End Polio Now Position - 16th October 2018

Don’t forget polio – the polio viruses have not forgotten us.

Rotary International is committed to continue the eradication of polio campaign until the WHO declares polio is eradicated. By this it means the interruption of the transmission of polio viruses for at least three years, in the presence of certified surveillance and when all polio virus stocks have been contained.

Global position:

  WPV1 cVDPV
2018 to 16 October 2018
20 68
2017 to 17 October 2017 12 61
2017 full year
22 96
2016 full year
37 5
2015 full year 74 32
2014 full year 359 56

 The emphasis now is on:

  • Monitoring the date of the most recent onset of paralysis and the number of weeks elapsed.
  • The most recent positive environmental samples and the immunisation response.

Wild Polio virus: 20 cases in 2018

For polio-free certification purposes the start date for WPV monitoring is that of the onset of paralysis.

WPV1 - 20 cases in 2018.

One case in Afghanistan this week.

The most recent WPV1 cases in each country were:

  • In Afghanistan – 1 September 2018 – 6 weeks since the onset of polio.
    • 16 cases in 2018 vs. 7 cases at the same time in 2017. Total of 14 cases in 2017.
  • In Pakistan – 1 August 2018 – 10 weeks since the onset of polio.
    • 4 cases in 2018 vs. 5 cases at the same time in 2017. Total 8 cases in 2017.
  • In Nigeria – 21 August 2016 – 112 weeks since the onset of polio.
    • No cases in 2018. No cases in 2017. Four cases in 2016.

WPV2

  • Declared eradicated September 2015. (Last case was in October 1999.)

WPV3

  • No cases reported since 10 November 2012. (That was in Nigeria.)

There were also 7 WPV1 positive environmental samples collected this week, 2 in Pakistan and 5 in Afghanistan.

Circulating Vaccine Derived Polio Virus - 68 cases in 2018

The virus is genetically changed from the weakened virus contained in OPV. Details of the most recent cases in each country are:

cVDPV1 - 18 cases

  • 18 cases in PNG. Three cases this week.

  • Onset of paralysis of the most recent case - 6 September - 5 weeks ago.

Two cVDPV1 positive environmental samples were collected this week.

 cVDPV2 - 43 cases

4 cases this week. 3 cases in Niger, one case in Somalia.

  • In Nigeria: 16 cases in 2018, no cases this week.
    • Onset of paralysis 11 September 2018 – 5 weeks ago
  • In the DRC: 15 cases in 2018 vs. 9 cases at the same time and 22 cases total.
    • Most recent case – 5 August 2018 – 10 weeks since the onset of polio.
    • Immunisation in neighbouring countries is being strengthened.
  • In Somalia: 6 cases in 2018, one case this week. No cases in 2017.
    • Most recent onset of paralysis 2 September 2018 - 6 weeks ago.
  • In Niger: 6 cases, 3 cases reported this week.No cases in 2017.
    • Most recent onset of paralysis 7 September 2018 - 5 weeks ago.
  • In Syria: 0 cases in 2018
    • 74 cases in 2017. Arose after discovery of pockets of infection after the defeat of ISIS. There have been no cases since the outbreak last year.
    • Most recent case 21 September 2017 – or 55 weeks since the onset of polio.

Confirmation of cVDPV2 positive environmental samples in Kenya have not isolated the virus from any AFP cases or their contacts.

cVDPV3 - 7 cases

  • In Somalia: 7 cases. One new case this week.
    • Onset of paralysis for the most recent case was 7 September – 5 weeks ago. The first cases since July 2013 when there was one in the Yemen.

 

Other comments (from the internet and other sources):

Polio: Environmental monitoring will be key as world reaches global eradication.
(University of Mitchigan, Ann Arbour)

Robust environmental monitoring should be used as the world approaches global eradication of polio, say researchers who recently studied the epidemiology of the 2013 silent polio outbreak in Rahat, Israel. Israel's strong environmental surveillance program detected the epidemic and allowed for rapid mobilization of a vaccine before any cases of acute flaccid paralysis occurred.  Nevertheless, the researchers found that a substantial proportion of children under 10 were likely infected over the course of the outbreak. Because these infections did not result in paralysis, this type of outbreak is termed 'silent'--silent transmission is of concern because it can lead to paralytic cases if left undetected and uncontrolled.

Even as we are at the brink of polio eradication, silent transmission of wild-type and vaccine-derived polioviruses are expected to continue sporadically, the researchers say. "Environmental surveillance is particularly useful for detecting silent circulation of the disease," said first author Andrew Brouwer, a research investigator in epidemiology at the U-M School of Public Health. "Because paralytic polio only occurs in a small fraction of infections, and that fraction is shrinking as vaccination improves, standard surveillance of paralytic cases will not be sensitive enough to trigger the fast and robust responses needed." To look into the case, Brouwer and colleagues developed an analytical method to estimate the epidemic trajectories from sewage data. "Beyond polio, environmental surveillance of pathogens coupled with our method to estimate epidemic curves is a powerful public health surveillance tool to improve our control of infectious diseases," Brouwer said.

 

Polio eradication target at risk as new cases recorded in Africa

Experts have warned that the eradication of polio is at risk because of continued outbreaks of the disease caused by the vaccine-derived virus. The eradication of wild poliovirus is tantalisingly close - with just 19 cases of the disease so far this year in just two countries, Afghanistan and Pakistan. However, while the numbers of wild polio are falling dramatically, there have been 61 cases of polio caused by vaccine-derived poliovirus this year. VDPV occurs where there is poor sanitation and low levels of vaccination coverage. When a child is vaccinated the vaccine-virus replicates in the gut, generating an immune response. The vaccine is then excreted and very rarely can mutate and spread to other children, especially where vaccination coverage is low. So far this year there have been 61 cases of polio caused by VDPV in Nigeria, 15 in both the DRC and PNG, 12 in Somalia and three in Niger - all countries with poor infrastructure and whose ability to cope with outbreaks is poor. All of these countries - except Nigeria - have been declared as polio-free by the World Health Organization.  “The public perception is that polio is going away but these vaccine-derived outbreaks highlight the importance of continuing to vaccinate,” said. Nick Grassly, professor of infectious disease and vaccine epidemiology at Imperial College, London. But he added: “The first vaccine-derived outbreak was recognised in 2000 and since that time there have been about 30 outbreaks and nearly 1,000 cases. "Now we are getting down to very low numbers of wild poliovirus outbreaks we have to make sure these vaccine-derived outbreaks are controlled.” 2017 was the first year when there were more vaccine-derived cases than wild cases - 96 cases versus 22. In 2016 the Global Polio Eradication Initiative switched from a vaccine containing three serotypes to one containing two serotypes in a bid to combat the spread of vaccine-derived viruses. The “switch”, as it became known, was a success. But while some outbreaks were expected their number and magnitude have been harder to close than anticipated. The switch to the new vaccine means that some children have not been immunised against the serotype two polio. People doing studies in India and Pakistan had been collecting faecal specimens for other reasons, but these specimens could have had polioviruses in them. Surveillance of polio had improved which could also account for the increase in the number of vaccine derived cases.

Pakistan’s polio fighters lend a hand in the battle against measles

Islamabad, October 15, 2018 - More than 31 million Pakistani children are to be vaccinated against measles in late October in a countrywide immunization campaign that pulls together national funding and the polio programme’s greatest asset: its human resources. From 15 to 27 October, Pakistan’s Expanded Programme on Immunization plans to carry out a nationwide measles campaign targeting approximately 31.8 million children aged from nine to 59 months (and six to 83 months in Punjab province). Measles is a highly contagious disease which can be fatal in children, but is preventable with vaccination. The October measles immunization campaign comes as a response to the ongoing measles outbreak in Pakistan. More than 24,000 measles cases were reported in Pakistan in 2017 and, so far this year, there have been 30,000 reported cases. Pakistan typically encounters a measles outbreak every eight to 10 years, and the Federal Ministry of Health, through the EPI, works proactively to stop these outbreaks with regular vaccination campaigns. Although the Polio Eradication Initiative and EPI are separate entities, both work hand in hand on efforts to improve immunization in Pakistan, with the understanding that achieving strong essential coverage is a critical step in bringing Pakistan closer to ending polio, and once this goal is reached, in maintaining polio-free status. During the upcoming national measles campaign, the polio programme will lend its human, physical and systems resources, knowledge and expertise to the task of achieving highest possible immunization coverage against measles across the country. It’s a good fit: many of the areas at highest risk for polio are also at high risk for measles. A key factor in the success of this collaboration is the polio programme’s highly skilled workforce of community vaccinators, frontline health workers and social mobilizers.

During every round of country-wide polio vaccination campaign, around 260,000 frontline health workers work to vaccinate more than 38 million children under the age of five across Pakistan. With vital on-the-ground experience in some of the most challenging settings, they are determined to ensure that the lessons learned in polio are transferred to other health interventions. They understand the dynamics of the population, even as they relate to children, not only at the district level but also at the union council and village level. Unlike the usual polio eradication activities, measles immunization is not done in door-to-door fashion. It is carried out at fixed centers established at health facilities as well as outreach sessions conducted at convenient places within community. Children are mobilized to the vaccination sites where highly trained healthcare professionals administer injectable measles vaccine. Despite these differences, the deep local knowledge which polio workers have developed and the foundation of trust they have built with their communities will prove vital in mobilizing caregivers to take their children for measles immunizations at nearby vaccination sites.

Before the introduction of measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2–3 years and measles caused an estimated 2.6 million deaths each year across the world. During 2000-2016, measles vaccination prevented an estimated 20.4 million deaths globally, making measles vaccine one of the best buys in public health.

 

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.

 

19 October 2018

 

Polio is a highly infectious, crippling and potentially fatal viral disease which mainly affects young children. There is no cure, but there are effective vaccines. The strategy to eradicate polio is based on preventing infection by immunising every child until transmission stops and the world is polio-free. The source of polio virus transmission is infectious humans spread mainly through the faecal-oral route or, less frequently, by a common vehicle (e.g. contaminated water or food) and multiplies in the intestine, from where it can invade the nervous system and can cause paralysis. But, less than 1 in 200 infections leads to this. Of those paralysed, 5% to 10% die when their breathing muscles become immobilised.

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