Researchers test vaccines against polio, from a car park


Three dozen volunteers in Antwerp are participating in one of the most complex medical trials ever undertaken, in the hope of eradicating polio for once and for all

Summer-time quarantine

In spite of the hot weather and bright blue skies, 30 people recently volunteered to forgo fresh air and remain confined in closed quarters for almost a month.

The setting for this confinement was “Poliopolis”, a large container park of 66 units on the car park of the Drie Eiken Care Hotel in Edegem, a stone’s throw from the University of Antwerp (UAntwerp). Inside this makeshift facility, these volunteers are helping to test a new vaccine that they hope will eradicate polio. 

Eradication of the polio virus, which can cause paralysis in children, has never been this close. In Flanders, polio was wiped out more than 30 years ago. Thanks to large vaccination campaigns, the number of polio cases around the world has fallen spectacularly, from hundreds of thousands before the 1950s to just 37 in 2016.

In spite of the efforts of researchers and local governments the disease hasn’t been completely wiped out. Some regions in Pakistan and Afghanistan have proved very difficult for medical personnel to reach, and the type of vaccine administered in developing countries carries the very rare risk of causing patients to contract the virus. The Antwerp experiments are aimed at completely removing this risk.

“At the moment, two vaccines are used around the world,” says Pierre Van Damme, the lead researcher on the experiment and a professor in vaccinology at UAntwerp. “One needs to be injected and contains a dead version of the virus. This is the version used in all industrialised nations,” he explains.

“Then there’s the oral vaccine used in developing nations, which contains an active but weakened version of the virus.” The advantages of this vaccine are that it is cheap and that there’s no need for trained personnel to administer it, he explains. “The problem is that one in a million people who take it end up developing the disease.” 

Small risk

Even though one in a million might seem small, this number could imperil the future of vaccination programmes in developing nations. “This year so far we’ve only seen five spontaneous cases in the world,” Van Damme explains. “Developing nations might begin to question the usefulness of funding vaccination programmes that cause roughly the same number of cases as the number of cases that spontaneously occur. We need to make sure the vaccine doesn’t cause any new cases.”

The World Health Organization already advises replacing the orally administered vaccine with the safer, injected version, but that doesn’t mean the oral vaccine shouldn’t be perfected, he explains. “In case of outbreaks, especially in developing countries, there will always be a need for cheap vaccines that don’t require on-site trained personnel to halt its spread,” he says. “We need something that is good to have just in case.”

In case of outbreaks, there will always be a need for cheap vaccines that don’t require trained personnel to halt its spread

- Pierre Van Damme

At Poliopolis, the oral vaccine is being perfected. Two new candidate vaccines containing the active virus are being tested, using genetically stable strains that have been designed to prevent them from mutating and causing the disease, Van Damme explains. “There’s no risk for the volunteers as they were all vaccinated against this type of the virus during childhood.” The specific type was officially declared eliminated from the world in 2015. 

For this reason, the World Health Organization doesn’t want the vaccine to get into the natural environment in any shape or form, hence the extreme security measures at Poliopolis. 

Daily visits

The polio virus is spread through oral contact with the stool of an infected person, with lack of hand hygiene and poor sanitation important contributing factors. For this reason, no physical contact whatsoever between participants and the outside world is allowed during the trial project, which is funded by the Bill and Melinda Gates foundation.

The container village has its own sewage system, which collects all the running water. All the waste is stored and decontaminated to prevent the virus from getting into the environment, making the Antwerp experiment one of the most complex vaccine trials ever undertaken.

The 66 units arrived from the Czech Republic in March, with the first trial period starting early May. The container park is kitted out with a fitness room, a communal kitchen, a relaxation space and individual bedrooms. Two psychologists pay regular visits to ensure that any conflicts between the participants don’t spiral out of control.

Every day, the participants’ stools are examined to verify whether they still contain traces of the virus and whether it remains genetically stable. The active virus cannot normally survive in nature after 14 days, but as a safety measure the participants will have to remain on site until 28 days after they first were administered the oral vaccine.

Van Damme is in daily contact with each of the participants. “So far, everything is to everyone’s satisfaction,” he says.

Photo: Inside this container-park village, 30 volunteers are spending a month in confinement to test a new polio vaccine

© Nicolas Maeterlinck/Belga