RESUMO
BACKGROUND: Studies showed that HBV vaccination and consequent level of antibody are not completely adequate among dentists despite performance of highly exposure prone procedures. OBJECTIVES: The objectives of the study were to evaluate the levels of responsiveness to HBV vaccine and to determine the occupational factors associated among dental staff. MATERIALS AND METHODS: In total, 1612 dental health care workers were recruited. The level of anti-HBs was tested using a commercially enzyme-linked immunosorbent assay (ELISA). Data on demographic, risk factors associated with dental practice and level of protective procedures and occupational exposure aspects were collected through self-reported questionnaires. RESULTS: Of 1538 vaccinated individuals, 55 (3.7%), 126 (8.4%) and 1309 (87.9%) had received one, two and full three doses of vaccine, respectively. One-hundred-seventy-six (11.5%) were nonimmune (anti-HBs < 10 IU/mL) and 1362 (88.5%) were immune (anti-HBs > 10 IU/ mL). 392/542 (72.3%) of dentists who received their third dose of vaccination less than five years before the commencement of study were completely immune compared to those who had completed all three recommended doses in a longer period (308/491, 64.3%) (P = 0.001). Fifty-eight (3.59%) of participants did not receive any HBV vaccine at all; however, they had positive results for anti-HBs, indicating a past HBV infection. Statistically, the levels of anti-HBs were significantly associated with gender, age, duration of dental practice engagement and regularly use of mask, glasses and shield. CONCLUSIONS: Since dental care workers have a high risk of exposure to hepatitis virus, they should be advised to receive hepatitis B vaccine and it should be confirmed if they have acquired immunity to HBV by testing the level of anti-HBs.
RESUMO
To date, no studies have provided data on hepatitis B virus (HBV) prevalence among asymptomatic, healthy human T-lymphotropic virus (HTLV-I) positive carriers. This sero- and molecular epidemiology study was performed on patients in the Northeast of Iran, which is an endemic area for HTLV-I infection. A total of 109 sera were collected from HTLV-I positive healthy carriers who were admitted to Ghaem Hospital, Mashhad City. All were tested for HBV serology and subsequently, real time PCR was carried out on the samples, regardless of the results of the serology. Standard PCR and direct sequencing were applied on positive samples. All cases were negative for HBsAg, Anti-HBc, and anti-HBs were positive in 34 (31.1%), and 35 (32%) individuals, respectively. There were 19 (17.4%) cases that were positive only for anti-HBs, and they had already received HBV vaccine. 16 (15%) were positive for both anti-HBs and anti-HBc, indicating a past-resolved HBV infection. 18 (16.5%) were isolated as anti-HBc, and 56 (51.3%) were negative for all HBV serological markers. Only one subject (0.9%) had detectable HBV DNA (2153 copy/ml), and assigned as being an occult HBV infection. The low prevalence of HBsAg, despite the high percentage of anti-HBc positive cases, might be related to the suppression effect of HTLV-I on surface protein expression. The low prevalence of HBV infection among HTLV-I positive healthy carriers from an endemic region, indicates that the epidemiology of HTLV-I and HBV coinfection is related to the endemicity of HBV in that region, rather than HTLV-I endemicity.
