Highlights and global details:
No new wild polio virus cases have been confirmed this week but four cVDPV2 cases arose in the Democratic Republic of Congo (DRC). Nine WPV1 positive environmental samples were collected worldwide. (Seven samples from Pakistan, one from Afghanistan and the other from the DRC.)
The most recent report of a WPV1 case was on 28 March though the onset of polio was on 21 February. For polio certification purposes the start date will be that of the onset of paralysis.
| WPV | cVDPV | |
| 2017 to 23 May | 5 | 4 |
| 2016 to similar date | 16 | 3 |
| 2016 full year | 37 | 7 |
The most recent WPV1 cases with onset of paralysis were:
• In Afghanistan - 21 February 2017.
• In Pakistan - 13 February 2017.
• In Nigeria - 21 August 2016.
Wild Polio Virus Cases
WPV1 cases:
• 2 cases in Pakistan vs. 11 cases at the same time in 2016. During 2017 over 2,000 cases of infant acute flaccid paralysis tested which is another aspect of how donations to polio eradication are used.
• 3 cases in Afghanistan vs. 5 cases at the same time in 2016.
• No cases in Nigeria. There were no cases in 2015 but cases were identified in 2016 as a result of new initiatives in the northern States where Boko Haram had made access difficult. No new cases since August 2016.
• No other cases though there is much immunisation activity now in the Lake Chad countries following the Nigerian cases in August 2016. Also, from 25 to 28 March, synchronised polio campaigns took place across 13 countries in west and central Africa including Nigeria, Chad, Cameroon, Guinea, Mali and Niger. Over 190,000 vaccinators immunised more than 116 million children over the campaigns.
WPV2 cases:
• Declared eradicated September 2015. (Last case was in October 1999.)
WPV3 cases:
• No cases reported since 10 November 2012. (That was in Nigeria.)
Vaccine derived Polio virus cases
For cVDPV, the corresponding positions for onset of paralysis are:
• cVDPV2 cases in DRC - 18 April 2017.
• cVDPV2 cases in Pakistan - 17 December 2016.
• cVDPV2 cases in Nigeria - 28 October 2016.
• cVDPV1 cases In Laos - 11 January 2016.
cVDPV1 cases:
• Three cases reported in Laos in 2016. In 2015 there were ten cases in Madagascar, eight cases in the Lao Republic and two cases in the Ukraine.
cVDPV2 cases:
• In 2017 two separate outbreaks have occurred, both in the DRC. Four cases in total and the most recent had outbreak of paralysis was 18 April.
The total number of WPV1 positive environmental samples collected in 2017 is 50. The most recent sample was collected on 10 May. (The environmental presence of viral particles lasts for 7-14 days.)
The source of polio virus transmission is infectious humans but only 1 in 200 infections leads to irreversible paralysis. Of those paralysed, 5% to 10% die when their breathing muscles become immobilised.
Other comments (from the internet and other sources):
More on the meningitis work - polio programme staff from across Nigeria joined efforts to combat meningitis in Sokoto, providing support and expertise in outbreak response. Almost 200 WHO polio officers worked with state and national government agencies to plan and implement a state-wide vaccination campaign aimed at reaching almost 800,000 young people at risk of contracting the disease. Meanwhile more than 1,900 health workers and volunteers kick started a mass polio vaccination campaign targeting approximately 332,000 children from conflict affected Mosul and other underserved areas in Ninewa Governorate. The campaign is targeting children residing in 9 districts that include newly accessible areas and 16 internally displaced persons camps. Vaccination teams are making special efforts to reach every child through house-to-house/tent to tent visits. Following the G20 meeting the GPEI Transition Plan has been posted. See: http://polioeradication.org/polio-today/preparing-for-a-polio-free-world/transition-planning/
For more than a year there has been a severe shortage of the injectable polio vaccine. Manufacturers have been racing to overcome production problems but the shortage could be repeated in a few years. The WHO recommends children vaccinated with the injectable product get two doses. Initially there may not be enough to give all children two full doses. In the developing world, where the risk of polio is greater, most children are protected with the much cheaper oral polio vaccine. That vaccine has some risks, however, and will need to be withdrawn from use at a point. For at least a decade after that, countries will be urged to use injectable vaccine — a need that could not be met with existing manufacturing capacity. When polioviruses stop spreading the threat of the disease will not be relegated to the history books. Polioviruses might have gone undetected in hard-to-reach conflict zones. Or an accident at a vaccine plant — like one in Belgium in 2014 that pumped polioviruses into a river and the North Sea — could release the viruses back into the world. Adequate supplies of injectable vaccine will be needed to prevent backsliding. As a result of the shortage, 35 countries have been limited or had no access to injectable vaccine for their children in the lead-up to and in the year after “switch” which occurred in the spring of 2016. The polio program didn’t give manufacturers enough time to ramp up production to meet the increased demand generated by the switch. A lot of effort is now being directed to try to meet the next surge in need when the oral vaccine is withdrawn entirely. If transmission stops in 2017, that means as early as 2021 the world will need more injectable polio vaccine than it can currently make. That’s not a long lead time in the world of vaccine production. Studies are testing whether pairing the vaccine with a performance boosting adjuvant will work. This would allow for vaccine dose stretching. A child could then be protected with less vaccine. Companies are exploring whether there are different ways to grow the viruses used in vaccine production to increase the yield, in effect to make bigger batches with each production run. Another option is one that countries are currently being encouraged to try using smaller doses of the injectable vaccine. Research has shown that two small doses, each the equivalent of one-fifth of a standard shot, are as effective as a full shot, if injected in the skin rather than into a muscle as the vaccine is currently given. But intradermal vaccination requires special needles and the medical staff need to be trained on how to vaccinate this way. Some countries are adopting this approach to stretch vaccines supplies in the current shortage, but it may not be workable in all settings and will take time to implement. The development of newer and better polio vaccines for the post-eradication era is being encouraged. A recent recommendation from the WHO suggests a robust market for polio vaccines should exist for more than a decade after eradication. The Strategic Advisory Committee of Experts on Immunisation recommended that countries continue to vaccinate against polio for at least 10 years after the viruses are declared gone. And countries that have research institutions work, or store polioviruses or production facilities making vaccine from polioviruses are urged to continue to vaccine indefinitely. There is a need for having a safe supply, an adequate supply and ideally, a supply at minimal cost, particularly to developing countries.
Reg Ling
Rotary Club of Chandler's Ford and Itchen Valley.
Rotary District 1110 (Central Southern England and the Channel Islands).
Rotary Zone 18A (Southern England and Gibraltar) End Polio Now Coordinator (EPNC).