Infection Mean Age Research Articles

915. Hepatitis A Burden of Disease and Associated Complications in Children and Adults in Mexico: A Retrospective Database Study from 2000-2019

BackgroundIn Mexico, Hepatitis A virus (HAV) infection is the leading cause of viral hepatitis in children, yet the pediatric HAV vaccine is not included in the national immunization program (NIP). Since 2013, 1-dose HAV vaccine is only given to infants of agricultural workers and in day-care centers. Mexico has intermediate HAV endemicity, yet the real burden of symptomatic HAV is unknown. The objective of this study is to describe the burden of HAV infection and severe complications in children and adults in Mexico.MethodsA retrospective database study was performed using the national surveillance system from all public health institutions in Mexico. Data on laboratory/clinically confirmed HAV cases, hospitalizations, and deaths, including for severe complications (Fulminant Hepatic Failure, Acute Liver Failure, Liver transplant), from 2000 to 2019 were analyzed (Table 1). Descriptive analyses were performed to estimate the disease burden and direct medical costs due to HAV per year for all ages, sex, and region. Table 1. Definition HAV-associated disease based on ICD-10 codes HAV, Hepatitis A Virus; ICD-10, International Classification of Diseases 10 Classification SystemResultsDuring the analysis period, the average annual incidence was 29.4 per 100,000 population (range: 43.0–10.9); the average hospitalization rate/year was 5.8% (range: 2.9%– 9.6%); and the average fatality rate/year was 0.44% (range: 0.23%–0.83%) (Figures 1a-b). Overall, there was a decreasing trend in HAV incidence over 2000–2017, with a recent increase in 2017–2019. As the incidence risk of HAV infection decreased, the mean age of infection increased. The biggest burden of HAV continued to be in children (1–9 years-old), yet there was an increase in incidence and hospitalizations (with complications) in older age groups (≥ 10–64 years-old) (Figures 2-3). The total direct medical costs (2019) due to HAV and related complications was estimated at &3.8 million Mexican pesos, which represented about 0.063% of total 2019 expenditure of the federal public budget for the health function. Figure 1. (a) Hospitalization rate (%) due to HAV infection by year in Mexico. (b) Fatality rate (%) due to HAV infection by year in Mexico. HAV, Hepatitis A Virus Figure 2. Incidence of HAV cases by age group and year in Mexico. HAV, Hepatitis A Virus; YoA, Years of Age Figure 3. Hospitalizations due to HAV infection and complications by age group and year in Mexico. HAV, Hepatitis A Virus; YoA, Years of Age ConclusionIn addition to Mexico’s intermediate HAV endemicity and improved sanitary conditions, these results describe an increase of HAV infection from children to adolescents/adults, which increases the risk for more severe and complicated disease and greater demand on healthcare resources. Our findings support the evidence for HAV vaccine inclusion in the NIP in Mexico.Disclosures Gerardo Luna-Casas, MD, The GSK Group of Companies (Scientific Research Study Investigator, Other Financial or Material Support, Company Owner (Estimatio SC)) Gilberto Sanchez-Gonzalez, PhD, The GSK Group of Companies (Scientific Research Study Investigator, Other Financial or Material Support, Company Owner (Estimatio SC)) Maria Yolanda Cervantes Apolinar, MD, The GSK Group of Companies (Employee, Shareholder) Gloria Huerta, MD, The GSK Group of Companies (Employee, Shareholder) Adriana Guzman Holst, MPH, The GSK Group of Companies (Employee)

Epidemiological and clinical features of cutaneous leishmaniasis and its time trend model in a high-endemic focus of disease in the southwest of Iran from 2014 to 2019.

Cutaneous leishmaniasis (CL) is a tropical infection with a relatively high incidence rate in Iran. The present study aimed to explore the time trend and associated factors of CL in Dezful, in southwest Iran. This case series study was conducted on all CL patients registered from 2014 to 2019. The descriptive analysis of the data was done using SPSS 20 software and the time series model on the number of cases was run through Interactive Time Series Modeling software. A total of 5349 leishmaniasis cases were identified in the study area during 2014-2019. The highest incidence rate was 35 840 per 100000 in 2014. The fitted time series model revealed a decreasing trend with an annual periodic pattern. The mean age of infection was 19.82y (standard deviation 21.87). The infection was most frequent in the 1-10y age group (41.7%). Also, females were more prone to leishmaniasis (54.7%). Most lesions were located on the hand (23.1%), face (19.7%), and forearm (17.75%) and 48.5% of patients had only one lesion. The results revealed a decreasing trend of leishmaniasis in Dezful. It has been predicted that this infection will reach a minimum rate (300 per 100000) in the winter of 2021.

EPIDEMIOLOGICAL CONSEQUENCES OF IMPERFECT VACCINES FOR IMMUNIZING INFECTIONS.

The control of some childhood diseases has proven to be difficult even in countries that maintain high vaccination coverage. This may be due to the use of imperfect vaccines and there has been much discussion on the different modes by which vaccines might fail. To understand the epidemiological implications of some of these different modes, we performed a systematic analysis of a model based on the standard SIR equations with a vaccinated component that permits vaccine failure in degree ("leakiness"), take ("all-or-nothingness") and duration (waning of vaccine-derived immunity). The model was first considered as a system of ordinary differential equations, then extended to a system of partial differential equations to accommodate age structure. We derived analytic expressions for the steady states of the system and the final age distributions in the case of homogenous contact rates. The stability of these equilibria are determined by a threshold parameter Rp , a function of the vaccine failure parameters and the coverage p. The value of p for which Rp = 1 yields the critical vaccination ratio, a measure of herd immunity. Using this concept we can compare vaccines that confer the same level of herd immunity to the population but may fail at the individual level in different ways. For any fixed Rp > 1, the leaky model results in the highest prevalence of infection, while the all-or-nothing and waning models have the same steady state prevalence. The actual composition of a vaccine cannot be determined on the basis of steady state levels alone, however the distinctions can be made by looking at transient dynamics (such as after the onset of vaccination), the mean age of infection, the age distributions at steady state of the infected class, and the effect of age-specific contact rates.

Human Metapneumovirus

On the basis of strong research evidence and consensus, (1) (2) (3) (4) human metapneumovirus is a leading cause of upper and lower respiratory tract infections in children. On the basis of research evidence and consensus, (3) (5) (6) (7) the clinical features of MPV-associated disease are similar to those of RSV. MPV is an important cause of asthma exacerbations, bronchiolitis, and pneumonia. Bacterial superinfection can occur.On the basis of research evidence and consensus, (2) (3) (8) the mean age of infection is 6 to 12 months, and nearly all school-age children are seropositive. However, infection can recur, likely in part due to impaired CD8+ T-cell response. On the basis of research evidence and consensus, (9) (10) (11) morbidity and mortality are the highest in patients who are premature, are immunosuppressed, or have underlying cardiopulmonary abnormalities. On the basis of research evidence and consensus, (2) commercially available diagnostic tests exist, and reverse transcriptase–PCR is the most commonly used. On the basis of consensus, because of a lack of relevant clinical studies, recombinant virus vaccines and monoclonal antibodies may be useful as prophylactics or therapeutics. (10)

Symptomatic Versus Inapparent Outcome in Repeat Dengue Virus Infections Is Influenced by the Time Interval between Infections and Study Year

Four dengue virus serotypes (DENV1-4) circulate globally, causing more human illness than any other arthropod-borne virus. Dengue can present as a range of clinical manifestations from undifferentiated fever to Dengue Fever to severe, life-threatening syndromes. However, most DENV infections are inapparent. Yet, little is known about determinants of inapparent versus symptomatic DENV infection outcome. Here, we analyzed over 2,000 DENV infections from 2004 to 2011 in a prospective pediatric cohort study in Managua, Nicaragua. Symptomatic cases were captured at the study health center, and paired healthy annual samples were examined on a yearly basis using serological methods to identify inapparent DENV infections. Overall, inapparent and symptomatic DENV infections were equally distributed by sex. The mean age of infection was 1.2 years higher for symptomatic DENV infections as compared to inapparent infections. Although inapparent versus symptomatic outcome did not differ by infection number (first, second or third/post-second DENV infections), substantial variation in the proportion of symptomatic DENV infections among all DENV infections was observed across study years. In participants with repeat DENV infections, the time interval between a first inapparent DENV infection and a second inapparent infection was significantly shorter than the interval between a first inapparent and a second symptomatic infection. This difference was not observed in subsequent infections. This result was confirmed using two different serological techniques that measure total anti-DENV antibodies and serotype-specific neutralizing antibodies, respectively. Taken together, these findings show that, in this study, age, study year and time interval between consecutive DENV infections influence inapparent versus symptomatic infection outcome, while sex and infection number had no significant effect. Moreover, these results suggest that the window of cross-protection induced by a first infection with DENV against a second symptomatic infection is approximately 2 years. These findings are important for modeling dengue epidemics and development of vaccines.

Model-based projections of the population-level impact of hepatitis A vaccination in Mexico

There are indications of a shift in the pattern of hepatitis A (HAV) in Mexico from high to intermediate endemicity, progressively increasing the mean age of infection and the proportion of cases which are symptomatic. This study estimated the potential impact of universal infant HAV vaccination in Mexico with two doses of Havrix™ at 12 and 18 mo of age on all HAV infections and symptomatic HAV infections. We developed a dynamic transmission model that accounts for changes in demography and HAV epidemiology. It was calibrated using Mexican age-specific seroprevalence and symptomatic HAV incidence data. With 70% first-dose coverage and 85% second-dose coverage, the calibrated model projected that HAV vaccination would reduce the incidence of all HAV infections (symptomatic and asymptomatic) after the first 25 y of vaccination by 71–76% (minimum and maximum for different transmission scenarios). The projected reduction in cumulative incidence of symptomatic HAV infections over the first 25 y of vaccination was 45–51%. With 90% first-dose coverage and 85% second-dose coverage, the projected reduction in incidence of all HAV infections was 85–93%, and the projected reduction in the cumulative incidence of symptomatic HAV infections was 61–67%, over a 25-y time frame. Sensitivity analyses indicated that second-dose coverage is important under the conservative base-case assumptions made about the duration of vaccine protection. The model indicated that universal infant HAV vaccination could substantially reduce the burden of HAV disease in Mexico.

Seroprevalence of varicella zoster virus among pregnant women in Hong Kong: Comparison with self-reported history

To compare seroprevalence (serum IgG titre) with self-reported history of varicella zoster virus (VZV) infection among pregnant women in Hong Kong. Pregnant women undergoing first trimester Down screening over a 3-months period were recruited for the study. Positive immunity was found in 477 (95.4%) of the 500 recruited women, and those with positive, negative, or uncertain history of infection had similarly high seroprevalence (96.4, 90.5, 95.9% respectively). The mean age of infection from self-recalled history was 8.61 (SD 4.69) years, and only 3% recalled infection after age 18. Insufficient knowledge on the disease and vaccination was demonstrated. Despite the absence of a routine vaccination programme, VZV immunity was high among pregnant women, the majority being infected during childhood and infection above age 18 was very rare. Hence, universal antenatal screening or vaccination for all women in the reproductive age would not be cost-effective in Hong Kong.

Development of the Activity Effort Scale for Women Aging With Paralytic Polio

The purpose of this study was to develop and psychometrically test the Activity Effort Scale among women aging with the affects of paralytic polio. On the basis of prior qualitative research, six items were generated. Two researchers with expertise in disability were consulted for examination of the items, which led to the addition of two more items to the scale. Next, a survey was sent to 500 women with a history of paralytic polio. Data from participants were subjected to psychometric testing: factor analysis, reliability testing, and correlation with existing measures. Useable surveys were returned by 299 women aged 49 to 75 years. Mean age of infection with polio was 7.6 years, and 54% had spinal polio. Principal component analysis of the 8-item scale resulted in one component with an eigenvalue above 1, explaining 74% of the variance. The Cronbach's alpha was .92. Correlations between variables supported content validity. Data suggest that the Activity Effort Scale is a valid and reliable tool consisting of one component measuring frequency of effort exerted beyond levels of discomfort, pain, and fatigue among women aging with paralytic polio.

Identification of potential candidates for varicella vaccination by history: questionnaire and seroprevalence study

Guidance from the Joint Committee on Vaccination and Immunisation regarding varicella vaccination of workers in healthcare settings is imminent.1 The new recommendations will advise that all those with a negative...

Nine-year follow-up of hepatitis C virus infection in a rural area of Hebei province, China

To investigate natural history of hepatitis C virus infection and related factors among plasma donors in China. 172 plasma donors in a rural area of Hebei province had been diagnosed as HCV infection in 1993. No antiviral treatment was applied to them during the period of infection. In the present study, we investigated the outcome of HCV infection nine years later and related factors affecting the outcome. In fact, only 142 cases were followed up in the investigation. The mean age of 142 cases of blood donors was 46 +/- 9 and the mean age of infection was 37 +/- 9 years old. After nine-year follow-up, 1.2% died of end-stage liver disease. 130 (91.6%) of 142 cases under investigation were still positive for HCV RNA or anti-HCV in their blood and 12 cases (8.4%) were negative for both HCV RNA and anti-HCV. 3.1% developed liver cirrhosis among the patients with persistent infection. The mean level of ALT, AST, GGT among HCV RNA positive cases were significantly higher than that of HCV RNA negative cases (P < 0.001). The abnormal rates of ALT and/or AST in male patients were significantly higher than those of female patients (P = 0.005). The rate of progression to liver cirrhosis from chronic hepatitis C virus was significantly higher in patients co-infected with HCV/HBV than that of the cases of single HCV infection. Higher chronic rate was observed in this research. Superinfection of HBV/HCV may have worse clinical outcomes.

The epidemiology of hepatitis A infection in Palestine: a universal vaccination programme is not yet needed.

In Palestine, there has been an increase in the reported incidence of acute hepatitis A virus (HAV) infection since 1995. Since overt clinical disease occurs only among adults, questions were raised whether or not a shift in the epidemiology of HAV has occurred. This is generally characterized by a decrease in the overall incidence rate and a shifting in the mean age of infection towards adolescence and early adulthood. The need for a vaccination programme is being discussed. To resolve this issue, we examined the prevalence of anti-HAV in a representative sample of 396 school children in the Gaza Strip. The prevalence of anti-HAV was 93.7% (95% CI: 91.3, 96.1%). Stratifying the prevalence by age showed that 87.8% (95% CI: 78.6, 97%) were HAV antibody positive by the age of 6. By the age of 14, almost 98% (95% CI: 92.7, 100%) were HAV antibody positive. This means that the majority of HAV infection is still taking place in early childhood, when it is usually asymptomatic and of little clinical significance. The results refuted the shifting epidemiology theory and we recommend that a vaccination programme against HAV infection is not yet needed. Alternative explanations for the increase in reported cases are discussed.

Immunosurveillance and the evaluation of national immunization programmes: a population-based approach.

Mass vaccination can change the epidemiological dynamics of infectious diseases. It may result in a limited persistence of natural and vaccine-induced immunity and a higher mean age of infection, which may lead to a greater risk of complications. The epidemiological situation should be monitored and immunosurveillance based on the assessment of specific antibodies against vaccine-preventable diseases in human serum is one of the tools. In order to estimate the immunity of the Dutch population reliably, a large-scale, population-based, collection of serum samples was established (8359 sera in a nation-wide sampling and 1589 sera from municipalities with low vaccine coverage). In contrast to collecting residual sera from laboratories, this approach gains extensive information by means of a questionnaire regarding the determinants of the immune status and the risk factors for the transmission of infectious diseases in general. The population-based approach gives a better guarantee that the data are representative than collecting sera from laboratories does.

AIDS and HIV infection in Uganda—are more women infected than men?

In countries in sub-Saharan Africa, HIV is transmitted primarily heterosexually. HIV infection and AIDS in women not only affects women's health but also has implications for the other members of society. Maternal infection is the source of most childhood HIV infection in Africa and maternal health is a strong predictor of child survival. In Uganda, a review of passive AIDS surveillance has shown almost equal numbers of clinical cases reported in men and women. However, in three population-based HIV serosurveys, women were consistently found to have a higher infection rate (approximately 1.4 times) than men. In addition, both AIDS case surveillance and seroprevalence studies demonstrate an earlier age of presentation and mean age of infection in women. The higher rate of HIV infection in women suggests either differential rates of transmission between women and men, higher rates of female sexual exposure to infected men, or longer survival among HIV-infected women compared with men. Although further studies are required to illuminate both the biology and the epidemiology of heterosexual HIV transmission in Africa, these findings of earlier and higher infection rates in women have important implications for women's health and child survival in Uganda and indicate the need for specially targeted interventions to reduce transmission in this group.

Radiological diagnosis of neurocysticercosis

Cysticercosis, once thought to be confined to discrete geographical areas, such as Central America and Central Europe, is now increasingly recognized in many other parts of the world. In the USAthere has been a dramatic increase in the number of cases found, especially in those states where there is a large population of migrants from Mexico or Central America I. As new imaging techniques such as X-ray Computed Tomography (XRCT) and Magnetic Res-onance Computed Tomography (MRCT), are employed in endemic areas, our concept of the disease is changing. It seems for example, that the mean age of infection may be younger than previously thought, and cysticercosis is becoming recognized as a prevalent pediatric disease in developing countries (see Box I ). The development of XRCT and MRCT (Box 2) has greatly facilitated the diagnosis of neurocysticercosis; in conjunction with the clinical picture and serological studies of blood and spinal fluid, they now offer a high degree of accur-acy in diagnosis 3. Human infection with adult tapeworms of Taenia solium is usually associated with only minor symptoms, but infection with oncospheres developing cysticerci, can produce severe, even life-threatening disFig. 2, Intraventricular Cyst, this form does not