A vaccine-resistant polio strain discovered

November 5, 2014, Institut de Recherche pour le Développement (IRD)
Poliovirus. Credit: Institut Pasteur / C. Dauguet

The global initiative to eradicate poliomyelitis through routine vaccination has helped reduce the number of cases by more than 99% in 30 years, from an estimated 350,000 cases in 1988 to 650 reported cases in 2011. However, major epidemics are still occurring today, such as the ones in the Republic of the Congo in 2010, Tajikistan in 2010, and China in 2011. The epidemic outbreak in 2010 in the Republic of the Congo differed from the others in its exceptionally high mortality rate of 47%: out of the 445 confirmed cases, nearly 210 died. The researchers first attributed the seriousness of the epidemic to low vaccine coverage.

Newly identified mutations of the virus

In reality, the cause was something completely different. An international team including IRD researchers has just identified the virus responsible and sequenced its DNA. The DNA sequence shows two mutations, unknown until now, of the proteins that form the "shell" (capsid) of the virus. On the face of it, this evolution complicates the task for the antibodies produced by the immune system of the vaccinated patient as they can no longer recognise the viral strain.

The researchers then tested the resistance of this variant of poliovirus on blood samples from more than 60 vaccinated people, including volunteers living in neighbouring Gabon, where part of the research team was based, and German medical students. Their antibodies were shown to be less effective against the Congo strain than against the other strains of poliovirus. The researchers estimate that 15%–30% of these people would not have been protected during the 2010 epidemic.

At a time when the global campaign to eradicate is entering its final phase, researchers fear that other variants of the virus may emerge among populations immunised with the vaccine. Undoubtedly, these strains are circulating in nature. While quite rare, they could lead to fatal such as the one in 2010 in the Republic of the Congo if they reach areas where the more common strains have been eradicated, but where is insufficient. The researchers are calling for better clinical and environmental monitoring to completely wipe out the scourge of polio.

Explore further: Mutant poliovirus caused Republic of Congo outbreak in 2010

More information: DREXLER J.F., GRARD G., LUKASHEV A.N., KOZLOVSKAYA L.I., BÖTTCHER S., USLU G., REIMERINK J., GMYL A.P., TATY-TATY R., LEKANA-DOUKI S.E., NKOGHE D., EIS-HÜBINGER A.M., DIEDRICH S., KOOPMANS M., LEROY E.M., DROSTEN C. "Robustness against serum neutralization of a poliovirus type 1 from a lethal epidemic of poliomyelitis in the Republic of Congo in 2010." Proceedings of the National Academy of Sciences, 2014, vol. 111 no. 35, 12889–12894, DOI: 10.1073/pnas.1323502111

GRARD G., DREXLER J. F., LEKANA-DOUKI S., CARON M., LUKASHEV A., NKOGHE D., GONZALEZ JEAN-PAUL, DROSTEN C., LEROY ERIC. "Type 1 wild poliovirus and putative enterovirus 109 in an outbreak of acute flaccid paralysis in Congo," October-November 2010. Eurosurveillance, 2010, 15 (47), p. 6-8. ISSN 1560-7917 fdi:010052948

Related Stories

Mutant poliovirus caused Republic of Congo outbreak in 2010

August 19, 2014
(Medical Xpress)—In 2010, a polio outbreak in the Republic of Congo (ROC) resulted in 445 confirmed cases, of which 47% were fatal. Originally, researchers thought low levels of immunization were responsible for the severity ...

WHO revises Ebola toll

November 1, 2014
The World Health Organization Friday revised its figures showing more people killed by the deadly Ebola virus, but the number of cases of the disease was slightly lower.

New step towards eradication of H5N1 bird flu

October 31, 2014
A University of Adelaide-led project has developed a new test that can distinguish between birds that have been vaccinated against the H5N1 strain of avian influenza virus or "bird flu" with those that have been naturally ...

DR Congo Ebola outbreak has killed 42 since August: govt

October 1, 2014
The Democratic Republic of Congo raised its death toll from the dealy Ebola virus to 42 on Wednesday as it struggled to contain the second outbreak of the deadly disease in Africa this year.

Ebola virus in Africa outbreak is a new strain

April 16, 2014
The Ebola virus that has killed scores of people in Guinea this year is a new strain—evidence that the disease did not spread there from outbreaks in some other African nations, scientists report.

Ebola kills 2,300, nearly half of deaths in past 21 days: WHO

September 9, 2014
The Ebola epidemic in west Africa has claimed nearly 2,300 lives, the World Health Organization said Tuesday, stressing that nearly half had died in less than a month.

Recommended for you

Researchers find infectious prions throughout eyes of patients with deadly sporadic Creutzfeldt-Jakob disease

November 20, 2018
By the time symptoms of sporadic Creutzfeldt-Jakob disease (sCJD) are typically discovered, death is looming and inevitable. But, in a new study, researchers at University of California San Diego School of Medicine with colleagues ...

Researchers a step closer to understanding how deadly bird flu virus takes hold in humans

November 19, 2018
New research has taken a step towards understanding how highly pathogenic influenza viruses such as deadly bird flu infect humans.

Infants born to obese mothers risk developing liver disease, obesity

November 16, 2018
Infant gut microbes altered by their mother's obesity can cause inflammation and other major changes within the baby, increasing the risk of obesity and non-alcoholic fatty liver disease later in life, according to researchers ...

New study shows NKT cell subsets play a large role in the advancement of NAFLD

November 16, 2018
Since 2015 it has been known that the gut microbiota could have a direct impact on nonalcoholic fatty liver disease (NAFLD), which affects up to 12% of adults and is a leading cause of chronic liver disease. In the November ...

Antibiotic prescribing influenced by team dynamics within hospitals

November 15, 2018
Antibiotic prescribing by doctors is influenced by team dynamics and cultures within hospitals.

Discovery suggests new route to fight infection, disease

November 14, 2018
New research reveals how a single protein interferes with the immune system when exposed to the bacterium that causes Legionnaires' disease, findings that could have broad implications for development of medicines to fight ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.