He signed up for a trial of a vaccine that’s never been used in humans. Here’s why.

In fact, it is precisely these questions that help us answer them.

Sean helps us all find out if it's safe by putting your hand first and voluntarily. With that injection, Sean had become a critical part of the fastest moving vaccine trials in world history, a vaccine against Covid-19.

Advertisement

During a pandemic, the press is understandable. In just a few months, the virus has spread to almost every corner of the globe and unfortunately has taken more lives than more wars or natural disasters combined. It is also true that no one on the planet is immune to this; Such is the nature of a novel or new coronavirus. When dealing with all of this, remember that last Thanksgiving, this wasn't even a real concern for people, and not even a topic of free conversation. And now it's the only thing being discussed in hospitals, boardrooms and at kitchen tables every night, often by Zoom. So yeah. The urgent pace is quite understandable, but we need to make sure we can sprint, while also not tripping, falling and getting hurt.

When I recently sat out with Sean at the Emory School of Medicine in Atlanta, where he is studying and I am on the neurosurgical faculty, it may have seemed like a new meeting between student and teacher. If you looked a little closer, but you would notice that we were sitting several feet apart, masks tucked around our necks and raising our voices a little to make sure we could be heard. I really wanted to understand how Sean had decided to volunteer for an experimental vaccine. I wanted to understand how he dealt with and assessed risk. As a dad, I wanted to know what his parents thought.

Sean Doyle has been given his blood as part of a coronavirus vaccine study.

It came as no surprise to me that Sean, despite not being born yet, was familiar with the history of vaccine against swine flu from 1976. In January of that year, a new or new virus began to spread at Fort Dix in New Jersey. Fearing that this new virus could cause a pandemic like the one in 1918, the United States crashed a vaccine through development. Within a year, nearly 25% of Americans had been vaccinated, about 45 million people. However, without enough time to carry out adequate safety tests, devastating side effects began to emerge. Hundreds of people developed Guillain-Barre syndrome, a paralysis that starts in the feet and slowly marches up your body. Several people also died, and for some, a fear of vaccination remains to this day.

Advertisement

"It was definitely a concern," Sean told me, "potentially developing things like Guillain-Barre. It's a risk.

"With this particular vaccine, nobody knows what the chances are. But the potential risks are outweighed, I think, by the potential benefits of this vaccine, because right now there are no major preventative measures to contain this virus."

Advertisement

A bold schedule for a challenging illness

Dr. Amesh Adalja, a senior researcher focusing on emerging infectious disease at the Center for Health Security at Johns Hopkins University, notes that the timeline for this vaccine is fast compared to others. US health officials have said a vaccine could be ready in 12 to 18 months – speed of light in a world of vaccine development.

"Vaccine development is usually measured this year and sometimes even decades," Adalja said. "And there are some infectious diseases that we have no vaccine after decades and decades of work, such as HIV or hepatitis C, for example."

"The only way we're really going to contain this virus is with the vaccine," Adalja said.

Dr. Peter Hotez, a leading expert on infectious disease and vaccine development at Baylor College of Medicine, believes the 12 to 18 month timeline may be wishful thinking.

Advertisement

"I can't think of another example where things have gone so fast," Hotez said. The fastest vaccine ever developed was against mumps. After vaccine inventor Maurice Hilleman isolated the mumps virus from his 5-year-old daughter in 1963, it accelerated the market in four years.

Advertisement
Doing it in a fraction of the time would be a challenge, Says Hotez.

"We certainly try, I mean, that our scientists work day and night in the lab now," he said.

When side effects mean major setbacks

Safety is always crucial, but especially with vaccines. Unlike therapeutics, which are often first tested in people with late stages of a disease, vaccines are given to healthy people to prevent the disease. The risk of causing illness or even death in an otherwise healthy person haunts anyone involved in the coronavirus response.

Dr. Mike Ryan, executive director of the WHO health care program, said in a briefing last month that it needed time to test the new vaccines.

"Many ask: & # 39; Why do we have to test the vaccines? Why don't we make the vaccines and give them to people? & # 39; Well, the world has learned many lessons in mass vaccine use, and that's just one more dangerous than a bad virus, and it's a bad vaccine, "Ryan said. "We have to be very, very, very careful to develop any product that we are going to inject into potentially most of the world's population. We have to be very, very, very careful that we do no harm at first. So that's why people are careful. "

The 1976 swine flu vaccine vaccine is one of the most well-known cases, but there have been recent errors. In 2017, a campaign to vaccinate nearly 1 million children against mosquito-borne dengue virus in the Philippines had to be halted because the vaccine actually increased the risk of severe dengue infection in some people. Ten children died.

In a rush to protect children from an infection that kills 400 million people and kills 22,000 every year worldwide, officials ignored warnings that the vaccine should only be used in people who have already been infected once. Dengue is actually caused by four different viruses, and the first infection is usually mild, while the later infections are more dangerous. In this situation, vaccination of people who had never been infected sometimes increased the risk of complications if they were subsequently infected with another strain.

The second time, America was desperately searching for a miracle cure for a devastating disease

The earliest vaccines, such as the smallpox vaccine used for hundreds of years, involved inoculating people with a real, live virus in the hope that a controlled dose and infection would give immunity. It was a gamble, and many people became very ill or died of such attempts.

Later vaccines used related but less harmful viruses. In the 1900s, scientists learned how to kill or attenuate viruses and bacteria in the lab and use them to vaccinate.

Hotez thinks security controls are better now, but the timeline still presents a challenge.

"The question is, will a year to 18 months be sufficient time to monitor for security?" he asked.

Can we hijack genetic material to get a vaccine faster?

Vaccines are typically first tested in the laboratory and then in animals before coming to three-stage clinical trials. Phase I clinical studies look at whether the vaccine is safe in a few people. The second phase involves several people, who are often given different doses to test whether the vaccine is causing the desired immune response and which dose might work best. The third and final phase gathers data on whether the vaccine really protects people, usually under real conditions.

Because coronavirus is such an overwhelming threat, this meticulous and comprehensive timeline is hugely compressed. Vaccines started testing humans only months into the pandemic, and some tests are run simultaneously on humans and animals. Remember that vaccines work by a simple principle: priming the body's immune system to recognize, attack, and neutralize a bacterial or viral infection.

Vaccine manufacturers got a head start on a Covid-19 vaccine because work had already started on vaccines against two related coronaviruses: severe acute respiratory syndrome or SARS, which infected around 8,000 people and killed nearly 800 before it was stopped in 2004, and Middle East respiratory syndrome viruses or MERS, which cause occasional outbreaks.

So scientists already knew a lot about the mechanism by which this particular virus used the spike protein to enter human cells and how they could inhibit that process.

Covid-19 vaccine study on humans starts as UK warns that restrictions may remain in place for next year

A new approach relies on using genetic material that looks like bits of a microbe and stimulates the body to produce an immune response. There is no chance of accidental infection, because no virus is actually used. For coronavirus, it is hoped that using messenger RNA – the genetic material that guides cells to produce something – will offer the fastest and safest path.

This illustration, made at CDC, shows the spikes that adorn the outer surface of the virus.

In this case, the RNA vaccine would stimulate cells to make the spike proteins that look like bits of coronavirus. If it works properly, after being exposed to the engineered fragments of the virus, the body would be trained to recognize them and be prepared to defend against them should there be a future attack or infection.

RNA vaccines are quick and relatively easy to make, which is why they are already being tested in humans. All a laboratory needs is the genetic sequence of the virus. But no such vaccine has ever been approved for use in the population.

Another, more time-tested approach to fighting coronaviruses is using viral vector vaccines. These use viruses harmless to humans, genetically engineered to carry bits of the target virus – in this case the Covid-19 virus. The harmless virus causes a symptom-free infection, and the immune system learns to recognize the harmful genes.

But while technology means rapid progress, Adalja said they are still new.

They may fail, or cause unexpected side effects.

When it comes to RNA vaccines, there is "no precedent yet for them to be approved for use, and we don't know all about them in terms of how they should behave in large numbers of people and what the side effect profile they may be," Adalja.

It's something Sean Doyle has not only considered, but once before. Back in 2017, he raised his hand to be among the first to be injected with the Ebola vaccine. He was the first year medical student at that time, and watched the first patient in the United States be treated at his medical school, Emory. Sean remembers exactly what led him to participate.

"I remember the fear that killed both the outbreak in West Africa," he said. "The fear of people there and their health, but also the fear of whether the virus can come out of West Africa or spread to other parts of the world."

And while the outbreak was contained before the vaccine trial began, he knew that taking part of the trial meant that if it ever happened again, it could be a vaccine that hopefully would be distributed quickly.

So, as now, Sean knows that there are volunteers like him who expose themselves to greater benefit – no matter what it entails.

"There were conversations that I had with friends and family," he said. "They all expressed concern about getting an experimental vaccine like this where no one knows what the side effects might be. But they relied on my judgment."

CNN's Mallory Simon contributed to this report.

Source link

Leave a Reply

Your email address will not be published. Required fields are marked *