Many developing countries are aiming to transition over to the IPV once polio is eradicated and vaccine coverage is high, but currently they still need the oral vaccine (OPV) to provide rapid widespread coverage.
The vaccine-derived polio is what has been reported here in Laos, as well as in Syria and Ukraine this year, and it is entirely due to a lapse in vaccination coverage and is truly a global emergency. The only way to break transmission is to ensure that everyone is vaccinated. You can learn more about the ‘war on polio’ here at http://www.polioeradication.org/
In many developed countries we use the inactivated injectable polio vaccine (IPV) for our vaccine schedule, which is very effective at preventing an individual person from getting polio by giving them immunity in their bloodstream, and does not carry any risk at all of developing vaccine-derived polio. However in people who get only the IPV, the virus can still multiply inside their intestines and be shed in the faeces, risking continued circulation. So IPV is not as effective at maintaining control in the developing world where polio control has to target intestinal transmission.
If there are low vaccination rates, there are much less people with immunity so more people are at risk of developing the disease and more importantly, many thousands more are passing the virus on in a vicious cycle. Even the vaccine-derived virus that circulates can genetically mutate over time because it is cycling through many non-immune people. This has the potential to cause “vaccine-derived polio.”
The problem with polio eradication is we need to maintain very high (>85%) vaccination rates for it to be successful. In many provinces here in Laos where people may be living remote and in severe poverty, many children are still being born at home in villages without any antenatal care or any attendance to health centres/hospitals for their birth. Sadly, political conflicts are also wreaking havoc with the fight against polio worldwide, with vaccination rates tragically dropping in regions of the world affected by war or disaster, such as in Syria, where people are unable to access health centres to get their vaccinations, or in Pakistan for example, where there has been a sense of mistrust of health workers (after CIA spies disguised themselves as polio-health workers in order to gain access to Osama Bin Laden’s compound in 2010).
Also, for several weeks after vaccination, the vaccine virus replicates in the intestine, is excreted in the faeces, and can be spread to others in close contact. This means that in areas where hygiene and sanitation are poor, immunization with OPV can actually result in the “passive” immunization of people who have not been directly vaccinated, further improving immunity rates very quickly. These mechanisms, along with the very low cost of the oral vaccine (about 11 US cents) and the fact it is so easy to give to many people very quickly, has made the oral vaccine the first choice for emergency/developing nation settings.
Also, because OPV is swallowed and absorbed in your intensines, it produces a local immune response in the lining of the intestines. In the event of infection, these antibodies limit the multiplication of the wild poliovirus inside the intestine. This intestinal immune response to OPV is thought to be the main reason why mass campaigns with OPV can rapidly stop person-to-person transmission of wild poliovirus. In other words, if an immunised person comes across a ‘wild-type poliovirus’, because they already have immunity from this ‘vaccine poliovirus’ within their intestines, the ‘wild’ poliovirus cannot multiply and hence cannot spread to others.
The most efficient way to vaccinate hoardes of people against polio in a short time to ensure high protection (particularly in densely populated, developing countries) is to use the oral polio vaccine (OPV), which involves a few small drops of a laboratory-derived weakened form of the virus in your mouth. OPV produces antibodies in your blood so that, in the event of infection, these antibodies protect against paralysis by preventing the spread of wild poliovirus to the nervous system.
Less than 1% of people who are infected with a polio-virus will actually show symptoms, but for those that do show symptoms, the effects are devastating paralysis and probably death. A single case of paralysis or death from polio can mean up to 2000 people in the vicinity are actually infected and are spreading the disease silently, hence even just one case of polio anywhere in the world is of dire concern.
1 December 2015
I have already seen one child here in Luang Prabang with sudden paralysis, thankfully it was not actually due to polio, but seeing her on the ward in her wheelchair has reminded me about the global ‘war’ on polio. Polio transmission & control is complicated and is currently in a highly fragile stat of flux due to poverty, politics and war. I shall try to summarise it in these next few posts as best I can. Poliovirus is transmitted through ingesting things contaminated with the excreta of an infected person (eg. infected food, water, obviously more common in places where there is poor hygiene & sanitation.) Somebody who is infected with will polio will have a rapid multiplication of the virus in their intestine and then they excrete it, again passing it onto many others.
A tragedy: a case of Polio in Laos in 2015.
Just before I left Australia to come here to Laos, I received an email from the global surveillance health news alert service that we use at Capstone Health Travel Clinic, and I was disappointed to find out that on September 11 this year, Laos’ first death from polio since 1993 occurred. The child experienced a sudden acute paralysis and only 5days later had died. The global fight to eradicate polio for good has been an incredible feat of co-ordination between many countries and until recently success has been within our grasp, with Pakistan and Afghanistan being the only 2 countries reporting cases of wild-type polio in the last year, however global political unrest, war and disastrous social circumstances causing fractures in global immunisation coverage, have seen cases of polio being reported from Mali, Ukraine and now Laos.
30 November 2015
One of the children we've been caring for was a baby that was so malnourished that their blood count (hemoglobin) was only 17, literally about 1/8th of what it should be, it's incredible that this child has even survived and it is testament to the high level of co-ordinated care, even in a resource poor setting, provided by the Lao Friends Hospital. It's impossible to not get attached to the kids, there's some you just want to hang out with all day, for example another little guy that I've come across during this trip, pictured here, who despite his long-term illness is always cheering up the whole ward wth his contagious smile.
26 November 2015
According to some estimates, at the current rate it will take more than 100 years to clean up all the remaining unexploded ordinance from Laos &more than 100 Laotians become victims of these landmines/bombs annually. This is truly shocking & I must admit I didn't know this until I arrived. We all hear about Cambodian cleanup efforts, but what about Laos, the forgotten nation? Laos' Health statistics also prove that healthcare in this country has been largely 'forgotten' until recent times. The World Health Organisation is severely lacking statistics for this country but we know that childhood death & illness under the age of 5 in particular is alarming. The Lao Friends Hospital for Children, through service provision, medical training & public health measures, is aiming to give the kids of Laos a chance at a healthy future. Im honoured to be over here with this incredible team of both expat and local staff. This is the journey I'll share with you in the coming weeks & hopefully years!
23 November 2015
In the two short weeks I've been here so far, I've already seen so many children receive essential and compassionate care the team at Lao Friends, for everything from the 'run of the mill' pneumonias and gastro that affect children worldwide, to illnesses either specific or much more severe in the tropics: dengue fever, typhoid, tuberculosis, chronic extensive osteomyelitis, severe thalassemias, parasitic diseases, chronic developmental issues and a devastating amount of severe malnutrition.
21 November 2015
The week that I arrived they were just about to open their emergency department for the first time, and hence they had visiting professionals such as paediatric emergency physicians from Australia and a general surgeon from the USA to help deliver workshops to the local staff that will be manning the department 24/7, on topics such as emergency airways, burns management, and suturing wounds. It was 'all hands on deck' & I helped the team run a training scenario based on septic shock. The emergency department opened just last week and it has already been a very busy start, with many children presenting with respiratory infections and many other pathologies requiring urgent care. It's been a really exciting time to be a part of the Lao Friends Hospital project, which is still in its infancy. Everyone is working really hard to provide the best level of care that we can, and I feel privileged to be working with such a diverse and dedicated team.
20 November 2015
Wednesday 18th November 2015. I touch down in Luang Prabang, the ancient capital of Lan Xang (land of 'one million elephants'), otherwise known as Laos, a long & slender landlocked nation nestled between the borders of Myanmar, China, Vietnam, Cambodia & Thailand, and traversed by its lifeline: the Mekong. To set the scene, I feel that some historical information is required: A former French colony (part of the Indochine 'empire'), now a Marxist-communist nation that is largely Buddhist, it is home to some 6.8 million people, 40% of whom are indigenous hill-tribes, and hence it's ethnic, cultural and architectural diversity is quite striking. French colonial houses, traditional wood dwellings & gilded temples all coexist. Sadly it's also known for being, per capita, the worlds most heavily bombed nation: I was shocked to learn between 1964-74 during the Vietnam war the US dropped 2million tonnes of ordinance on Laos (equal to a plane-load of bombs every 8mins, 24hrs/day, for 9years).
10 November 2015
The excitement I felt on my arrival in Laos was only temporarily reduced by my luggage going missing en route. The slight panic that this type of mishap usually provokes was heightened by the fact that within my suitcase was $2000 worth of much needed medical items that my wonderful friends and family helped me crowd-fund for donation to the hospital. Thankfully it was only day or two later that my suitcase arrived intact, and all the supplies (stethoscopes, paediatric IV Dressings, Broselow tapes and a few toys) were received with great joy by the wonderful team at Lao Friends Hospital for Children 💕 so a massive Thankyou to all of you who donated to the appeal a few months ago!