The State of Vaccine Confidence

The State of Vaccine Confidence

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Confidence Commentary: Blog archive

The limits of predictions: When no one listens

Heidi Larson | September 7, 2015

Two children infected with polio in Ukraine, first cases in Europe in five years, and first cases in Ukraine in over two decades.

 In October of 2014, the Global Polio Eradication’s International Monitoring Board (IMB) issued a warning about Ukraine’s high risk of polio:

“The risk in Ukraine is of deep concern. The last thing the global polio eradication programme now needs is the re-emergence of polio in a place distant from its two epicentres and threatening to reverse the certified polio-free status of a whole region (in this case Europe). Ukraine represents the perfect storm – extreme vaccine shortages, a growing pool of susceptible children, already-weak surveillance disintegrating, armed conflict in the eastern region, and a government seemingly deaf to warnings.

“The situation in Ukraine is particularly dire. The IMB received good information that there are essentially no vaccines at all (for anything, not just polio) in the entire country. There is a strong antivaccination sentiment in the population… There are even rumours that cases of acute flaccid paralysis are being covered up. This creates the perfect storm…”

The IMB was right. The problem is that there was no local action in response to the risk alarm bell. Instead of building up resilience to a known risk, the country let its guard down even more, allowing two children to become paralysed for life by the nearly eradicated (but not there yet) poliovirus. Polio immunisation coverage was already low at barely 50% in 2014, but dropped to 14% in 2015.

On August 28th it was confirmed that one four-year-old and one 10 month old child had been paralysed by the poliovirus in the south-western part of the Ukraine, on the borders of Hungary, Poland, Romania, and Slovakia. In this case, the virus was not (yet) carried by one of the thousands of refugees moving across Europe, which has seriously worsened since the risk was warned by a November 2013 correspondence in the Lancet, but instead transmitted via  a vaccine-derived strain from the oral polio vaccine (OPV). Circulating vaccine derived polio virus (cVDPV) infection is not directly transmitted from an OPV vaccination, but, in rare circumstances — particularly where vaccination coverage is very low, the live attenuated virus can be shed in the environment by those vaccinated and mutate to become strong enough to act like the wild polio virus (WPV). The only way to stop cVDPV transmission is the same way as stopping the spread of wild polio virus – intensive vaccination.

While, in principle, adequate supplementary immunisation campaigns could contain the further spread of polio, it will mean not only an adequate vaccine supply and prompt government response, but a public willing to comply with rounds of polio vaccination.

“Ay, there’s the rub” as Hamlet proclaimed. The “rub” – originally referring to a rough spot in a bowling surface or golf green that risks throwing the game off course – is, in this case, historic broken public trust following a confidence crisis in 2008 when a 17-year old died following an MR vaccination in a measles and rubella campaign which was followed by nearly 100 people, mostly children, hospitalised with vaccine concerns due to reported headaches, fevers and other symptoms. The then president, Viktor Yushchenko, called off the vaccination campaign while the cases were being investigated, but public confidence has remained weak, fuelled by various other triggers of distrust.

The impact of the 2008 broken trust extended to multiple vaccines as reported in the latest Ukraine immunisation update. Most vaccines, including polio, show a significant drop in coverage between 2008 and 2010, with slow progress on recovering to pre-2008 acceptance.

The current call for urgent polio vaccination rounds in the Ukraine will only succeed if the “rub” of persisting low-to-no confidence in vaccination is somehow addressed.

The risk of spread to other European countries depends on their level of vaccination protection. According to the Risk Assessment recently issued by the European Centre for Disease Control (ECDC), overall Europe is at low risk of polio transmission, but ECDC concludes that Bosnia and Herzegovina, Romania and Ukraine are at high risk for further polio spread.

But, this is just the beginning of a tale about to unfold as the waves of mass migration come to Europe for refuge.