Introduction Of Vaccination Program Research Articles

The presence of bluetongue virus serotype 8 RNA in Belgian cattle since 2008

After a short winter break, bluetongue virus serotype 8 was responsible in 2007 for a large-scale epidemic among ruminant populations in Western Europe. Little is known about the mechanisms allowing the virus to survive winter conditions. A yearly mass vaccination of cattle and sheep started in spring 2008, which was recognized as successful in terms of clinical protection, but occult circulation of the bluetongue virus has not been adequately addressed. We studied the carriage of bluetongue RNA in the spleen of cattle in the vector-free period and the circulation of bluetongue virus in cattle populations in Belgium since the introduction of vaccination programmes. Overall, the results presented here show evidence for the long-term carriage of bluetongue virus RNA in the spleen of cattle and demonstrated a low but significant circulation and transplacental transmission of bluetongue virus in Belgian cattle in 2009, with apparent disappearance in 2010.

Seroprevalence of hepatitis B and C infection markers among children and adolescents in the southern Brazilian region

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections account for a substantial proportion of liver diseases worldwide. The aim of this study was to determine the prevalence of HBV and HCV serological markers among children and adolescents and verify the epidemiology of the HBV infection over than a decade of the introduction of vaccination program. Serologic markers to HBsAg, total anti-HBc and anti-HCV had been tested in 393 samples. The seropositivity for HBsAg was 0.76% and for total anti-HBc was 1.02%. Copositivity between HBsAg and total anti-HBc was verified in 0.76% of the analyzed samples. There was no seropositivity for anti-HCV marker. The seroprevalence of HBV infection markers among children and adolescents in the southern Brazilian region is high compared to that reported in other countries. Preventive measures, such as educational activities in addition to the universal childhood HBV vaccination, should be initiated in order to reduce the morbimortality and the economic burden associated with the disease.

Dynamic models of pneumococcal carriage and the impact of the Heptavalent Pneumococcal Conjugate Vaccine on invasive pneumococcal disease

BackgroundThe 7-valent pneumococcal conjugate vaccine has been introduced in national immunisation programmes of most industrialised countries and recently in two African GAVI eligible countries (Rwanda and The Gambia). However the long term effects of PCV are still unclear, as beneficial direct and herd immunity effects might be countered by serotype replacement.MethodA dynamic, age-structured, compartmental model of Streptococcus pneumoniae transmission was developed to predict the potential impact of PCV7 on the incidence of invasive disease accounting for both herd immunity and serotype replacement effects. The model was parameterised using epidemiological data from England and Wales and pre and post-vaccination surveillance data from the US.ResultsModel projections showed that serotype replacement plays a crucial role in determining the overall effect of a PCV7 vaccination programme and could reduce, negate or outweigh its beneficial impact. However, using the estimate of the competition parameter derived from the US post-vaccination experience, an infant vaccination programme would prevent 39,000 IPD cases in the 20 years after PCV7 introduction in the UK. Adding a catch-up campaign for under 2 or under 5 year olds would provide a further reduction of 1,200 or 3,300 IPD cases respectively, mostly in the first few years of the programme.ConclusionsThis analysis suggests that a PCV vaccination programme would eradicate vaccine serotypes from circulation. However, the increase in carriage of non-vaccine serotypes, and the consequent increase in invasive disease, could reduce, negate or outweigh the benefit. These results are sensitive to changes in the protective effect of the vaccine, and, most importantly, to the level of competition between vaccine and non-vaccine types. The techniques developed here can be used to assess the introduction of vaccination programmes in developing countries and provide the basis for cost-effectiveness analyses.

Review article: Hepatitis B and dialysis

The incidence of hepatitis B virus (HBV) infection in dialysis populations has declined over recent decades, largely because of improvements in infection control and widespread implementation of HBV vaccination. Regardless, outbreaks of infection continue to occur in dialysis units, and prevalence rates remain unacceptably high. For a variety of reasons, dialysis patients are at increased risk of acquiring HBV. They also demonstrate different disease manifestations compared with healthy individuals and are more likely to progress to chronic carriage. This paper will review the epidemiology, modes of transmission and diagnosis of HBV in this population. Prevention and treatment will be discussed, with a specific focus on strategies to improve vaccination response, new therapeutic options and selection of patients for therapy.

Seroprevalence of hepatitis B surface antigen among pregnant women in Jiangsu, China, 17 years after introduction of hepatitis B vaccine

Objective To estimate the prevalence of hepatitis B surface antigen (HBsAg) among pregnant women in Jiangsu Province, eastern China, 17 years after vaccination against hepatitis B virus (HBV) was introduced. Methods From August 2002 to July 2004, serum samples from 6398 women between 15 and 20 weeks of pregnancy and from 6 urban and 8 rural areas across Jiangsu Province were tested for markers of HBV. The results were then compared with the rates before 1980. Results The overall rates of 6.71% for HBsAg and 36.84% for anti-HBs were significantly lower and higher, respectively, than the prevaccination rates. The rate for HBsAg was lower in urban areas than in rural areas (5.75% vs 7.14%, P = 0.04). Although the rate used to be much higher in the northern part of Jiangsu Province, which is less prosperous than the southern part, the rates are now similar in both parts (6.60% vs 6.97%). Conclusion These findings demonstrate a drop in the prevalence of HBsAg among pregnant women in Jiangsu Province since the introduction of vaccination programs in 1980, and indicate that HBV infection can also be controlled in less prosperous areas.

Tetanus Developed in Gangrenous Perforation of Small Bowel

Tetanus is a neurologic disorder caused by a tetanospasmin released from Clostridium tetani and usually occurs following a stab wound or dirty abrasion. Tetanus is uncommon in Korea due to the introduction of vaccination programs. Furthermore, tetanus associated with a gangrenous perforation of the small bowel is extremely rare. We report a case of tetanus developed in a patient who was diagnosed with a gangrenous perforation of the small bowel. This is the first reported case in Korea.

Human Papillomavirus Vaccination in the Prevention of Cervical Neoplasia

Cervical cancer remains a major cause of morbidity and mortality for women worldwide. Although the introduction of comprehensive screening programs has reduced the disease incidence in developed countries, it remains a major problem in the developing world. The recent licensing of 2 vaccines against human papillomavirus (HPV) type 16 and HPV-18, the viruses responsible for 70% of cervical cancer cases, offers the hope of disease prevention. In this article, we review the role of HPV in the etiology of cervical cancer and the evidence to support the introduction of vaccination programs in young women and discuss the potential obstacles to widespread vaccination. In addition, we discuss the issues that remain to be elucidated, including the potential need for booster doses of the vaccine and the role of concomitant vaccination in men.

Seroepidemiology of hepatitis B virus infection in pregnant women in Catalonia (Spain)

Background In recent years there has been a substantial reduction in hepatitis B incidence as a result of routine vaccination of preadolescents and the selective vaccination of high risk groups and newborns of HBsAg+ mothers. Objectives To determine the prevalence of hepatitis B virus infection markers and of serologic markers of hepatitis B vaccination in a representative sample of pregnant women in Catalonia. Study design A representative sample was obtained by random cluster sampling (hospitals with maternity units) stratified by provinces. Anti-HBc, anti-HBs and HBsAg were determined using an ELISA test (Behring, Marburg, Germany). The crude and adjusted odds ratios for the sociodemographic variables analyzed were also calculated. Results The global prevalence of carriers of HBsAg+ was 0.1% (95% CI 0.0–0.3), that of hepatitis B infection (anti-HBc+) was 5% (95% CI 3.9–6.1) and that of serologic markers of vaccination (anti-HBs+ and anti-HBc−) was 16.4% (95% CI 14.5–18.2) The prevalence of infection increased with age from 3.0% (15–19 years age group) to 14.8% (40–44 years age group). The prevalence of anti-HBc+ was higher in women born in Asia (27.6%) and Africa (18.8%) than in those born in Spain (3.7%), Europe (3.3%) and America (4.6%), with the differences being statistically significant. Conclusions The results of this study confirm the change in the pattern of endemicity of hepatitis B infection in pregnant women in Catalonia after the introduction of vaccination programmes. They also confirm the increasingly important role played by immigration in the epidemiology of hepatitis B.

Recent distribution of vector mosquitoes and epidemiology of the diseases they transmitted in Taiwan

In Taiwan, the important mosquito-borne diseases include Japanese encephalitis (JE), dengue, and malaria, in which only JE is known as an endemic disease at present. This paper updates the current status of these disease vectors and pathogen activities to evaluate the disease risk. Since 2004, small to medium dengue outbreaks (202-2000 cases) have occurred annually, mostly in southern Taiwan where Aedes aegypti (L.) distributes. Occasionally, small outbreaks (smaller than 20) occurred in other areas without the presence of Ae. aegypti. Dengue virus infection in local vector population was detected sympatrically with the human cases in the same outbreak. JE cases have occurred sporadically after the introduction of vaccination program since 1968. The predominant species was Culex tritaeniorhynchus Giles (93.9%), followed by Cx. fuscocephala Theobald (3.4%), and Cx. vishnui Theobald (2.6%). Overall population densities were high, with the highest number of 37,440 per trap-night. JE virus was active in mosquito populations during May and June. The distribution of Anopheles minimus Theobald was limited to a few villages at the foothills of southern and eastern Taiwan. The highest numbers of An. minimus adults trapped per trap-night were between 23 and 206 in 6 villages. Chikungunya infection has been found in the travelers from endemic countries since 2007. In conclusion, the threat of these mosquito-borne diseases is increasing because of the frequent introductions of pathogens and the high densities of disease vectors in Taiwan.

Hepatitis B Management Costs in France, Italy, Spain, and the United Kingdom

To estimate the costs associated with the management of chronic hepatitis B (CHB) and its sequelae in France, Italy, Spain, and the United Kingdom from the perspective of the healthcare payer. The World Health Organization estimates that the disease sequelae related to hepatitis B account for 1 million deaths annually worldwide. Northern Europe is a low endemic area, while Mediterranean regions are classified as intermediate endemic areas. The introduction of vaccination programs in France, Italy, and Spain in recent years has lowered the hepatitis B incidence rates. The purpose of this study was to identify the medical management patterns of CHB patients in France, Italy, Spain, and the United Kingdom and estimate the economic burdens of CHB-related disease states for each country. A central questionnaire was used to collect data from specialist physicians in four countries, and responses were collated into management patterns for chronic active hepatitis, compensated and decompensated cirrhosis, and hepatocellular carcinoma. The average cost by disease state for each European country was found to increase across the identified disease states reflecting disease progression. Year-2001 average annual disease state costs per patient were estimated to be as follows: CHB, 1,093 euro-3,396 euro; compensated cirrhosis, 1,134 euro-3,997 euro; decompensated cirrhosis, 5,292 euro-8,842 euro; hepatocellular carcinoma, 3,731 euro-9,352 euro; and, from published sources, liver transplant surgery, 25,165 euro-84,568 euro. The cost of CHB is variable both within and between European countries. The association of disease progression with increased cost of disease management suggests that measures to prevent or delay its progression would be economically beneficial.

Outbreak of hepatitis A in the injecting drug user and homeless populations in Bristol: control by a targeted vaccination programme and possible parenteral transmission.

To study the use of hepatitis A virus (HAV) vaccination in controlling an outbreak of HAV in inner-city Bristol among injecting drug users (IDUs). To study whether hepatitis C virus (HCV) and hepatitis B virus (HBV) co-infection increases morbidity. Community-based cohort study. Avon Health Authority area, UK. All laboratory-confirmed cases of HAV infection notified in 2000. Administration of a targeted vaccination, education and liaison programme. Number of cases of HAV before and after introduction of HAV vaccination programme. Mortality and number of patients requiring hospital admission. Association of HCV and HBV co-infection with hospital admission. Ninety cases of HAV were reported in the first 6 months of 2000, of whom a substantial number were IDUs and/or inner-city hostel residents. In the second 6 months of 2000, following the introduction of a vaccination programme among homeless people, hostel residents, and IDUs, the number of HAV cases fell to 33. Sixteen patients had evidence of HCV co-infection. No patient had chronic HBV infection. Two patients died as a result of HAV, and two subsequently died from drug misuse. Fifty-six per cent of HCV-co-infected patients required admission to hospital compared with 28% non-HCV-co-infected patients. This is the first reported successful use of vaccination to control an outbreak of HAV in a population of IDUs and to prevent transmission to the wider population. HCV co-infection appears to increase the severity of HAV illness, as demonstrated by increased incidence of hospital admission.

Atopic eczema. What has caused the epidemic in industrialised countries and can early intervention modify the natural history of atopic eczema?

Atopic eczema (AE) has a lifetime prevalence of between 15 and 20% in industrialized countries, but a very low prevalence in rural Africa. The 'atopic eczema epidemic' has developed in industrialized countries within the last four decades. The disease has a strong genetic influence, so environmental factors must be responsible for the dramatic increase in disease prevalence. It is therefore fair to consider what interventions may change its prevalence. In this article, several factors are considered: the increased number of doctors in industrialized countries, the development of drugs like topical steroids and emollients, the 'demanding parents' and 'old mother' syndromes, introduction of vaccination programmes, allergen exposure, breastfeeding and the possible beneficial effects of probiotics. In 90% of children with AE, onset is before the age of 5. Its course runs over years. Approximately two out of three outgrow the disease between 7 and 12 years of age. Although its cause is unknown, type I allergic reactions are common and allergen avoidance has been attempted in many studies as a preventive measure in atopic dermatitis. However, results are rather disappointing. The use of probiotics, i.e. daily intake of Lactobacillus, has proven effective in preventing, or at least delaying, the development of atopic eczema. So has breastfeeding, although some studies cannot confirm its beneficial effect. Therapeutic interventions using antihistamines, desensitisation and control of skin inflammation using topical steroids have not proven successful in shortening the course of atopic eczema, although controlled studies are lacking. The use of emollients has, however, a documented effect in up to one of three children with mild atopic eczema. It will be interesting to observe if the new topical immuno-modulators, tacrolimus and pimecrolimus, may be able to shorten the natural course of the disease.

Epidemiology of pertussis in a West African community before and after introduction of a widespread vaccination program.

The control of pertussis remains a worldwide concern. Little has been documented about its epidemiology in Africa. The authors have studied pertussis in a prospective cohort of children in a rural West African community over a 13-year period comprising time before and after introduction of a vaccination program. Children under age 15 years who were residents of the Niakhar study area in Senegal were followed prospectively between January 1984 and December 1996 for the occurrence of pertussis. Morbidity and mortality rates were extremely high before the launch of immunization. Crude incidence was 183 per 1,000 child-years at risk under age 5 years, with a 2.8% case-fatality rate. After the introduction of the vaccination program, overall incidence dropped rapidly and dramatically-by 27% after 3 years and 46% after 6 years. The decline in incidence involved all age groups but was most substantial in the group under age 5 years and was particularly pronounced in unvaccinated infants. The median age of acquisition of the disease rose steadily with population vaccine coverage. This study shows the tremendous magnitude of the disease burden in children and the rapid decline after vaccination, and it suggests a strong herd-immunity effect.

Statistical analysis and prediction on incidence of infectious diseases based on trend and seasonality.

We proposed a prediction methodology for the incidence of infectious diseases using incidence data on measles and influenza for forty years in Japan. We also proposed a diagram that makes it possible to convey information on infectious disease incidence more attractively to a wider audience. This can be a useful tool for health promotion in the community. The obtained results are as follows: 1. It was advantageous to use data transformed by logarithm in statistical analysis of infectious disease incidence. 2. The incidences of measles and influenza exhibited strong seasonality. Measles was most frequent in June and influenza in February. 3. Long-term trends were extracted from the derived data obtained by eliminating seasonal effects from the original data. For measles, a decline was accelerated by the introduction of vaccination program in 1978. Influenza also showed a decline for these thirty years. 4. The observed incidence data were quite well predicted by only the trend and the seasonality. The squares of multiple regression coefficients of measles and influenza were 0.84 and 0.58, respectively. The analysis of the residuals suggested there was a possibility of improvement in prediction. 5. The improvement in prediction was attained by incorporating an autoregressive component of the residuals. As a result, the squares of multiple correlation coefficients of measles and influenza increased to 0.97 and to 0.79, respectively. 6. We finally proposed the TS-decomposition diagram to facilitate practical use of incidence data. In this diagram, current incidence data and predicted values for the near future are plotted on the plane where the trend and the seasonality are superimposed.(ABSTRACT TRUNCATED AT 250 WORDS)