This post was originally produced for Forbes.
Two cases of polio were reported in Ukraine this week, according to the Global Polio Eradication Initiative, known commonly as the GPEI, weekly surveillance report. Both cases were a result of circulating vaccine derived polio virus. At the same time, the partnership of global organizations fighting to eradicate polio from the planet this year reported no new cases of the wild polio virus were identified anywhere in the world in the past week, despite the fact that it is now the high season for polio–a reason for cautious optimism.
The outbreak in Ukraine arose from vaccinations in country, World Health Organization spokesman Oliver Rosenbauer explained by email, “This strain arose in Ukraine, due to significant vaccination coverage gaps in the country. As many as 50% of children are under- or unimmunized, so there are many susceptible children, and this increases the risk of polio re-emerging or being re-introduced. This further underscores the danger of polio until it is eradicated completely. The best thing countries can do to protect themselves is to maintain high vaccination coverage.”
Europe has been polio free for five years, according to the BBC. Rosenbauer notes, however, that there is relatively little threat of contagion to nearby bordering countries, including Romania, “Countries bordering south-western Ukraine have relatively high vaccination coverage and good disease surveillance. But as mentioned, the possibility cannot be ruled out. The much greater threat is for further spread of this outbreak within Ukraine. Fifty percent of children are underimmunized, this gives the virus a lot of susceptible children to find and the chance to spread further. That’s the real danger at the moment, and that is why it is critical that an urgent outbreak response is implemented as rapidly as possible.”
One of the reasons that this outbreak doesn’t represent a major threat to public health because the circulating vaccine derived polio virus is typically less virulent, Rosenbauer said, “It’s true that this strain is comparatively ‘weaker’ than wild poliovirus. Ie it tends not to spread as easily, it tends not to cause as many cases. Nevertheless, we know that it is strong enough to cause paralysis, and two children are now paralysed by this strain. But in theory it should be easier to stop than a wild poliovirus outbreak.”
Ultimately, however, the threat is dependent on the response, Rosenbauer added, noting that “it all depends on how rapidly and urgently an outbreak response will now be implemented. A full and rapid outbreak response will stop this strain in a matter of a few months. But if the outbreak response is delayed or not fully implemented, then the virus will be allowed to continue to circulate and to continue to cause cases. So all depends on the quality and timeliness of the response. We’ve been very encouraged by the urgent measures the government of Ukraine has been putting in place this week, since finding out about the outbreak. Within 12 hours of receiving news of the outbreak, for example, the Minister of Health went on national TV and announced that the country was affected by a dangerous polio outbreak and of the need to implement urgent outbreak response. This commitment needs to now translate into a high-quality outbreak response.”
The outbreak is also a reminder for Americans opting out of immunizations that until polio is completely eradicated from the globe. Rosenbauer explains, “Diseases such as polio are only a plane-ride away. Polio can easily come back, and it is a virus that is extremely efficient at finding susceptible children. In the mid 1990s, poliovirus travelled all the way from India to find a community in the Netherlands, who had refused vaccinations. More than 70 children were paralysed for life. This is a dangerous disease, it is a painful disease, it causes lifelong paralysis. And there is no reason why any child should be affected by this disease any more. Safe and effective vaccines can easily prevent it.”
Notwithstanding the outbreak in Ukraine, there is reason for optimism in the global fight against polio. In the mid-80s, there were on the order of 350,000 to 400,000 cases per year. In 2014, according to the GPEI, there were 359 cases of polio caused by the wild polio virus, representing a 99.9 percent reduction in the number of cases. On average last year there were about 7 cases per week. So far in 2015, the number of cases is just 37, a pace of barely more than one per week. In Pakistan, the country with the greatest number of cases this year, there have been no confirmed cases since June 30. The most recent case in Afghanistan, where only eight cases have been reported all year, was on August 1, more than a month before yesterday’s data was published.
It is certainly premature to suggest that the August 1 case is the last case of polio from the wild virus, it is clear that the wild polio virus is on the ropes. There is good reason to hope that 2015 will feature the last case of wild polio in history. It will take some years of subsequent vigilance to be certain that the disease is truly eradicated, but 2015 could be a historic year.
Rosenbauer adds, “The job is not nearly finished, that is for sure. And if Ukraine shows us anything, it’s how unforgiving polio is to any area with significant vaccination coverage gaps. So efforts must be redoubled everywhere.”
The Global Polio Eradication Initiative is led by Rotary International and includes the US Centers for Disease Control, the World Health Organization, UNICEF and the Bill and Melinda Gates Foundation.