Intradermal vaccination of adults with three low doses (2 µg) of recombinant hepatitis B vaccine. II. Persistence of immunity and induction of immunologic memory

Hepatitis B: knowledge, vaccine situation and seroconversion of dentistry students of a public university

BACKGROUND

Viral hepatitis B (VHB) is an occupational risk for dentists. It is necessary that dental students start clinical practice immunized with the vaccine, response monitored and informed about the means of transmission of the disease. Rarely, there are studies, which evaluate concomitantly knowledge of these academics and their vaccine situation.

OBJECTIVES

To evaluate the knowledge about Hepatitis B, the vaccine situation and the immunization status of dental students and to investigate the probable correlation between the status of immunization, vaccination membership and adherence to the test of seroconversion and associated factors.

PATIENTS AND METHODS

189 students from the dentistry course at the Federal University of Piaui (UFPI) who attended from the 3rd to 9th period were invited to participate in the research. Their knowledge about HBV, attitude regarding protection and their vaccine situation were assessed through a self-administered form. Antibodies against surface antigens of Hepatitis B virus (Anti-HBs) and against the antigens of the virus nucleous of Hepatitis B (Anti-HBc total) were measured qualitatively using the enzyme-linked immunosorbent assay (ELISA).

RESULTS

Of the 179 students surveyed, 58.1% knew about the degree of virulence of the Hepatitis B virus (HBV). As to the means of transmission, 98.3% considered blood transmission, 82.6% plates and cutlery, 15.6% cough and 12.3% vertical transmission. Most students (87.4%) knew that they should take 3 doses of the vaccine and 62.2% completed the immunization schedule. A minority of students (48.6%) knew the about the Anti-HBs test and 5.6% took the test. Among the students who reported having taken three doses of the vaccine, 12.5% were not seroconverted. There was no significant correlation between the variables.

CONCLUSIONS

Dental academics were unsure about the means of infection and prevention against HBV. Many of them had not completed the immunization scheme and did not have the test of seroconversion. The serological analysis revealed unprotection, even after students completed the vaccination schedule.

A low-dose intradermal hepatitis B vaccine programme in health-care workers and students is highly effective and cost saving: a retrospective follow-up survey in the clinical setting

OBJECTIVE

To evaluate compliance, serologic response and the cost-benefit of a low-dose intradermal hepatitis B vaccination programme, followed by intramuscular boosters in non-responders.

MATERIAL AND METHODS

The study comprised a retrospective survey of 1521 health-care workers and 968 students. Response was defined as hepatitis B antibody titres > or =10 IU/L. Non-response included vaccinees with undetectable antibodies and a hypo-response if antibodies were detectable.

RESULTS

Overall, 2145/2489 (86%) subjects completed the intradermal series, whereof 1840/2489 (74%) complied with the serological check-up. Response was achieved in 1517/1840 (82.5%), whereas 107/1840 (5.8%) had a hypo-response and 216/1840 (11.7%) had an undetectable response. In a logistic regression model, younger age (odds ratio 0.73 (95% CI: 0.65-0.82, p<0.001)) and female gender (odds ratio 2.16 (95% CI: 1.67-2.80; p<0.001)) were predictive of response. In hypo-responders and those with undetectable responses, 43/46 (94%) and 71/136 (52%), respectively, had a response after the first intramuscular booster. Hence, in compliant vaccinees an overall seroprotection rate of 94% was reached after a single intramuscular booster. A cost-benefit analysis indicated a cost reduction exceeding 50% compared to a standard intramuscular vaccine regimen.

CONCLUSIONS

In the clinical setting, a low-dose intradermal hepatitis B vaccination programme, followed by intramuscular boosters to non-responders, is effective and cost saving.

Immunogenicity and safety of combined intradermal recombinant Hepatitis B with BCG vaccines at birth

This randomized, prospective, non-inferiority study aimed to quantify anti-HBs titers induced by recombinant Hepatitis B vaccine from healthy infants vaccinated with combined Hepatitis B and Bacillus Calmette-Guérin (BCG) vaccines (HbsAg 10 microg plus BCG suspension 0.1mg) and compare them to titers obtained with separated vaccines. Infants were immunized at birth either with combined intradermal (ID) BCG and Hepatitis B or ID BCG alone and intramuscular (IM) Hepatitis B. Both groups received IM Hepatitis B at 1 and 6 months of age. After the third dose anti-HBs titers > or =10 IU/mL were observed in 99% of vaccinees and > or =1000 IU/mL in 71%. There were no adverse events in both groups. Combination of HbsAg with BCG as first dose did not modify the profile of the humoral immune response for Hepatitis B indicating safety and immunogenicity of this vaccine in newborn.

Immunization for hospital staff

PURPOSE OF REVIEW

In this review the recent literature on the topic of immunization of healthcare workers is assessed. The emphasis lies on immunizations that are directly related to the risks of healthcare workers in the workplace.

RECENT FINDINGS

Acceptance of influenza immunization by healthcare workers remains too low, whereas other preventive measures such as hepatitis B vaccination are usually not disputed. Efforts to improve the knowledge of healthcare workers about influenza, its epidemic potential and clinical consequences have contributed to higher immunization rates in some hospitals. Immunization against varicella zoster virus does not result in immunity in all vaccinated persons. This lack of complete protection has infection-control implications, namely the recommendation to wear a mask when caring for clinical cases, regardless of the immunization status. The topic of immunization of healthcare workers has recently been dominated by the discussion of smallpox vaccination, which was promoted by the American public-health authorities for some groups of healthcare workers.

SUMMARY

Immunization is a preventive measure that is highly cost-effective. Healthcare workers are responsible for the safety and well-being of their patients and should do their utmost to prevent the transmission of infectious pathogens to them. Another positive result of the adherence of healthcare workers to the recommended immunization schedule is the improved self-protection at the workplace. Immunization against some highly contagious infectious agents has been recommended for many years. The list is now being expanded again by the recommendation of smallpox vaccination. Regarding this indication, several questions and safety issues must be resolved in order to positively influence the currently rather sceptical attitude of healthcare workers towards this vaccine.