All of the following statements are true regarding poliovirus except -
Poliovirus strains are classified into 3 types-1,2 and 3. TYPE 1 most common. REF:ANANTHANARAYAN AND PANIKER'S TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO:486
It is transmitted by feco-oral route
Asymptomatic infections are common in children
There is a single serotype causing infection
Live attenuated vaccine produces herd immunity
Virology