NEW DELHI: A study conducted by the Indian Council of Medical Research (ICMR) has revealed that the effect of the vaccine administered to protect children against Japanese Encephalitis (JE) tends to start waning after two years.
It suggests administering a booster dose to all children in endemic regions to protect them against the viral illness. JE, a mosquito borne virus, mostly affects children below 15 years of age. About 25% of affected children die and among survivors about 30%-40% suffer from physical and mental impairment.
In the ICMR study, which has been published in the Journal of Travel Medicine, researchers took blood samples from 266 children aged two to 10 years belonging to one of the JE endemic regions of Uttar Pradesh who had taken two doses of the vaccine and tested them for anti-JE virus-specific antibodies.
Of the 266 samples, tests revealed, 260 (98%) were negative and 6 (2%) were equivocal. The first dose of JE vaccine is usually administered between 9-12 months of age and the second dose administered to children in endemic regions between 16-24 months of age.
In the ICMR study, the 266 children included in the study were sub-divided in five groups; 0-2 years, 2-4 years, 4-6 years, 6-8 years and 8-10 years of age. Tests revealed a decreasing trend of anti-JE virus specific IgG antibody titres across age groups. “The results emphasise the significance of booster doses of vaccine for children living in endemic areas,” the researchers have noted.
In India, during the year 2021, nearly 300 cases of JEV were reported from the states of UP and Assam only. The ICMR scientists say the incidence rate of JE is higher in eastern UP compared with other regions in the state, which may be attributed to the fact that transmission of JE is dependent on agro-climatic factors like the presence of agricultural areas, especially paddy fields. “This region is marked by a characteristic tropical monsoon climate, characterised by humidity and rain in the summers, which are conducive to viral proliferation and JEV dissemination by vectors,” the researchers point out.
It suggests administering a booster dose to all children in endemic regions to protect them against the viral illness. JE, a mosquito borne virus, mostly affects children below 15 years of age. About 25% of affected children die and among survivors about 30%-40% suffer from physical and mental impairment.
In the ICMR study, which has been published in the Journal of Travel Medicine, researchers took blood samples from 266 children aged two to 10 years belonging to one of the JE endemic regions of Uttar Pradesh who had taken two doses of the vaccine and tested them for anti-JE virus-specific antibodies.
Of the 266 samples, tests revealed, 260 (98%) were negative and 6 (2%) were equivocal. The first dose of JE vaccine is usually administered between 9-12 months of age and the second dose administered to children in endemic regions between 16-24 months of age.
In the ICMR study, the 266 children included in the study were sub-divided in five groups; 0-2 years, 2-4 years, 4-6 years, 6-8 years and 8-10 years of age. Tests revealed a decreasing trend of anti-JE virus specific IgG antibody titres across age groups. “The results emphasise the significance of booster doses of vaccine for children living in endemic areas,” the researchers have noted.
In India, during the year 2021, nearly 300 cases of JEV were reported from the states of UP and Assam only. The ICMR scientists say the incidence rate of JE is higher in eastern UP compared with other regions in the state, which may be attributed to the fact that transmission of JE is dependent on agro-climatic factors like the presence of agricultural areas, especially paddy fields. “This region is marked by a characteristic tropical monsoon climate, characterised by humidity and rain in the summers, which are conducive to viral proliferation and JEV dissemination by vectors,” the researchers point out.