Fresh thinking for an old problem

The drive to eradicate polio has spurred the development of high- and low-tech solutions to complex challenges

The tools used to isolate and eradicate wild poliovirus have evolved as the battleground has moved from the schoolyards of 1960s America, to the mountains of modern-day Pakistan and Afghanistan. Thanks to a concerted global effort over more than half a century, today the virus lurks in just a scattering of towns and villages in both endemic countries, yet there remains a significant challenge to eliminate the last vestiges of a disease that as recently as 1988, infected more than 350,000 people around the world every year.

Of all the technological leaps forward, the arrival of the mobile phone and the advent of mobile data collection (MDC) is changing the way polio programmes work, both in- and intra-campaign. Not only does SMS-based training help organisations equip front line health workers with the skills they need to do their job, surveillance teams are reaping the benefits of real-time data collection.

“Mobile data collection saved our life,” says Karim Ismaili, an information management officer with the Global Polio Eradication Initiative (GPEI), a public-private partnership led by national governments and spearheaded by the World Health Organisation (WHO).

“Cell phone technology has made a huge difference"Ismaili works in Jordan, which has been polio-free since 1998, and where health workers with tablet computers gather information on children’s vaccination status and history, as well as any reasons why they might not have been vaccinated. Should the health workers come across any cases of acute flaccid paralysis, they can raise an immediate red flag to enable case investigation and specimen collection, which are critical to detect wild poliovirus circulating in infected areas.

In Pakistan, meanwhile, Rotary International has partnered with a cell phone provider to enable health workers to use supplied phones to record real-time information about the families they meet. Questions include how many children there are in the house, whether those children have ever been immunised, and whether the mother is pregnant.

“This data can be collected and analysed immediately, so we can work out if there are areas that are being missed by immunisation programmes, or children that have not been recorded or are not in the registry, and then we can intervene as needed,” explains Carol Pandak, director of the PolioPlus programme at Rotary International. “Cell phone technology has made a huge difference."

"One of the gamechangers was to provide a label that will tell you if the vaccine is still good"While the vaccine itself has become more effective and cost efficient, preserving and extending the cold chain along which the doses pass from factory to field, has necessitated the adoption of other key technologies. Today clinics in developing nations are equipped with solar-powered vaccine fridges, or Sure Chill fridges that stay cool for up to 12 days without the need for power.

There is room for lower-tech solutions too: donkeys are employed to haul cooler boxes of vaccines into off-grid rural areas, and vaccine vials are emblazoned with simple thermochromic labels that save lives and money.

“One of the gamechangers for the cold chain system was to provide a label that will tell you if the vaccine is still good,” says Pandak. “Even if you can’t read there is a little box and if the vaccine gets too warm then that square turns a different colour and you know that the vaccine is no longer viable. That’s not necessarily a new development but it was hugely significant because it means we aren’t giving out impotent vaccines.”

Researchers have found that using unmanned drones to deliver vaccines in low- and middle-income countries may save money and improve vaccination rates. Cost savings would derive from drones being able to deliver vaccines more quickly and cheaply than land-based methods limited by road conditions and the need for costly fuel and maintenance. And of course, terrain previously considered impassable would be opened up, allowing vaccines into even the most isolated spots.

Should polio be unearthed in one of these remote outposts, the next challenge is to persuade community leaders to allow vaccinations to take place. In order to achieve this, organisations are turning to tried-and-trusted technologies to bridge cultural and knowledge gaps, and persuade mothers and fathers to let their children be immunised.

“In these last stages of polio, we’re working in some of the most remote and sensitive communities, those that might be uncomfortable with people coming in from the outside,” says Pandak. “With this in mind we have developed tools to help people in these communities assess what we are doing, such as the speaking book that we have used in Nigeria and Pakistan. It’s a book about health with some words, but also recorded messages, which means that people can look at the pictures and listen to what’s being said, so even if they can’t read they still get the message.”

Finally, the way that the vaccines are administered is also changing. The first inactivated polio vaccine (IPV) was delivered via injection but within a decade the oral polio vaccine (OPV) had become more widely used. Today, however, scientists are working on the development of vaccine-filled microneedle patches, which can be applied by personnel with minimal training in remote areas. A bridge between the IPV and OPV, the patches are pressed into the skin, at which point the microneedles dissolve, leaving no sharp waste.

The vaccine evolution

The intelligent application of technology has been pivotal to the progress of the campaign to eradicate polio – and began with the development of the vaccine itself. Both the inactivated polio vaccine (IPV) pioneered by Jonas Salk in the 1950s, and the oral polio vaccine (OPV) that came into commercial use the following decade, have been subject to 21st century refinements to increase efficacy and drive down cost.

“After the IPV and OPV were developed, the polio vaccine basically stayed the same for the next 50 years,” says Dr Hiro Okayasu, team leader for research, innovation and product development with the GPEI.

“We needed to change our business model. To eradicate polio completely, we cannot use OPV alone"Since the turn of the new century, vaccines have been developed to target specific serotypes of the disease, and do so with maximum efficiency.

Earlier this year 155 countries, led by the GPEI, switched to the bivalent OPV which targets wild polio types 1 and 3 - and is found to be more than 30 per cent more effective than the trivalent doses that wiped the virus from so much of the globe.

Work is also underway to develop a new, cost-effective IPV that will help prevent a resurgence of type-2 polio, last detected in 1999 but still known to linger in a handful of communities around the world.

“We know, for example, that some parts of Nigeria have type-2, and if this spreads to other countries then it will be a really serious situation,” says Dr Okayasu. “We needed to change our business model, which used to be that everybody gets the OPV, and once we don’t see the polio virus then we stop and that’s it. However we realised that to eradicate polio completely, we cannot use OPV alone, and so since 2008 we have been working to develop affordable IPV.

“We have looked at many options, including reducing the number of doses, and using an adjuvant such as aluminium hydroxide to strengthen the immune response in the patient’s body, halving the amount of antigen you need in each dose,” he continues.

Most promising, he suggests, is the efficacy of intradermal vaccination.

“For a long time we’ve known that the skin has a higher concentration of immune cells, and now we have found that one fifth of a dose given intradermally is as effective as a full dose given intramuscularly. That reduces costs significantly and also will allow us to roll out the IPV more quickly as it’s not a new vaccine that will need to go through trials and regulatory processes, just a new way of delivering an existing vaccine.”