Lombardy Region, with the Deliberation NoVIII (22-12-2005), about vaccinations in childrens and adults, suggest to offer to the healthcare workers (HCW) of 'Infectious diseases' and of 'Obstetrics and 'Pediatrics' Department, the vaccines for varicella and measles, mumps and rubella (MMR). We performed in 120 HCW of our hospital the dosage of antibodies versus these infectious diseases, in order to protect both workers and critical patients. The study results show that more than 80% of the HCW was immune to all the four infectious diseases. The percentage of immunisation to measles, varicella and rubella exceeded the 90%, while 87.5% of HCW was immune to mumps. We are going to offer the vaccine to the operators that are not immune, but we are also thinking about offer it to the HCW working with critical patient.