Cost-effectiveness of workplace vaccination against measles.

Measles is one of the most contagious infectious diseases. Measles vaccine, which has been introduced in Italy in 1979, is highly effective in preventing the disease (two-dose vaccine effectiveness is 99%). In 2017, Italy was the second country of EU for number of cases of measles. A study conducted in the same year showed that 22.3% of measles infection happened in hospital settings and 6.6% of cases occurred in HCWs. This risk group showed low rates of adhesion to the vaccination campaign. For this reason, we hypothesized that workplace vaccination could lead to better vaccination rates in HCWs. Moreover, we focused the vaccination campaign on a specific target group composed of HCWs not serologically immune and previously not vaccinated. We analyzed the clinical records of measles-specific IgG antibodies of 2,940 HCWs, that underwent occupational health surveillance between 1 January 2017 and 31 December 2017. 15.3% (450) was seronegative for measles, especially in the age group under 35 years. We compared the costs related to strategies with and without serological screening. Our study confirmed that immunization strategy with pre-vaccination screening was cost-effective compared to the vaccination without screening. In our sample, in fact, administration of two dose vaccine only susceptible HCWs determine a saving of 146,262 €. The vaccination of HCWs remains a topical issue in preventing the transmission of infectious disease in the hospital setting. Due to the cost-effectiveness evaluation, we recommend extending the pre-vaccination screening to identify the real susceptible workers.