Recent research reports published by The Lancet could make a lot of people rethink the assumption that once a disease has been declared eradicated, that’s it. Done.
A recent resurge in cases of polio in several countries and concern in Europe that antibiotic resistance is being bought there by refugees and migrants are becoming global health issues. The reasons for how these possible setbacks are happening in these two situations differ.
In the case of polio, while illness caused by a “wild” virus — still unchecked among unvaccinated children and others — continues its steep decline, a team of researchers has found that what it calls a “weakened” virus, derived from oral vaccines, can be transmitted inadvertently into communities. Injectable vaccinations could aid eradication, but this is a more expensive way to administer the vaccine.
Sharmila Devi, writing in The Lancet in July, explains the transmission of a weakened virus and why it affects poor communities:
“The oral vaccine contains a live but weakened virus that replicates in the intestine for a short time while producing an immune response,” she wrote. “During that period, the virus is excreted and, in areas of poor sanitation, it can spread in the local community. In areas where vaccination coverage is low, the excreted virus can circulate for longer time, undergo genetic changes, and in less than one in 17 million cases the virus can develop into a form that can cause paralysis.”
Those cases seem like long odds, but experts are nevertheless worried about rare mutant strains derived from weakened oral vaccines appearing recently in the Democratic Republic of the Congo and Papua New Guinea. So far, the vaccine-derived poliovirus outbreaks in 21 countries since 2000 have resulted in fewer than 760 cases of polio, experts at the World Health Organization have concluded. But poverty has often made this situation possible since cases tend to be clustered.
On the good-news side, “wild” polio virus cases (not derived from weakened oral vaccines) are still endemic in only three countries: Afghanistan, Nigeria and Pakistan. Globally, more than 10 billion doses of the oral vaccine have been given to almost 3 billion children since 2000, according to the World Health Organization. More than 13 million cases of polio may have been prevented, Devi wrote in her report on the polio survey.
As for the rise in antimicrobial resistance in Europe, a team of researchers has produced a detailed, technical study based on more than 2,000 reports on 2,319 antibiotic-resistant migrants.
The study, which is available on open access, concluded:
“Migrants are exposed to conditions favoring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries.” Resistance extends to every major class of antibiotic, the authors add.
The research paper stresses that “antibiotic surveillance need[s] to be integrated in all aspects of health care, which should be accessible for all migrant groups,” even after migrants have been settled in host countries.
“More than 30 million European Union (EU) residents are born outside the EU and more than 2 million migrants have entered Europe since 2015 during the recent refugee crisis,” the authors wrote. “Whether migrants — and refugees and asylum-seekers in particular — have high rates of AMR antimicrobial resistance or infection . . . remains unknown.”
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