Does the lack of improvement mean that the antibiotic is poorly chosen or do you still have to wait for the effects?

There is a possibility that the antibiotic does not work if the bacterial infection was caused by a pathogen resistant to cefaclor (the active ingredient in Ceclor) or if it is viral in nature, since viruses are not sensitive to antibiotics. The speed of action of the antibiotic and the occurrence of improvement also depends on its type. In the case of bactericidal antibiotics, the effect is usually rapid, and improvement can occur after a day of treatment, bacteriostatic antibiotics may act a little slower. Cephalosporins such as cefaclor have a bactericidal effect because they inhibit the synthesis of the bacterial cell wall. Similarly, however, in the case of a large outbreak or increased infection, the drug needs more time to significantly reduce the amount of bacteria. The general rule is that if after 2-3 days of taking the antibiotic there is no improvement in health, or even worsening, then you should consider changing the therapy after contacting a doctor. I enclose additional information: https://www.gdziepolek.pl/artykuly/fakty-i-mity-o-antybiotykach https://www.gdziepolek.pl/kategorie/bol-i-goraczka-u-dziecka