All of following are true about measles except-

<p>MEASLES:- An acute highly infectious disease of childhood caused by a specific virus of group myxovirus. Clinically characterised by fever and catarrhal symptoms of the upper respiratory tract( coryza,cough), followed by a typical rash. Incubation period-10 days from exposure to onset of fever and 14 days of appearance of rash. Secondary attack rate-infection confers life long immunity as there is only one antigenic type. Vaccine- live attenuated subcutaneous vaccine. Age-before 9 months.The age can be lowered to 6 months if there is measles outbreak in community.For infants immunised between 6 and 9 months,second dose administered as soon as possible after the child reaches 9 months provided that at least 4 weeks have elapsed since the last dose. Route-subcutaneous/intramuscular. {Reference: park&;s textbook of preventive and social medicine, 23rd edition, pg no.149}</p>