Author(s): Andrea Trevisan [*] aff1 , Annamaria Nicolli aff1 , Federica Chiara aff1
hepatitis B infection; occupational risk; prevention; protective antibodies; vaccination
HBV infection is a significant biological risk for healthcare workers (HCW), as HCW are exposed to human fluids and consequently to blood-borne pathogens. Prior to the introduction of the vaccination against HBV, the risk of infection was three- to five-times higher in HCW than in the general population, with vaccination and the application of standard precautions contributing to reduce this risk [1 ].
Since 1992, the inclusion of hepatitis B vaccination has been recommended by the WHO in all immunization programs implemented by nations. Indeed, the introduction of HBV vaccination in Europe has markedly reduced the incidence of acute infection.
The introduction of mandatory HBV vaccination in Italy (law 165/1991) has contributed to reducing the incidence of the disease, even in the age group with the highest incidence (15-24 years old), which is largely related to the abuse of parenteral drugs and/or exposure to other risk factors such as unsafe sexual contact [2 ].
The present review intends to highlight the problem of the occupational risk for HCW according to three main items: the prevention of HBV infection (efficacy of vaccination); the protection against HBV infection, discussing both problems related to waning antibodies and those related to nonresponders; and the reduction of occupational risk.
HBV vaccination campaigns using a plasma-derived vaccine began in several countries in the early 1980s. In 1986, a genetically engineered Saccharomyces cerevisiae yeast recombinant vaccine replaced the plasma-derived vaccine. Nationwide intervention reduced new HBV infections and HBV-related mortality within less than two decades, and several countries have achieved a low endemicity status [3,4 ].
Mandatory vaccination was introduced in Italy in 1991, with a vaccination schedule that included 3-month-old children (at 3, 5 and 11 months of age) and 12-year-old adolescents (at time 0 and after 1 and 6 months). This program ensured that the cohorts overlapped 12 years later; the vaccination of adolescents was discontinued in 2003 [4 ]. However, WHO recommends child immunization with a dose within 24 h after birth and second and third doses with an interval of at least 4 weeks, primarily in high-endemicity countries [5 ]. Moreover, the policy of distinct European countries is quite different because the age of vaccine administration is variable. As described in Table 1, some countries vaccinate at birth and others at 2-3 months of age [ 6 ]. There are also differences with regard to the behavior of European countries to declare HBV vaccination as mandatory or only recommended (Table 1) [7 ].
Vaccination against HBV is not mandatory in Italy for HCW, though it is offered for free; this is in contrast to the schedules initially adopted for tetanus vaccination (law 292/63), introduced at first as mandatory for at-risk workers and only later for newborns. This policy has led to a noticeable difference in immunization coverage among HCW born before or after the mandatory introduction of the vaccination [8 ].