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Why do vaccine trials take so long?

It can even take a decade to find a suitable formulation against a certain disease, so reaching the final phase of trials in a matter of months is "unbelievably quick", says top scientist

AstraZeneca - Why do vaccine trials take so long?

Billions of dollars are being poured in the research for COVID-19 vaccine candidates, deemed as the most viable solution to draw a line under the pandemic.

The aim is to create the so-called ‘herd immunity’, but to do so it is believed 60-70% should be vaccinated.

READ: Coronavirus: What’s happening in the labs of pharma companies worldwide

However, immunising billions of people will take months – and we don’t know how long it will be before finding a formulation that works without major side effects.

Vaccine development is normally a long-term commitment.

They are in development for five or six years before being tested on humans: first scientists identify a suitable antigen (a molecule triggering an immune response), then they see whether it is safe and functional on animals, usually mice or monkeys.

To gain approval, formulations then need to go through three phases of trials in humans.

The first one, usually on 30-40 people, is to determine dosages and potential side effects, while the second phase moves on to a few hundred individuals to investigate efficacy.

The last stage confirms findings on thousands or tens of thousands of participants, as well as testing whether there are any side effects in certain segments of the population.

Covid is an exception

During the pandemic, regulators have allowed covid-related projects to get through experimental stages quicker, while those vaccines that are now being tested on humans used existing formulations with a ‘coronavirus twist’.

Such acceleration had already been seen during the Ebola outbreak in 2014: when it began, Ebola vaccines had already been tested on animals, though not on humans.

Months after the disease appeared, several trials had started, with the first phase 3 of one of them beginning in March 2015.

The Oxford candidate

The UK government has pledged hundreds of millions in funding for various vaccine projects, including the creation of the Vaccines Manufacturing Innovation Centre, scheduled to open in summer 2021.

One of the most advanced candidates is ChAdOx1 nCoV-19, a high profile consortium led by Oxford University.

The final phase of trials, set to start later in the summer, will involve 10,000 volunteers in 18 centres across the UK.

Half of them will receive ChAdOx1 nCoV-19, while the other half will receive a jab for meningitis that will be used as a comparison.

To call it a success, 30 to 50 of the participants receiving the coronavirus vaccine need to have been infected by the virus without getting sick.

The ‘human guinea pigs’ will have to report on any symptoms that may arise in the four weeks after the administration, attend follow-up visits, take swab and blood tests.

Healthcare, frontline and support workers will be prioritised as volunteers over those who work from home because they come into contact with more people in their daily routine.

The trial could take between two and six months depending on how many cases there are in the communities where the centres are located.

Saul Faust, Professor and Director of the Southampton NIHR Wellcome Trust Clinical Research Facility, highlighted the importance of spreading the trial across the country.

“We need to have a national network, which the National Institute for Health Research (NIHR) is developing, whereby we can deploy a number of vaccine trials one after the other and have people immunised all over the country, so that as pockets of disease pop up and down we capture the potential for people to have COVID-19,” he told Proactive.

“The bit that takes time is to wait for COVID-19 to happen in the population… Maybe the effect of easing lockdown quickly will cause a second wave or pockets of disease in the next weeks that will lead us to answers more quickly.”

An unbelievably quick endeavour

To develop a candidate and recruit thousands of volunteers in a matter of months was “unbelievably quick”, he pointed out.

In fact, the first phase involved 1,000 volunteers rather than the usual 40 seen in vaccine trials, in an enormous effort from all parties involved.

But only a few vaccine candidates usually make it to commercialisation.

That’s a risk that researchers at Oxford, alongside their supporting organisations, have factored in.

"Of course, with this decision comes a risk but it's a financial risk and that financial risk is the vaccine doesn't work,” Pascal Soriot, chief executive at AstraZeneca PLC (LON:AZN), told the BBC last week.

“Then all the materials, all the vaccines, we've manufactured will be wasted."

The FTSE 100-listed firm has bet all on the Oxford candidate, having boosted capacity to produce 2bn doses.

The pharma giant will not receive a profit during the pandemic, but expenses are expected to be offset by funding by governments.

The current order is for jabs of the 10,000 participants of the trial beginning in September, while the world awaits results of the second phase.

Tens of companies and organisations worldwide, including Imperial College London, Novavax Inc (NASDAQ:NVAX), GlaxoSmithKline PLC (LON:GSK) with Sanofi, Moderna Inc (NASDAQ:MRNA) and Pfizer Inc. (NYSE:PFE), are developing their own candidates.

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