Vaccination Era (vaccination + era)

Distribution by Scientific Domains

Selected Abstracts

Cycles and synchrony: two historical ,experiments' and one experience

Ottar N. Bj°rnstad
Summary 1.,Theoretical models predict that spatial synchrony should be enhanced in cyclic populations due to nonlinear phase-locking. 2.,This is supported by Rohani et al.,s (1999) comparison of spatial synchrony of epidemics in two childhood diseases prior to and during the vaccination era. Measles is both more synchronous and more cyclic before vaccination. Whooping cough, in contrast, is more synchronous during the vaccination era, during which multiannual fluctuations are also more conspicuous. 3.,Steen et al. (1990) analysed historic records of cyclic rodents, to show that cyclicity was lost during the early part of the 20th century. I reanalyse the data, and find that the loss of cyclicity is associated with loss of regional synchrony. 4.,I use a coupled map lattice model to show that imperfect phase-locking provides an alternative explanation for regionwide synchrony of cyclic populations. [source]

Decreasing incidence of hepatocellular carcinoma among children following universal hepatitis B immunization

Mei-Hwei Chang
Abstract: Hepatocellular carcinoma (HCC) is one of the 10 most common malignant tumors worldwide. Chronic infection with hepatitis B or C virus is closely related to hepatocarcinogenesis. The outcome of current therapies for HCC is not satisfactory. Prevention is the best way to control HCC. Among the various strategies of HCC prevention, immunization against hepatitis B virus infection is the most effective. Universal hepatitis B immunization has proved to be effective in reducing the incidence of HCC to 1/4,1/3 of that in children born before the hepatitis B vaccination era in Taiwan. The problems we face in achieving global control of hepatitis-related HCC include: (1) no effective vaccine for the prevention of hepatitis C and its related HCC; (2) no immunization program for hepatitis B in areas with inadequate resources; (3) poor compliance to the immunization program as a result of ignorance, anxiety, or poverty; and (4) vaccine failure. Integration of the hepatitis B vaccination program into the expanded program of immunization for all infants throughout the world will be most urgent and important for HCC control. The reduction of the incidence of HCC will be seen in adults 30,40 years of age after the launch of the universal hepatitis B vaccination program. This concept of cancer vaccine can be applied to other infectious agents and their related cancers. [source]

Cervical mycobacterial lymphadenitis in Swedish children during the post-BCG vaccination era

Bj÷rn Petrini

Clinical Predictors of Occult Pneumonia in the Febrile Child

Charles G. Murphy MD
Background: The utility of chest radiographs (CXRs) for detecting occult pneumonia (OP) among pediatric patients without lower respiratory tract signs has been previously studied, but no predictors other than white blood cell count (WBC) and height of fever have been investigated. Objectives: To identify predictors of OP in pediatric patients in the postconjugate pneumococcal vaccination era. Methods: This was a retrospective cross sectional study that was conducted in a large urban pediatric hospital. Physician records of emergency department (ED) patients of age 10 years or less who presented with fever (,38░C) and had a CXR obtained for suspected pneumonia were reviewed. Patients were classified into two groups: "signs of pneumonia" and "no signs of pneumonia" on the basis of the presence or absence of respiratory distress, tachypnea, or lower respiratory tract findings. Occult pneumonia was defined as radiographic pneumonia in a patient without signs of pneumonia. Results: Two thousand one hundred twenty-eight patients were studied. Among patients categorized as having no signs of pneumonia (n = 1,084), 5.3% (95% CI = 4.0% to 6.8%) had OP. Presence of cough and longer duration of cough (greater than 10 days) had positive likelihood ratios (LR+) of 1.24 (95% CI = 1.15 to 1.33) and 2.25 (95% CI = 1.21 to 4.20), respectively. Absence of cough had a negative likelihood ratio (LR,) of 0.19 (95% CI = 0.05 to 0.75). The likelihood of OP increased with increasing duration of fever (LR+ for more than three days and more than five days of fever, respectively: 1.62; 95% CI = 1.13 to 2.31 and 2.24; 95% CI = 1.35 to 3.71). When obtained (56% of patients), WBC was a predictor of OP, with a LR+ of 1.76 (95% CI = 1.40 to 2.22) and 2.17 (95% CI = 1.58 to 2.96) for WBC of >15,000/mm3 and >20,000/mm3, respectively. Conclusions: Occult pneumonia was found in 5.3% of patients with fever and no lower respiratory tract findings, tachypnea, or respiratory distress. There is limited utility in obtaining a CXR in febrile children without cough. The likelihood of pneumonia increased with longer duration of cough or fever or in the presence of leukocytosis. [source]