Investigation of the response to the enterobacterial common antigen after typhoid vaccination

Antibodies against the Salmonella typhi enterobacterial common antigen (ECA) and the O and H antigens were investigated in sera from healthy male subjects who had been previously vaccinated with the typhoid vaccine. No serological response to ECA was observed. Sera from subjects not previously vaccinated presented titers of ECA hemagglutinins which quantitatively were related to the presence ofH titers, but not to O agglutinins but with no statistical significance. The results are discussed in relation to the possible protective immunological mechanisms in typhoid fever.

Antimeasles antibodies in children submitted to different vaccination schedules

ln order to study the measles antibody behavior of three vaccination schedules, 684 children were divided into 4 Groups: Group A (341 vaccinated children under the age of one); Group B (101 children at the age of one); Group C (74 children under the age of one and one at the age of one); Group D (163 unvaccinated children with a history of measles in the past - Group control). Children of Group A presented lower rates and 25.9% of the age group under two did not show any measles antibodies. In Group B, all the children presented antibodies. In Group C onby 4.0% did not. In all age groups, the geometric mean HI antibody titers of Group A were lower than the valuesfound in the other groups. The age at vaccination was the factor of greater influence on the results of this study.

Clinical and epidemiological findings during a measles outbreak occurring in a population with high vaccination coverage

From March 1991 to April 1992, 250 measles suspected cases were studied in the Municipality of Niterói, State of Rio de Janeiro. The median age found was 11 years and 76.0% of the cases were in school age children. Exposure histories were present in 149 patients and schools were the most frequent sites of transmission (45.0%). Vaccination status was known for 127 studied cases and 76.4% of them had received measles vaccine before their first birthday. One or more complications were reported for 68 cases aitd in 8.9% of the studied cases hospitalization was required. Frequency of complications varied according to each age group studied and were more commonly encountered among children < 1 year of age (55.6%). The history of previous vaccination did not diminish the number of complications of the cases studied. The results of this work show changes in age distribution of measles leading to sizeable outbreaks among teenagers and young adults.

The FML (Fucose Mannose Ligand) of Leishmania donovani: a new tool in diagnosis, prognosis, transfusional control and vaccination against human kala-azar

The Fucose-Mannose Ligand (FML) of Leishmania donovani is a complex glycoproteic fraction. Its potential use as a tool for diagnosis of human visceral leishmaniasis was tested with human sera from Natal, Rio Grande do Norte, Brazil. The FML-ELISA test, showed 100% sensitivity and 96% specificity, identifying patients with overt kala-azar (p < 0.001, when compared to normal sera), and subjects with subclinical infection. More than 20% apparently healthy subjects with positive reaction to FML developed overt kala-azar during the following 10 months. In the screening of human blood donnors, a prevalence of 5% of sororeactive subjects was detected, attaining 17% in a single day. The GP36 glycoprotein of FHL is specifically reconized by human kala-azar sera. The immunoprotective effect of FML on experimental L. donovanii infection was tested in swiss albino mice. The protection scheemes included three weekly doses of FML, supplemented or not with saponin by the subcutaneous or intraperitoneal routes and challenge with 2x 10(7) amastigotes of Leishmania donovani. An enhancement of 80.0 % in antibody response (p<0.001) and reduction of 85.5 % parasite liver burden (p<0.001) was detected in animals immunized with FML saponin, unrespectivety of the immunization route.

Vaccination of C57BL/10 mice against cutaneous leishmaniasis using killed promastigotes of different strains and species of Leishmania

Antigenic extracts from five Leishmania stocks were used to vaccinate C57BL/10 mice. The Leishvacin® and PH8 monovalent vaccine yielded the highest IFN-gamma levels in the supernatants of spleen cell culture from vaccinated animals. Each single strain immunized group showed evidence of protective immunity six months after the challenge with promastigotes of Leishmania (Leishmania) amazonensis. No differences were detected between the vaccinated groups. It can be concluded that vaccines composed of single Leishmania stocks can provide protection to C57BL/10 mice against L. (L.) amazonensis infection.

Yellow fever virus isolated from a fatal post vaccination event: an experimental comparative study with the 17DD vaccine strain in the Syrian hamster (Mesocricetus auratus)

In order to investigate the pathogenicity of the virus strain GOI 4191 that was isolated from a fatal adverse event after yellow fever virus (YFV) vaccination, an experimental assay using hamsters (Mesocricetus auratus) as animal model and YFV 17DD vaccine strain as virus reference was accomplished. The two virus strains were inoculated by intracerebral, intrahepatic and subcutaneous routes. The levels of viremia, antibody response, and aminotransferases were determined in sera; while virus, antigen and histopathological changes were determined in the viscera. No viremia was detected for either strain following infection; the immune response was demonstrated to be more effective to strain GOI 4191; and no significant aminotransferase levels alterations were detected. Strain GOI 4191 was recovered only from the brain of animals inoculated by the IC route. Viral antigens were detected in liver and brain by immunohistochemical assay. Histothological changes in the viscera were characterized by inflammatory infiltrate, hepatocellular necrosis, and viral encephalitis. Histological alterations and detection of viral antigen were observed in the liver of animals inoculated by the intrahepatic route. These findings were similar for both strains used in the experiment; however, significant differences were observed from those results previously reported for wild type YFV strains.

Predictors of adherence to influenza vaccination for healthcare workers from a teaching hospital: a study in the prepandemic era

INTRODUCTION: Even before the 2009 pandemics, influenza in healthcare workers (HCW) was a known threat to patient safety, while Influenza vaccine coverage in the same group was generally low. Identification of predictors for HCW adherence to Influenza vaccination has challenged infection control committees. METHODS: Our group conducted a cross-sectional survey in December 2007, interviewing 125 HCWs from a teaching hospital to identify adherence predictors for Influenza vaccination. The outcomes of interest were: A - adherence to the 2007 vaccination campaign; B - adherence to at least three yearly campaigns in the past five years. Demographic and professional data were assessed through univariate and multivariate analysis. RESULTS: Of the HCWs interviewed, 43.2% were vaccinated against Influenza in 2007. However, only 34.3% of HCWs working in healthcare for more than five years had adhered to at least three of the last five vaccination campaigns. Multivariate analysis showed that working in a pediatric unit (OR = 7.35, 95%CI = 1.90-28.44, p = 0.004) and number of years in the job (OR = 1.32, 95%CI = 1.00-1.74, p = 0.049) were significant predictors of adherence to the 2007 campaign. Physicians returned the worst outcome performances in A (OR = 0.40, 95%CI = 0.16-0.97, p = 0.04) and B (OR = 0.17, 95%CI = 0.05-0.60, p = 0.006). CONCLUSIONS: Strategies to improve adherence to Influenza vaccination should focus on physicians and newly-recruited HCWs. New studies are required to assess the impact of the recent Influenza A pandemics on HCW-directed immunization policies.

Hepatitis B marker seroprevalence and vaccination coverage in adolescents in the City of Itajaí, State of Santa Catarina, Southern Brazil, in 2008

INTRODUCTION: Hepatitis B infection constitutes an important cause of morbidity and mortality worldwide. In Brazil, however, the current epidemiological situation is not clear. Considering the importance of establishing this prevalence, the aim of this study was to determine the prevalence of HBV markers in voluntary adolescents, junior high (secondary school) students, in the City of Itajaí, State of Santa Catarina, Brazil. METHODS: A seroepidemiological, transverse study was conducted with 353 randomly chosen adolescents from elementary school in 2008. Blood samples were analyzed for HBsAg, anti-HBc and anti-HBs. All analyses were conducted by automated microparticle enzyme immunosorbent assay (Abbott®, AxSYM system, Deerfield, IL, USA), according to the manufacturer's instructions. RESULTS: The prevalence of HBsAg was 0.6% (CI 95% 0.1 - 2.0), that of anti-HBc was 1.1% (CI 95% 0.3 - 2.9) and that of detectable anti-HBs was 83.6% (CI 95% 79.3 - 87.3). Hepatitis B vaccination coverage was 97.5% (CI 95% 95.2 - 98.8). CONCLUSIONS: These results demonstrate the success of the vaccination program against hepatitis B in the region studied and indicate that prevention strategies must be maintained and, if possible, expanded to contribute to the establishment of positive prevalence rates in all age groups.

Prevalence of hepatitis B virus infection and carriage after nineteen years of vaccination program in the Western Brazilian Amazon

INTRODUCTION: Reductions in the prevalence of hepatitis B virus (HBV) infection and carriage, decreases in liver cancer incidence, and changes in patterns of liver dysfunctions are described after hepatitis B vaccination. METHODS: We conducted a population-based seroprevalence study aimed at estimating the HBV prevalence and risk of infection in the rural area of Lábrea following nineteen years of HBV vaccination. RESULTS: Half of the subjects showed total anti-HBc of 52.1% (95% CI 49.6-54.7). The HBsAg prevalence was 6.2% (95% CI 5.1-7.6). Multivariate analysis showed an inverse association between HBV infection and vaccination (OR 0.62; 95% CI 0.44-0.87). HBsAg remained independently associated with past hepatitis (OR 2.44; 95% CI 1.52-3.89) and inversely to vaccination (OR 0.43; 95% CI 0.27-0.69). The prevalence of HBeAg among HBsAg-positive individuals was 20.4% (95% CI 12.8-30.1), with the positive subjects having a median age of 11 years (1-46) p=0.0003. CONCLUSIONS: We demonstrate that HBV infection is still an important public health issue and that HBV vaccination could have had better impact on HBV epidemiology. If we extrapolate these findings to other rural areas in the Brazilian Amazon, we can predict that the sources of chronic infected patients remain a challenge. Future studies are needed regarding clinical aspects, molecular epidemiology, surveillance of acute cases, and risk groups.

Antibody levels in children after 10 years of vaccination against hepatitis B: a brazilian community-based study

INTRODUCTION: It is known that the hepatitis B (HB) vaccine is effective, but it is alarming that sudden drops of antibody levels may coincide with the onset of adolescence. METHODS: Antibody levels against HB vaccine surface antigen (anti-HBs) and HB vaccine core antigen (anti-HBc) were measured on the blood samples of children with a mean age of 11.4 years. RESULTS: About 54.8% had protective levels of anti-HBs. Of those who were anti-HBc-positive (4.4%), an average of 218.4 anti-HBs mIU/mL was found. CONCLUSIONS: Immunological protection was found in the majority of children. However, more studies are needed to elucidate the heritability of nonresponders and establish strategies against such events.

Hepatitis B revaccination for healthcare workers who are anti-HBs-negative after receiving a primary vaccination series

INTRODUCTION: This study aimed to evaluate the response to hepatitis B (HB) revaccination of healthcare workers (HCW) who are negative for antibodies to HB surface antigen (anti-HBs) after a complete vaccination series. METHODS: HCW whose anti-HBs test was performed > 90 days after a HB vaccination course were given a 4th dose. A post-vaccination test was done within 30 to 90 days. RESULTS: One hundred and seventy HCW were enrolled: 126 (74.1%) were anti-HBs-positive after the 4th dose. CONCLUSIONS: Rechecking anti-HBs after the 4th HB vaccine dose is a practical approach in case of post-vaccination tests performed >90 days after the full vaccination course.

Prevalence of influenza and adherence to the anti-flu vaccination among elderly

INTRODUCTION: The flu, a condition that can affect the elderly by increasing the risk of serious complications can be prevented through vaccination. Estimate the prevalence of signs and symptoms suggestive of influenza in a group of elderly either vaccinated or unvaccinated against influenza was the objective this study. METHODS: This is a cross-sectional study performed in a Brazilian City. A structured questionnaire was employed to identify the presence of signs and symptoms of influenza in individuals aged 60 years or over. For analysis of associations between variables the prevalence ratio (PR) and its 95% confidence interval (95% CI) were used. RESULTS: One hundred ninety-six participants were interviewed, of whom 57.7% were female. The average age was 69.7 years. About 25% of the vaccinated and 20% of the unvaccinated in 2009, and 25% of the vaccinated and 22.5% of the unvaccinated in 2010 reported having the flu. Among the vaccinated and unvaccinated in 2009 and 2010, there was no verified association between vaccination and influenza (PR=1.24; [95% CI: 0.63-2.43] and PR=1.11; [95% CI: 0.59-2.09], respectively). CONCLUSIONS: This study suggests that, among the elderly selected, the vaccination coverage for influenza is below the ideal, even with projection of the best indices for 2011 (~ 84%). The data on vaccination and disease protection needs further research; however, the results point to the need for measures to better clarify to this population about the disease, its complications and the benefits of vaccination, in addition to combatting the stigma related to low adherence.