At least 79 babies born at the same hospital in Rome have been infected with tuberculosis.
Authorities say screening was ordered after a nurse who worked at the Gemelli Hospital neonatal ward tested positive.
The babies were born between March and July, at the same time the nurse worked there.
Doctor Antonio Alberto Zuppa, a paediatrician at Gemelli Hospital, said: “This nurse is one of those who received a vaccination but, as is already well known, the vaccination against TB is only 50 percent effective.”
A parliamentary health committee has demanded a report from the local authorities, to find out whether correct procedures were followed.
The government maintains there is no need for panic, however. It says millions are exposed to tuberculosis every year but only a few thousand develop full-blown TB.