My child still has a body temperature of 98.9- 99.5 on the 3rd day of an antibiotic course for his chest infection. is the antibiotic working?

Antibiotic: Not antipyretic, antibiotics are for treating infection not to reduce fever, your child has a low grade fever, he might be responding to the antibiotic and infection is being cleared hence the reduction oin fever, or he has had a viral infection from the start, and also abating, just observe for improved general condition, if not, see the doctor for re-evaluation