id	keyword
hls-1978	polio
hls-1978	opv
hls-1978	ipv
hls-1978	vaccine
hls-1978	eradication
hls-1978	india
hls-1978	poliovirus
hls-1978	countries
hls-1978	use
hls-1978	wpv
hls-1978	doses
hls-1978	poliomyelitis
hls-1978	immunization