School of Population Health

Eradication of polio – Is Syria being left behind?

A child receiving polio vaccine

Mohana Kunasekaran

16 May 2017

Eradication of polio – Is Syria being left behind?

Since 2013, after a 14 year absence and more than six years after the Syrian civil war began, another hostile threat has been emerging in the conflict zone. 

“We thought it was the flu or just one of those fevers she gets all the time. We kept going to the doctors and the pharmacy and tried different things. We gave her a shot in her right leg because she was not able to stand”, an example of a typical response a Syrian mother would give in an interviews. Her child would be one of many children confirmed to have the crippling circulating vaccine-derived polio virus (cVDPV). In 2017, for the first time VDPV cases have outnumbered the number children paralysed by wild-type polio (WPV) (Figure  1.) and this trend is expected to increase.

Figure 1: Total number of cases in the world by year

image - Eradication of polio – Is Syria being left behind?

Note: For 2007 to 2016 the duration of surveillance was from 1 Jan to 31 Dec of the year, for 2017 the duration of surveillance was till 27 June 2017, Data used from Reference (1,2).

One of the reasons VDPV occurs is there are sufficiently large numbers of unimmunised children to allow for circulation of the virus, in addition to those with weakened immune systems. Poor sanitation allows the virus to remain in circulation for a longer period of time, thus creating more opportunities for mutations with increased virulence. To be clear, someone cannot get VDPV by just receiving the oral polio vaccine (OPV) as anti-vaccination activists or members of the regime would like people to believe. WPV and VDPV are similar to one another but researchers have shown that the weakened live virus strain of the vaccine replicates inside the child’s gut over a period of one to two months after vaccination, gets excreted into the waterways, may mutate, where factors such poor sanitation and hygiene results in another child taking in this strain and the vicious cycle perpetuates (3). Three mutant strains have appeared in this way and it seems that the very tool that was used effectively for about three decades resulting in the elimination of WPV2 is slowly revealing itself to be a ‘Trojan’ horse that humanity unknowingly gave itself in this long draw out battle against polio (4).

In the war against polio in Syria, some of their more compassionate neighbours have stockpiled OPV and enlisted local councils and doctors in rebel held areas to train small army of volunteers for an unprecedented door-to-door campaign, navigating through a mine field of rebel militias and attacks from all fronts as the regime considers those working part of the polio vaccination campaign as enemies of the state (5,6). Attacks ranging from kidnappings, shootings and bombings targeting polio workers, vaccination centres and law enforcement personnel guarding polio workers are prevalent in Syria and neighbouring countries such as Pakistan in recent years (7,8). There is no guarantee these men would get to the front door of an unimmunised child in Deir Ezzor, the governate with the most number of polio cases and the highest rates of parent refusal. If they by some miracle get there, there is another hurdle waiting: parents who refuse to vaccinate their children either for legitimate fear for being seen as siding with those is against the regime, or residual fears stemming from a 2014 measles vaccine mix up which led to the tragic death of 17 children (9, 10, 11).

It seems that while Syria is fighting its own war on a few fronts, the rest of the world has decided to adopt a more peaceful approach towards the ‘Trojan’ horse by switching to the inactivated polio vaccine (IPV). It seems that the biggest challenge to this strategy was to gain buy in from cynical policy makers and healthcare workers, to coordinate the switch from the OPV to the inactivated IPV in stages (12). It does seem that the main risk to those administrating this would be paper-cuts and dry watery eyes from trawling through long email threads.  In 2016, 155 countries switched from using the trivalent OPV to bivalent OPV in a synchronised way, the initial steps in what the rest of the world hopes would be the decisive round against polio (13, 14).

However, for Syria and for the parents there, being left behind may not necessarily be a terrible thing. The reasons for sticking to the OPV, although soon considered to be antiquated are still valid. Firstly, they are cheap, costing about 10-12 cents a dose compared to about $3 per dose for the injectable (15). Secondly, it can be administered orally as drops by anyone while the IPV needs to be injected by a trained health professional. Thirdly and most importantly, there is insufficient IPV available and manufacturers do not have the resources to produce the necessary quantities needed to change to the IPV, especially in the current outbreak situation (16,17). The IPV may not be able to rise to the occasion and deal the final blow, as those immunised with IPV can still carry and spread the virus. Although history reveals that the Greek forces hidden in the ‘Trojan’ horse crept out in the cover of night and destroyed the city of Troy after a decade-long stalemated siege, ending the war, one can only hope that we would avoid a repeat of such a tragedy. Hopefully, we have been alerted in time and there is still the opportunity and possibility to seal the ‘Trojan’ horse in Syria if the volunteer vaccinator army just manages to knock on enough doors and put a few drops of OPV in sufficient number of children.


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