Researchers from the World Health Organization (WHO), US Centers for Disease Control and Prevention (CDC) and Imperial College London conducted a clinical study in India on 954 children aged 6 months to 10 year. These participants were already vaccinated with the vaccine oral poliomyelitis (IPV). They received either an injection of Salk, another dose of oral polio vaccine or no booster.
The scientists evaluated the dosage of the disease in the stool at 3, 7 and 14 days.
Poliomyelitis is a viral infection caused by poliovirus, which can lead to paralysis and death. It mainly affects children under 5 years old. The virus is transmitted through food and water contaminated with the virus and multiplies in the intestine. It can then invade the nervous system, causing paralysis in one out of 200 cases.
The combination of the two vaccines to eliminate the disease
The results of the trial reveal that for all age groups, booster injections with Salk reduce the concentration of poliovirus type 1 or 3 in the stool.
“These clinical trials have revolutionized our understanding of IPV and how it can be used in our global polio eradication efforts by ensuring that children have the best and fastest protection against this disease,” says Bruce Aylward, Deputy Director General for Polio of the World Health Organization.
“The two vaccines complement each other and should be used to break the last chains of transmission of the virus and achieve a polio-free world more quickly,” insists Roland Sutter, research coordinator at WHO.
80% of the planet is now officially free of the poliomyelitis virus. But the disease is still endemic in Afghanistan, Nigeria and Pakistan, according to WHO figures.
In 1998, 350,000 polio cases were recorded. In 2012, the number of cases fell to 223. But last year there was a sharp increase in polio cases with 406 new infections. An increase mainly due to the interruption of vaccination campaigns in conflict regions. This is how in Syria, 25 cases of polio were recorded in March 2014 while the virus had disappeared from the country since 1999.
