Vaccination policy against hepatitis A in Italy

In Italy, improved sanitation and living conditions have led to a decline in the rate of hepatitis A infection among children generating an increasing proportion of adults susceptible to this virus. Shellfish consumption is a major source of infection while person to person transmission is important in the spread of infection and in the maintenance of outbreaks. Thus prevention of secondary HAV infection is a crucial point. A randomised controlled trial of hepatitis A vaccine in household contacts of people with sporadic HAV infection in Italy has shown a protective efficacy of 82% (CI 20-96%). The two secondary infections in the vaccine group were symptomless, suggesting that the disease expression may be weaker in vaccinated subjects.     

Vaccination against hepatitis viruses in Poland

At present, two etiologic varieties of viral hepatitis (VH) can be directly vaccine-preventable: VH type A and VH type B. In addition, VH type D can be prevented indirectly through vaccination against VH-B. The first commercially available vaccine against VH-B appeared in 1981 and was human plasma-derived. After several years, it has generally been replaced by a recombinant type of vaccines. The obvious benefits of vaccination against VH-B prompted its introduction into the national immunization program in Poland in 1989. At that time, vaccination was offered free of charge to high-risk groups: newborns of HBsAg-carrier mothers, health-care workers, students: at medical schools, nursing schools, medical technology schools, and caretakers at institutions for mentally retarded persons. However, similarly to the experiences of other countries, observations in Poland indicated that such a targeted strategy fails to induce major epidemiological changes. In 1989 and in 1993, the incidence of VH-B per 100000 was 40.3 and 34.6, respectively. In addition, during these years, the incidence of V-B per 100000 children aged 0-4 years was 20.0 and 38.4, respectively. It has been decided that vaccination against VH-B will be obligatory for all newborns beginning from 1993. Due to financial constraints, it has been introduced in three phases, and since 1996, all newborns in Poland have been vaccinated. Already in 1993, three additional risk groups have been offered vaccination: patients with chronic diseases, patients awaiting planned surgery, and persons coming into close contact with acute VH-B or chronically HBV-infected individuals. In 1999, the incidence of VH-B per 100000 was 9.1/100000, and it may be assumed that vaccination helped to decrease the incidence of VH-B in Poland. The country experience with vaccination against VH-A is still limited. At present, it is recommended for children and adolescents and people dealing with food distribution, as well as for several other groups of people, such as travellers or long-term visitors (soldiers, missionaries, diplomats) to the endemic regions of the world. It has also been recommended in connection with natural disasters such as floods occurring in a large area of Poland in 1997.     

Vaccination against hepatitis B in health care workers

Hepatitis B is the most important infectious occupational disease for health care workers. The high risk of being infected is the consequence of the prevalence of virus carriers in the assisted population, the high frequency of exposure to blood and other body fluids and the high contagiousness of hepatitis B virus (HBV). Vaccination is able to prevent the most threatening consequences of the infection (acute disease and chronic carriage) in responders, even after loss of detectable antibodies. Non-responders to the primary series may benefit from administration of up to three more doses of vaccine (40-70% of initial non-responders show seroconversion to the new series). However, newly developed vaccines that seem more immunogenic are presently under evaluation and should further decrease the number of non-immune workers in the near future. In the mean time, coverage with standard vaccines should be improved also by supplying complete information on the risks of hepatitis B and on the safety and efficacy of active immunisation.     

Vaccination against hepatitis B in low endemic countries

A mathematical model that takes transmission by sexual contact and vertical transmission into account was employed to describe the transmission dynamics of hepatitis B virus (HBV) and vaccination against it. The model is an extension of a model by Williams et al. (Epidemiol Infect 1996: 116; 71-89) in that it takes immigration of hepatitis B carriers from countries with higher prevalence into account. Model parameters were estimated from data from The Netherlands where available. The main results were that, given the estimates for the parameters describing sexual behaviour in The Netherlands, the basic reproduction number R0 is smaller than 1 in the heterosexual population. As a consequence, the immigration of carriers into the population largely determines the prevalence of HBV carriage and therefore limits the possible success of universal vaccination. Taking into account the prevalence of hepatitis B carriage among immigrants and an age-dependent probability of becoming a carrier after infection, we estimate that a fraction of between 5 and 10% of carrier states could be prevented by universal vaccination.     

Vaccination challenges and strategies against long-lived Toxoplasma gondii

Since the discovery of Toxoplasma gondii in 1908, it is estimated that one-third of the global population has been exposed to this ubiquitous intracellular protozoan. The complex life cycle of T. gondii has enabled itself to overcome stress and transmit easily within a broad host range thus achieving a high seroprevalence worldwide. To date, toxoplasmosis remains one of the most prevalent HIV-associated opportunistic central nervous system infections. This review presents a comprehensive overview of different vaccination approaches ranging from traditional inactivated whole-T. gondii vaccines to the popular DNA vaccines. Extensive discussions are made to highlight the challenges in constructing these vaccines, selecting adjuvants as well as delivery methods, immunisation approaches and developing study models. Herein we also deliberate over the latest and promising enhancement strategies that can address the limitations in developing an effective T. gondii prophylactic vaccine.     

Vaccination strategies

By nature of their long-term deployment in challenging areas of the world, expatriate employees and their dependents are at increased risk for a number of infectious diseases. Targeted immunization strategies may decrease this risk. Expatriate employees and their dependents should be immunized before deployment, and programs should be established to provide booster immunizations if the risk is ongoing. When considering work-force productivity, work-force infectivity, and the common good, careful consideration should be given to establishing at least a basic immunization program for in-country nationals and their dependents.     

Vaccination strategies to protect children against seasonal and pandemic influenza

To protect children against infection with seasonal influenza viruses, this age group is vaccinated annually in some countries. However, currently used inactivated seasonal influenza vaccines do not protect well against antigenically distinct pandemic influenza virus strains. Furthermore, annual vaccination may prevent infection with seasonal influenza viruses and subsequently the induction of heterosubtypic immunity. Therefore, the development of influenza vaccines that induce broad protective immunity should be considered a priority. In the absence of such vaccines children that are vaccinated annually against seasonal influenza should in a pandemic scenario also receive pandemic vaccines as soon as these become available. In order to protect young infant under six months of age for which no vaccines are registered at present, vaccination of pregnant women should be considered. This would afford protection through maternally derived antibodies. In addition, vaccination of close family members of young infants is recommended, to prevent transmission within the household.     

Vaccination against hepatitis B and the risk of multiple sclerosis

A paper on sclerosis multiplex as sequellae of vaccination against hepatitis B with recombinant vaccine was published in the journal of "Neurology" in September 2004. Problem was evaluated in United Kingdom on the ground of General Practice Research Database (GPRD). In 1996 similar problem was evaluated with negative results in several studies. Just now in opinions of many institutions as well as many persons vaccination against hepatitis B with recombinant vaccine should be continued in similar way as it was performed to this time.     

Vaccination strategies for control of community outbreaks of hepatitis A: A comparison of two outbreaks in England

In August 2015 two community outbreaks of hepatitis A virus (HAV) occurred in sub-urban communities in Northern England. Each was managed by an independent outbreak control team. In outbreak one, mass vaccination was deployed targeting a residential area and two schools, while in outbreak two, vaccination was reserved for household-type contacts of cases. The highest vaccination uptake was achieved in the school settings (82% and 95%). These case studies illustrate the range of approaches that can be used and the factors that influence decision-making in response to a hepatitis A community outbreak. Both outbreaks likely started from importation(s) of HAV by returning travellers and spread through extended social networks and the local community. Vaccination strategies were selected based on hypotheses about transmission pathways, which were informed by evidence from oral fluid (OF) testing of asymptomatic contacts. More evidence about the effectiveness of mass vaccination in community outbreaks of hepatitis A in low endemicity settings is needed. Hepatitis A guidelines should include recommendations for the use of mass vaccination and OF testing in outbreaks.     

Vaccination against pneumococci and hepatitis B in the Dutch National Immunisation Programme

All infants in the Netherlands, which are born after March 2006, receive additional vaccinations at the age of 2, 3, 4 and 11 months to protect them against pneumococcal infections. During the same visit to a consultation bureau, the children also receive a combination vaccine against diphtheria, pertussis, tetanus, poliomyelitis and Haemophilus influenzae (DTPa-IPV-Hib). Children of which at least one parent was born in a country where hepatitis B occurs relatively often are also vaccinated in the Netherlands against hepatitis B. This currently pertains to about 15% of all newborns. These children now receive a new combination vaccine in which a hepatitis B component has been added to the DTPa-IPV-Hib components. They will receive this combination vaccine 4 times. This combination vaccine is given during the same visit as the pneumococcal vaccination. Although pneumococcal vaccination may have a somewhat negative effect on the immune response to hepatitis B, it is expected that the new 4-fold vaccination schedule will induce good and long-lasting protection against hepatitis B in the vast majority of the children. About 700 children are born out of mothers infected with hepatitis B each year in the Netherlands. In the new vaccination schedule, they now receive 5 active vaccinations against hepatitis B and are examined serologically on an individual basis in order to detect breakthrough infections. This will also generate greater insight into the efficacy of the different vaccination schemes and intervention programmes to prevent vertical transmission of the virus.     

Vaccination strategies in developing countries

By 1990 it is hoped that all of the world's infants will have access to immunization services and that these services will then continue indefinitely. The link between people and health services, including immunization, can only be forged and maintained by an effective system of delivery and support to all health workers. A careful choice of strategies for this delivery system and an understanding of local cultural attitudes and behaviour is vital if this link is to be effective. Health workers will have to be trained and then supported in the field by regular contact with their supervisors. They will also need continuous, reliable, predictable and adequate supplies of equipment, drugs, vaccines, fuel and money, including salaries. Immunization is cost effective as a health intervention, but an effective programme of immunization can contribute much more than just vaccines, if it is developed in the context of primary health care (PHC) as originally proposed in 1978 at the conference in Alma Ata.     

Vaccination against hepatitis B virus in workers of a general hospital in Athens

BACKGROUND: Protection against hepatitis B virus infection by vaccination is considered to be an important preventive measure for health care workers. OBJECTIVES: Investigation of vaccination coverage against hepatitis B virus in health care workers of a regional general hospital in Athens and assessment of predictive factors possibly associated with the likelihood of vaccination. METHODS: In a cross-sectional study, a questionnaire survey was carried out on 175 health care workers of a regional general hospital in Athens. The questionnaire included questions concerning socio-demographic factors, HBV vaccination status and reasons for non-vaccination, as well as questions about knowledge of routes of transmission and the complications of HBV infection. Compliance with preventive practices against HBV infection was also assessed. RESULTS: Overall vaccination coverage was 57.1%. Logistic regression analysis revealed that occupation and use of gloves were independently associated with the likelihood of vaccination against HBV Doctors recorded an odds ratio (OR) for vaccination of 4.45 in comparison with nurses/paramedics. Health care workers who wore gloves always/most times demonstrated an odds ratio of 2.79 for vaccination against HBV in comparison with those who never/rarely used them. CONCLUSIONS: Our study illustrates the characteristics of health care workers with lower prevalence of vaccination against HBV in a representative sample of these workers in a regional general hospital in Athens: nurses/paramedics, those with low level of compliance with use of gloves, and those in non surgical departments. Educational interventions as part of a vaccination programme and continuing education on universal precautions could help increase HBV vaccination coverage among health care workers of the hospital under study.