Drop in immunisation rates hits vaccine-maker's revenue

A fall in immunisation rates has affected revenue for CSL's flu vaccine-making business. (Sam Mooy/AAP PHOTOS)

Revenue from CSL's flu vaccine-making business dropped sharply in the first half of the financial year amid a significant fall in immunisation rates, particularly in the US.

CSL Seqirus brought in revenue of $US1.66 billion ($2.6 billion) in the six months to December 31, down nine per cent from a year ago.