As a result of multiple types of potential exposures to microbial pathogens transmitted via bloodborne, airborne and direct contact mechanisms, healthcare workers (HCW), including dental staff, have been documented to have particular occupational risks for a number of vaccine-preventable diseases. Over the years, public health agencies and professional health organizations have monitored the incidence of occupational infections and developed recommendations for HCW vaccinations, where appropriate.

Initially, these guidelines primarily were aimed at stimulating immune protection for those HCW who had compromised immune defenses that could reduce their ability to resist and/or recover from certain infections. The rationale was to protect workers with reduced immune defense to the same extent as those who were immune competent. A partial list of immune compromising conditions that present infection and disease challenges is presented in Table 2 (see bottom of page). This listing was expanded in 1997, when the CDC published comprehensive immunization recommendations for all healthcare workers.²

Compared to the general population, dental healthcare workers (DHCW) have greater risk of contracting several vaccine-preventable diseases because of their increased occupational exposure when providing patient care. The 1997 CDC immunization document, therefore, was a forerunner in the preparation of Guidelines for Infection Control in Dental Health-Care Settings—2003.³ Although there are a number of vaccine-preventable diseases, this article presents the importance of DHCW immunization for two—influenza and hepatitis B.

Routine direct contact with patients’ mouths and the generation of bioaerosols during patient treatment place dental staff at a particularly high risk for this respiratory infection. Influenza vaccination, therefore, is strongly recommended for DHCW. It reduces time lost from work and minimizes viral transmission from an infected DHCW to patients. Annual immunization is recommended for all HCW, particularly those who have diabetes, suffer from severe anemia, chronic pulmonary, cardiovascular, or renal disease, or are older than 65. This trivalent vaccine is administered via intramuscular injection, stimulating rapid antibody synthesis within two weeks in healthy adults. Maximal serum immunoglobulin concentration is detected at four to six weeks post-vaccination.

The viruses contained in the influenza vaccine are grown in chicken embryo cultures and are inactivated with formalin to minimize the amount of residual egg protein in the vaccine. The virus then splits into its components. The absence of any live virus in the vaccine precludes it from causing the flu in those vaccinated.

The CDC, in conjunction with public health agencies in other countries, revises virus content of the vaccine each year to incorporate up to three new emerging strains that are predicted to be prevalent for the upcoming flu season. When the vaccine contains the prevalent strains of viral organisms in a given year, the incidence of influenza is reduced by as much as 90% in those immunized. Because at least one to two of the strains used in a vaccine one year may be replaced by other emerging influenza strains the next year, immunity is temporary, and annual re-immunization is required.

As far as occupational risks for dental workers, the findings of an initial study conducted during the 1972 annual session of the American Dental Association (ADA) demonstrated dental professionals had a much higher occupational risk for HBV than the general population. In that study, 1,245 GPs were screened for hepatitis B surface antigen (HBsAg) and antibodies against that viral antigen (anti-HBs). Although only 3.3% of the dental students or private practice dentists screened gave a positive hepatitis B disease history, serologic assays performed on collected blood specimens showed 13.6% had positive serologic tests for previous HBV infection. Subsequent investigation substantiated and expanded these data, showing potential HBV transmission from infected dentists to patients during treatment.¹³

Any hepatitis B prevention program involves administering a vaccine. Primary immunization with hepatitis B vaccine consists of three intramuscular doses (1.0 mL each). After the initial dose, the second and third doses should be administered at one and at six months, respectively. Adherence to this prescribed regimen results in 90% to 95% of vaccinated adults demonstrating protective levels of anti-HBs (Table 4 see bottom of page).