15,000 Romans had fallen, and as many were captured; in other words, the army was annihilated.

The slight Carthaginian loss--1500 men--again fell mainly upon the Gauls.( 3) And, as if this were not enough, immediately after the battle on the Trasimene lake, the cavalry of the army of Ariminum under Gaius Centenius, 4000 strong, which Gnaeus Servilius had sent forward for the temporary support of his colleague while he himself advanced by slow marches, was likewise surrounded by the Phoenician army, and partly slain, partly made prisoners.

All Etruria was lost, and Hannibal might without hindrance march on Rome.
The Romans prepared themselves for the worst; they broke down the bridges over the Tiber, and nominated Quintus Fabius Maximus dictator to repair the walls and conduct the defence, for which an army of reserve was formed.

At the same time two new legions were summoned under arms in the room of those annihilated, and the fleet, which might become of importance in the event of a siege, was put in order.
Hannibal on the East Coast Reorganization of the Carthaginian Army But Hannibal was more farsighted than king Pyrrhus.

He did not march on Rome; nor even against Gnaeus Servilius, an able general, who had with the help of the fortresses on the northern road preserved his army hitherto uninjured, and would perhaps have kept his antagonist at bay.