COVID-19 vaccination approaches, including images from Oxford University and Chinese Sinovac. The studies were small, but none of the monkeys showed signs of an immune-enhanced disease when scientists later dripped the coronavirus directly into the animals’ noses or trachea.

These researchers found as much virus in the noses of the vaccinated monkeys as in the unvaccinated ones. Although the experiment exposed funds to high concentrations of the coronavirus, it raised worrying questions.

Protection against serious diseases is only a first step. Could a vaccine stop the virus from spreading? The Oxford study raises doubts.

Some of the best evidence that a vaccine might work also comes from these monkey studies. Oxford and Sinovac developed very different types of COVID-19 vaccines. In separate studies, each team recently reported that vaccinated monkeys were protected from pneumonia while monkeys given a sham shot became ill.

“Ferrets develop a fever. They also cough and sneeze, ”said vaccine researcher Alyson Kelvin from Dalhousie University in Canada.

The new corona virus is deposited in the lungs of monkeys, but rarely makes them super sick. Ferrets – the preferred animal for developing flu vaccines – can tell if potential COVID-19 vaccines could stop the spread of viruses.

The type of vaccine – how it targets the “spike” protein that coats the coronavirus – can make a difference. Researchers at the Beth Israel Deaconess Medical Center in Boston designed six different prototype vaccines. Some have only partially protected monkeys – but one has completely protected eight monkeys from signs of the virus, said Dr. Dan Barouch, who is working with Johnson & Johnson on another COVID-19 vaccine candidate.

Inovios Broderick said: “Let me be honest. We are still not sure what these protective correlates are “- which means which mixture of immune reactions and how much is needed.

Some vaccine manufacturers report promising immune responses in the first people to take the experimental shots, including the production of “neutralizing” antibodies, a species that binds to the virus and prevents it from infecting cells. But there is a problem.

And while COVID-19 poses a great risk to the elderly, vaccines often do not strengthen an older person’s immune system or that of a younger person. So Kelvin also studies older ferrets.

Some evidence comes from the blood of COVID-19 survivors, though “the immune responses between the critically and lightly ill are very different,” added Broderick.

Ultimately, however, the true evidence is not provided before extensive studies are conducted on whether vaccinated people are less likely to get sick than non-vaccinated people.

When vaccinated animals that produce the same neutralizing antibody levels as certain COVID-19 survivors are protected – and people who have been given test doses also produce the same amount – it is a great consolation that your vaccination approach actually works, Kathrin said Jansen. Pfizer Inc. Vaccine Research Director

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The Associated Press’s Department of Health and Science is supported by the Department of Science Education of the Howard Hughes Medical Institute. The AP is solely responsible for all content.

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