Hepatitis vaccines

Survey of the level of anti-HBs antibody titer in vaccinated Iranian general dentists

Hepatitis B is an infectious disease to which dentists are susceptible. The main aim of this study was to determine the level of antibody titer and immunity in vaccinated Iranian general dentists. A total of 861 general dentists were invited to participate in this study; 598 persons who could recall their history of vaccination and consented to have blood samples taken were recruited. Demographic and work-related data were recorded, and anti-Hepatitis B surface antigen (anti-HBs-Ag) evaluations were measured using the enzyme-linked immunosorbent assay (ELISA). Of the 598 participants, 35 (5.9%) were nonimmune (anti-HBs <10 IU/l), 101 (16.9%) were relatively immune (anti-HBs = 10-99 IU/l), and 462 (77.3%) were completely immune (anti-HBs > or =100 IU/l). Only 218 (36.5%) of the dentists knew their HBs antibody titer. Fourteen (2.3%) persons reported receiving one dose and 65 (10.9%) had received two doses. The number of those who had received the three recommended doses totaled 519 (86.8%), 491 (82.1%) of them receiving their vaccine on schedule. Age, city, pack-years of smoking, years of smoking, and the interval between the last vaccination and the commencement of the study had a significant relationship to the antibody titer level, whereas sex, marital status, place of practice, smoking, and vaccination schedule were not related. Only 36.5% of the general dentists had checked their antibody titer. We, therefore, recommend that dentists, as a potential high-risk group, should know their level of anti-HBs antibody titer so that those who require revaccination can get treatment.

Cleavage of intracellular hepatitis C RNA in the virus core protein coding region by deoxyribozymes

Hepatitis C virus (HCV) infection represents an important global health problem. Current antiviral therapeutics for HCV have proven inadequate in stemming the disease process. A novel therapeutic strategy involves the use of deoxyribozymes, also known as DNA enzymes or DNAzymes. These catalytic DNA molecules, designed to target and cleave specific RNA sequences, have shown promise in in vitro experimental models for various diseases and may serve as an alternative or adjunct to current HCV drug therapy. We designed and tested several deoxyribozymes that can bind and cleave highly conserved RNA sequences encoding the HCV core protein in in vitro systems. One of these deoxyribozymes reduced the level of our HCV RNA target by 32% and 48% after 24 h of cell exposure when tested in human hepatoma and epithelial cell lines, respectively. As this deoxyribozyme showed significant cleavage activity against HCV core protein target RNA in human cells, it may have potential as a therapeutic candidate for clinical trial in HCV infected patients.

[Hepatitis A]

Hepatitis A infection is known since the ancient Chinese, Greek and Roman civilizations but the first documented report was published in the eighteenth century. The hepatovirus belongs to the Picornaviridae family, and carries a single strand RNA. There are 7 genotypes. Antibodies of the IgM and IgA classes, during natural infections, appear early in the serum, together with the first clinical manifestations of the disease, but they may also appear at the end of the first week of infection. There is a spectrum of clinical presentation: asymptomatic infection, symptomatic without jaundice and symptomatic jaundiced. A rare fatal form of hepatitis has been described. Diagnosis of the hepatitis A infection is confirmed by the finding of IgM anti-HAV antibodies, routinely performed using an ELISA test. Treatment is supportive. Intramuscular anti-A gamma globulin is used for passive immune prophylaxis, and there is an efficient vaccine for active immune prophylaxis.

Vaccines for viral diseases with dermatologic manifestations

Vaccines against infectious diseases have been available since the 1800s, when an immunization strategy against smallpox developed by Jenner gained wide acceptance. Until recently, the only vaccination strategies available involved the use of protein-based, whole killed, and attenuated live virus vaccines. These strategies have led to the development of effective vaccines against a variety of diseases with primary or prominent cutaneous manifestations. Effective and safe vaccines now used worldwide include those directed against measles and rubella (now commonly used together with a mumps vaccine as the trivalent MMR), chickenpox, and hepatitis B. The eradication of naturally occurring smallpox remains one of the greatest successes in the history of modern medicine, but stockpiles of live smallpox exist in the United States and Russia. Renewed interest in the smallpox vaccine reflects concerns about a possible bioterrorist threat using this virus. Yellow fever is a hemorrhagic virus endemic to tropical areas of South America and Africa. An effective vaccine for this virus has existed since 1937, and it is used widely in endemic areas of South America, and to a lesser extent in Africa. This vaccine is recommended once every 10 years for people who are traveling to endemic areas. Advances in immunology have led to a greater understanding of immune system function in viral diseases. Progress in genetics and molecular biology has allowed researchers to design vaccines with novel mechanisms of action (eg, DNA, vector, and VLP vaccines). Vaccines have also been designed to specifically target particular viral components, allowing for stimulation of various arms of the immune system as desired. Ongoing research shows promise in prophylactic and therapeutic vaccination for viral infections with cutaneous manifestations. Further studies are necessary before vaccines for HSV, HPV, and HIV become commercially available.