User:BJeffrey/The end's in sight

Poliomyelitis: The end's in sight

Poliovirus has already been largely eradicated worldwide. However there are still three countries in which Polio is still endemic: Nigeria, Afghanistan and Pakistan. Whilst Polio remains endemic in these countries it is still a major global threat to public health.

Until 2011 Polio was also still endemic in India but a huge, nationwide vaccination program has successfully eradicated Polio from India and this gives us great hope that, with lessons learnt from India and the £1 billion grant, we can finally eradicate Polio worldwide.

Epidemiology

Polio is a disease caused by the positive sense, RNA virus-Poliovirus. It is transmitted through the faecal-oral route and proliferates within the pharynx and gastrointestinal tract where it incubates for typically 7-14 days. 95% of infections with Poliovirus are entirely asymptomatic, approximately 4% of infections result in Abortive Poliomyelitis, which cause fever, sore throat and gastroenteritis. Patients with Abortive Polio normally recover within about a week. The final 1% of infections result in the most severe form of the disease: Paralytic Polio. There are three forms of Paralytic Polio; Spinal Polio (the most common), which causes asymmetric paralysis of the lower extremities; Bulbar Polio, which causes weakness in muscles controlled by cranial nerves; and Bulbospinal Polio, which has symptoms of both Spinal Polio and Bulbar Polio.

There are three different serotypes of Poliovirus named type 1,2, and 3 but only types 1 and 3 are still circulating in the wild. Currently there are five different vaccines in use. Four of the five are orally administered live attenuated vaccines; these are a trivalent form which targets all three serotypes, two monovalent forms which target type 1 and 3 respectively and a bivalent form which targets both type 1 and 3. The final vaccine in use is an inactivated, intravenous vaccine which provides immunity against all three serotypes. It was necessary to create an inactivated vaccine due to the risk of reversion from attenuated forms to pathogenic forms of the virus in the live attenuated vaccines which can cause symptoms of Polio. Live attenuated vaccines are still in use however cause they are far cheaper than the alternative and do not have to be refrigerated in transit.

Since the introduction of the Global Polio Eradication Programme in 1988, the global distribution of Polio has greatly decreased. There are now only three countries in the world (Nigeria, Afghanistan and Pakistan) in which Polio is endemic (meaning the virus can sustain itself within the population without external input). This is a huge improvement from the state of affairs in 1988 when Polio was endemic across 125 countries including all of Africa and Asia and several countries in Europe, Australasia and South and Central America.

Global burden of disease

Currently the global burden of Polio is a lot less than it has been in the past. Between the beginning of January and the end of May 2013 there have 34 reported cases with 22 in Nigeria, 2 in Afghanistan, 8 in Pakistan, 1 in Somalia and 1 in Kenya. The cases in Somalia and Kenya represent recent outbreaks as a result of the disease spreading from endemic countries (most likely Nigeria).

The actual number of cases of infection is probably much higher than this however as most infections do not result in any pathology and therefore will not be recorded by the health authorities.

Current funding situation

The Global Polio Eradication Initiative (GPEI) predicts that under their current strategy Polio will be eradicated by 2018 costing $5.5 billion which is approximately £3.6 billion. This funding is largely provided by national governments and charitable organisations such as Rotary International and the Bill & Melinda Gates Foundation. However, even with funding being provided from a wide range of organisations and governments there is still a funding gap estimated to be around $660 million (£435 million) for 2013.

The end's in sight

Background

Since 1988 and the beginning of the global initiative to eradicate Polio the global distribution and burden of Polio has seen a massive decline. The strategic use of the vaccines and accompanied public information to encourage people to accept it has clearly been a great success. The most recent success in the drive to eradicate Polio has been its complete eradication from India which used to record hundreds of cases Polio a year as recently as the early 2000's.

Justification

Despite the incredible achievements that have already been made in the attempt to rid the world of Polio there is still more effort required to make this mission complete and ensure that Polio never makes a resurgence in countries from which it has been eradicated. Whilst there are still countries that are endemic for Polio a resurgence will always be a risk and this is demonstrated by recent outbreaks in Somalia and Kenya. For this reason we believe that the implementation of our scheme based on a £1 billion budget is vital as a public health initiative.

Proposal

Our proposal is to split our £1 billion budget equally between the two remaining centres of Polio endemicity; Nigeria and Afghanistan/Pakistan.

The main issue faced by initiatives to eradicate Polio in the remaining endemic countries has not been a lack of effective vaccines but a mistrust of vaccines and those who supply them. Therefore one of the main focuses of our scheme (particularly in Nigeria where this is a major obstacle to Polio eradication) is gaining public trust through advertisement, and trying to educate grass-roots community leaders such as local politicians and religious leaders.

The other novel concept which distinguishes our project from a straightforward vaccination program is a coordinated effort in tracking the movement of the virus so outbreaks can be pre-empted with vaccination programs. This will be done using GPS and sampling sewage for presence of the virus to detect its presence before a major outbreak begins in a region. This method of tracking the virus' movement was used in India to great effect.

These two concepts, which underpin our proposal, will be used concert with vaccine distribution that will be focused in large nationwide vaccination programs in all three endemic countries. Again this takes inspiration from the Indian Polio eradication program when huge swathes of the population were vaccinated in two separate days.

Goals

Should this proposal acquire its budgeted £1 billion funding, we aim to eradicate Polio worldwide by the end of 2017. This target will be met by working closely with the GPEI to achieve our shared goal and we will therefore accelerate the progress that they have made already.

References

Jorba et al, Calibration of Multiple Poliovirus Molecular Clocks Covering an Extended Evolutionary Range, Journal of Virology, May 2008, p. 4429–4440

Thompson KM, Duintjer Tebbens RJ. Eradication versus control for poliomyelitis: An economic analysis. Lancet 2007;369(9570):1363-1371

Radboud J. et. al, Economic analysis of the global polio eradication initiative, Vaccine, Volume 29, Issue 2, 2010, Pages 334–343

Fine, Herd Immunity : History, Theory, Practice, Epidemiology Review, 1993, 15(2): 265-302

http://www.polioeradication.org/

http://polioinfo.org/

http://www.who.int/en/

http://www.endpolio.org/