Polio Shmolio

Fantastic news, science fans! We are on the verge of extinctifying (definitely a real word) another species!! But don't feel blue, it's not a cute little rainforest critter or a beautiful tropical coral, it's the dreaded polio virus. Most of us in the west below a certain age won't really know what polio even is, that's because we all get vaccinated against it when we're babies and it doesn't exist here anymore. If you have an old person to hand and a spare four or five hours you can say the word polio at them and they will be able to give you a million stories about the terror that it used to instil in the population. Every street in the country had a child in a wheelchair left withered and paralysed by the disease, every hospital had a room full of iron lungs to help the most severely affected children breath and every neighbourhood had a grieving family.

Poliomyelitis, to give it its full name, is caused by an enterovirus only 30 nanometres in diameter. It is spread by the usual faecal-oral route and multiplies aggressively in your intestines; in some cases it will spread to your central nervous system and wreak havoc in the form of paralysis. There are three strains of the virus, simply called one, two and three; polio virus 2 was last seen in 1999, meaning we have already eradicated one strain from the planet.

In 1988 most western countries had successfully become polio free but it was still endemic throughout most of the world, indeed there were 350,000 cases in 125 countries that year. In 2014 there were 134 cases in just three countries; Nigeria, Pakistan and Afghanistan. The reason I'm writing about this now is that Nigeria has actually just gone one whole year without a new polio case, an astonishing achievement given the difficulties they face there. For example, there were the usual African scare stories and propaganda about the vaccine supposedly containing the HIV virus; and, sadly, nine health workers were killed by Boko Haram militants two years ago for having the temerity to try to help people.

The massive, worldwide vaccination program that has given us this success has been spearheaded by the World Health Organisation, UNICEF, Rotary International and the US Centers for Disease Control. Together they have spent $10 billion immunising 2.5 billion children and the final eradication plan is to have the entire globe free of the polio virus by the end of 2018. Although there has been enormous success so far we must not get complacent. Polio only shows symptoms in 1 in 200 people and so the vast majority of cases wonder around quite merrily spreading the disease without ever knowing it. It is estimated that if just one child were missed and was left to spread the virus then within a decade we would be back to a level of 200,000 new cases per year.

It can be done, though; this wouldn't be the first time we have deliberately eradicated a deadly virus. In 1977 there was the last ever case of small pox; it now only exists in a couple of laboratories around the world. So there is hope, but the consensus seems to be that the last chapter is always the most difficult one. To ensure success a final push is being made to try to meet the 2018 target. Looking at their own timeline they seem to be about 12 months behind schedule so the end of the decade may be a more realistic target. In any case, when it happens it will be a huge success story for the planet and something that we as a people can be proud of; and it's all thanks to science.

Ebola: A Vaccine

Ebola is a genuinely scary disease. After the outbreak in west Africa earlier this year there must be very few people out there now who haven't heard of it. It is a part of the haemorrhagic fever cluster of diseases, causes multiple organ fever and for you to essentially start leaking your insides out of every orifice you have. It is spread via contact with infected bodily fluids and results in death in about a half of people in most outbreaks, although the recent one had a mortality rate of 70% of those infected. It is a viral infection named after the Ebola river in the DRC near where the first outbreak occurred in 1976.

The current, now fading, outbreak has wreaked a terrible toll. 11000 people have died; normal life in entire areas of Guinea, Sierra Leone and Liberia has been shut down. The seeds of fear and distrust have been sown in communities having a deep psychological effect that few people have even begun to try to understand yet. Now, though, for the first time, there could be hope. A vaccination has been produced by the Public Health Agency of Canada and a field trial has been completed, with promising results (published in The Lancet).

They used a strategy known as ring vaccination. This is where those in immediate contact with a symptomatic individual; friends, family, colleagues, neighbours; are vaccinated thereby forming a 'ring' of immunity around the test case. There were two groups in the study; group one was where all individuals in the ring were immediately vaccinated without delay; group two were also all vaccinated but only after a delay of 21 days. Previous, smaller trials had proved so effective that it was considered unethical to deny some people the vaccination.

In the second group, where treatment was delayed, there were 16 subsequent cases out of 3528 vaccinated. In the first group, that had immediate treatment, there was no cases at all out of 4123 people. That is a fantastic result for a vaccine that only began development a year ago; normally it would take a good decade to make that sort of progress. The trial took place in Guinea and now the powers that be are quickly trying to get through the red tape required to get the vaccine into Liberia and Sierra Leone. This might not be the end of the story, though; there are 5 species of ebola virus and we don't know how well the vaccine will work on each of them; we would also need to test more people to gain a fuller understanding of the potential side effects; and technically this isn't a licensed treatment yet, but everything is being done to smooth its path to widespread use. Plus, the vaccine has to be stored at -80 degrees Celsius, which isn't always an option in the poorly funded and equipped countries where ebola is prevalent. On the upside, GAVI, the global vaccine alliance, has pledged $390 million dollars to getting the vaccine to where it needs to be. There are also other vaccines in the pipeline which, together, may spell the end of outbreaks on the kind of devastating scale we have seen in the last year.

Electronmicrograph of an ebola virion. Image courtesy of the Centres for Disease Control