Your search found 18 Results
Journal of Human Lactation. 2017 Feb; 33(1):140-148.BACKGROUND: Extended breastfeeding duration is common in India. Extended breastfeeding protects the infant from infectious disease and promotes child spacing. In the 1990s, the median breastfeeding duration in India was 24 months. Research aim: This study aimed to investigate the median duration of breastfeeding in India and to identify the factors associated with extended breastfeeding to 24 months as recommended by the World Health Organization. METHODS: This cross-sectional data analysis used nationally representative data from the 2011-2012 Indian Human Development Survey II. The outcome in this study was extended breastfeeding defined as breastfeeding to 24 months or more. Multivariate logistic regression was used to identify the factors associated with extended breastfeeding. RESULTS: The median duration of breastfeeding was 12 months; approximately 25% of women breastfed 24 months or more. Women were at greater odds of breastfeeding 24 months or more if the infant was a boy compared with a girl, if the women lived in a rural area compared with an urban area, if the women were married at a young age (< 17 vs. 20 years or older at marriage), and if the delivery was assisted by a friend or relative compared with a doctor. CONCLUSION: The median duration of breastfeeding has decreased by 50% from 1992-1993 to 2011-2012. The women who continue to breastfeed 24 months or more tend to be more traditional (i.e., living in rural areas, marrying young, and having family/friends as birth attendants). Further research to study the health effect of decreased breastfeeding duration is warranted.
Tropical Medicine and International Health. 2012 Jun; 17(6):760-6.OBJECTIVE: To review the activities, progress, achievements and challenges of the Zambia Ministry of Health tuberculosis (TB)/HIV collaborative activities over the past decade. METHODS: Analysis of Zambia Ministry of Health National TB and HIV programme documents and external independent programme review reports pertaining to 2000-2010. RESULTS: The number of people testing for HIV increased from 37 557 persons in 2003 to 1 327 995 persons in 2010 nationally. Those receiving anti-retroviral therapy (ART) increased from 143 in 2003 to 344 304 in 2010. The national HIV prevalence estimates declined from 14.3% in 2001 to 13.5% in 2009. The proportion of TB patients being tested for HIV increased from 22.6% in 2006 to 84% in 2010 and approximately 70% were HIV positive. The proportion of the HIV-infected TB patients who: (i) started on ART increased from 38% in 2006 to 50% in 2010; (ii) commenced co-trimoxazole preventive therapy (CPT) increased from 31% in 2006 to 70% in 2010; and (iii) were successfully treated increased to an average of 80% resulting in decline of deaths from 13% in 2006 to 9% in 2010. CONCLUSIONS: The scale-up of TB/HIV collaborative programme activities in Zambia has steadily increased over the past decade resulting in increased testing for TB and HIV, and anti-retroviral (ARV) rollout with improved treatment outcomes among TB patients co-infected with HIV. Getting service delivery points to adhere to WHO guidelines for collaborative TB/HIV activities remains problematic, especially those meant to reduce the burden of TB in people living with HIV/AIDS (PLWHA). (c) 2012 Blackwell Publishing Ltd.
The impact of the new WHO antiretroviral treatment guidelines on HIV epidemic dynamics and cost in South Africa.
PloS One. 2011; 6(7):e21919.BACKGROUND: Since November 2009, WHO recommends that adults infected with HIV should initiate antiretroviral therapy (ART) at CD4+ cell counts of =350 cells/microl rather than =200 cells/microl. South Africa decided to adopt this strategy for pregnant and TB co-infected patients only. We estimated the impact of fully adopting the new WHO guidelines on HIV epidemic dynamics and associated costs. METHODS AND FINDING: We used an established model of the transmission and control of HIV in specified sexual networks and healthcare settings. We quantified the model to represent Hlabisa subdistrict, KwaZulu-Natal, South Africa. We predicted the HIV epidemic dynamics, number on ART and program costs under the new guidelines relative to treating patients at =200 cells/microl for the next 30 years. During the first five years, the new WHO treatment guidelines require about 7% extra annual investments, whereas 28% more patients receive treatment. Furthermore, there will be a more profound impact on HIV incidence, leading to relatively less annual costs after seven years. The resulting cumulative net costs reach a break-even point after on average 16 years. CONCLUSIONS: Our study strengthens the WHO recommendation of starting ART at =350 cells/microl for all HIV-infected patients. Apart from the benefits associated with many life-years saved, a modest frontloading appears to lead to net savings within a limited time-horizon. This finding is robust to alternative assumptions and foreseeable changes in ART prices and effectiveness. Therefore, South Africa should aim at rapidly expanding its healthcare infrastructure to fully embrace the new WHO guidelines.
[Clinical, epidemiological and microbiological characteristics of a cohort of pulmonary tuberculosis patients in Cali, Colombia] Caracteristicas clinicas, epidemiologicas y microbiologicas de una cohorte de pacientes con tuberculosis pulmonar en Cali, Colombia.
Biomedica. 2010 Oct-Dec; 30(4):482-91.INTRODUCTION: The World Health Organization recommended strategy for global tuberculosis control is a short-course, clinically administered treatment, This approach has approximately 70% coverage in Colombia. OBJECTIVE: The clinical, epidemiological and microbiological characteristics along with drug therapy outcomes were described in newly diagnosed, pulmonary tuberculosis patients. MATERIALS AND METHODS: This was a descriptive study, conducted as part of a multicenter clinical trial of tuberculosis treatment. A cohort of 106 patients with pulmonary tuberculosis were recruited from several public health facilities in Cali between April 2005 and June 2006. Sputum smear microscopy, culture, drug susceptibility tests to first-line anti-tuberculosis drugs, chest X- ray and HIV-ELISA were performed. Clinical and epidemiological information was collected for each participant. Treatment was administered by the local tuberculosis health facility. Food and transportation incentives were provided during a 30 month follow-up period. RESULTS: The majority of patients were young males with a diagnostic delay longer than 9 weeks and a high sputum smear grade (2+ or 3+). The initial drug resistance was 7.5% for single drug treatment and 1.9% for multidrug treatments. The incidence of adverse events associated with treatment was 8.5%. HIV co-infection was present in 5.7% of the cases. Eighty-six percent of the patients completed the treatment and were considered cured. The radiographic presentation varied within a broad range and differed from the classic progression to cavity formation. CONCLUSION: Delay in tuberculosis diagnosis was identified as a risk factor for treatment compliance failure. The study population had similar baseline epidemiologic characteristics to those described in other cohort studies.
Wei Sheng Yan Jiu. 2007 Mar; 36(2):203-6.OBJECTIVE: To compare children's growth patterns and estimates of malnutrition using the WHO standards versus the NCHS reference in China. METHODS: Data originated from China children nutrition surveillance in 2005, Z-scores and prevalence of malnutrition were compared between standards. RESULTS: There was substantial difference in Z-scores between standards in rural (P < 0.0001). According to the WHO standards, prevalence of underweight in rural was lower than that of underweight based on the NCHS reference (6.1% . vs. 8.6%, P < 0.0001). Except for children under 6 months, all age groups underweight rates were lower according to the WHO standards. Prevalence of stunting in rural was higher based on the WHO standards (16.3% . vs. 13.0%, P < 0.0001), prevalences of stunting under 6 months were 2.1 times of that based on NCHS reference. As for wasting, there were no differences between standards, but wasting was substantially higher during the first half of infancy. Overweight rates based on the WHO standards were higher than those based on NCHS reference in urban (6.7% . vs. 5.4%, P < 0.0001). CONCLUSION: In comparison with NCHS reference, population estimates of malnutrition would vary by age, growth indicator based on WHO standards. The WHO standards could provide a better tool to monitor the rapid and changing rate of growth in early infancy, further analysis on existing data was needed.
[Implementation of the Integrated Management of Childhood Illnesses strategy in Northeastern Brazil] Implementacao da estrategia Atencao Integrada as Doencas Prevalentes na Infancia no Nordeste, Brasil.
Revista De Saude Publica. 2008 Aug; 42(4):598-606.OBJECTIVE: The majority of child deaths are avoidable. The Integrated Management of Childhood Illnesses strategy, developed by the World Health Organization and the United Nations Children's Fund, aims to reduce child mortality by means of actions to improve performance of health professionals, the health system organization, and family and community practices. The article aimed to describe factors associated with the implementation of this strategy in three states of Northeastern Brazil. METHODS: Ecological study conducted in 443 municipalities in the states of Northeastern Brazil Ceara, Paraiba and Pernambuco, in 2006. The distribution of economic, geographic, environmental, nutritional, health service organization, and child mortality independent variables were compared between municipalities with and without the strategy. These factors were assessed by means of a hierarchical model, where Poisson regression was used to calculate the prevalence ratios, after adjustment of confounding factors. RESULTS: A total of 54% of the municipalities studied had the strategy: in the state of Ceara, 65 had it and 43 did not have it; in the state of Paraiba, 27 had it and 21 did not have it; and in the state of Pernambuco, 147 had it and 140 did not have it. After controlling for confounding factors, the following variables were found to be significantly associated with the absence of the strategy: lower human development index, smaller population, and greater distance from the capital. CONCLUSIONS: There was inequality in the development of the strategy, as municipalities with a higher risk to child health showed lower rates of implementation of actions. Health policies are necessary to help this strategy to be consolidated in the municipalities that are at a higher risk of child mortality.
PloS One. 2010; 5(1):e8796.BACKGROUND: The tight epidemiological coupling between HIV and its associated opportunistic infections leads to challenges and opportunities for disease surveillance. METHODOLOGY/PRINCIPAL FINDINGS: We review efforts of WHO and collaborating agencies to track and fight the TB/HIV co-epidemic, and discuss modeling--via mathematical, statistical, and computational approaches--as a means to identify disease indicators designed to integrate data from linked diseases in order to characterize how co-epidemics change in time and space. We present R(TB/HIV), an index comparing changes in TB incidence relative to HIV prevalence, and use it to identify those sub-Saharan African countries with outlier TB/HIV dynamics. R(TB/HIV) can also be used to predict epidemiological trends, investigate the coherency of reported trends, and cross-check the anticipated impact of public health interventions. Identifying the cause(s) responsible for anomalous R(TB/HIV) values can reveal information crucial to the management of public health. CONCLUSIONS/SIGNIFICANCE: We frame our suggestions for integrating and analyzing co-epidemic data within the context of global disease monitoring. Used routinely, joint disease indicators such as R(TB/HIV) could greatly enhance the monitoring and evaluation of public health programs.
Epidemiology and clinical features of pneumonia according to radiographic findings in Gambian children.
Tropical Medicine and International Health. 2007 Nov; 12(11):1377-1385.The objective was to assess the effect of vaccines against pneumonia in Gambian children. Data from a randomized, controlled trial of a 9-valent pneumococcal conjugate vaccine (PCV) were used. Radiographic findings, interpreted using WHO definitions, were classified as primary end point pneumonia, 'other infiltrates / abnormalities' pneumonia and pneumonia with no abnormality. We calculated the incidence of the different types of radiological pneumonia, and compared clinical and laboratory features between these groups. Among children who did not receive PCV, the incidence of pneumonia with no radiographic abnormality was about twice that of 'other infiltrates' pneumonia and three times that of primary endpoint pneumonia. Most respiratory symptoms, reduced feeding and vomiting occurred most frequently in children with primary endpoint pneumonia. These children were more likely to be malnourished, to have bronchial breath sounds or invasive bacterial diseases, and to die within 28 days of consultation than children in the other groups. Conversely, a history of convulsion, diarrhoea or fast breathing, malaria parasitaemia and isolation of salmonellae were commoner in children with pneumonia with no radiographic abnormality. Lower chest wall indrawing and rhonchi on auscultation were seen most frequently in children with 'other infiltrates / abnormalities' pneumonia. Primary endpoint pneumonia is strongly associated with bacterial aetiology and severe pneumonia. Since this category of pneumonia is significantly reduced after vaccination with Hib and pneumococcal vaccines, the risk-benefit of antimicrobial prescription for clinical pneumonia for children with increased respiratory rate may warrant re-examination once these vaccines are in widespread use. (author's)
Bulletin of the World Health Organization. 2007 Aug; 85(8):586-592.WHO's new Global Plan to Stop TB 2006-2015 advises countries with a high burden of tuberculosis (TB) to expand case-finding in the private sector as well as services for patients with HIV and multidrug-resistant TB (MDR-TB). The objective of this study was to evaluate these strategies in Thailand using data from the Thailand TB Active Surveillance Network, a demonstration project begun in 2004. In October 2004, we began contacting public and private health-care facilities monthly to record data about people diagnosed with TB, assist with patient care, provide HIV counselling and testing, and obtain sputum samples for culture and susceptibility testing. The catchment area included 3.6 million people in four provinces. We compared results from October 2004-September 2005 (referred to as 2005) to baseline data from October 2002-September 2003 (referred to as 2003). In 2005, we ascertained 5841 TB cases (164/100 000), including 2320 new smear-positive cases (65/100 000). Compared with routine passive surveillance in 2003, active surveillance increased reporting of all TB cases by 19% and of new smear-positive cases by 13%. Private facilities diagnosed 634 (11%) of all TB cases. In 2005, 1392 (24%) cases were known to be HIV positive. The proportion of cases with an unknown HIV status decreased from 66% (3226/4904) in 2003 to 23% (1329/5841) in 2005 (P< 0.01). Of 4656 pulmonary cases, mycobacterial culture was performed in 3024 (65%) and MDR-TB diagnosed in 60 (1%). In Thailand, piloting the new WHO strategy increased case-finding and collaboration with the private sector, and improved HIV services for TB patients and the diagnosis of MDR-TB. Further analysis of treatment outcomes and costs is needed to assess this programme's impact and cost effectiveness. (author's)
Epidemiology of antituberculosis drug resistance (the Global Project on Anti-tuberculosis Drug Resistance Surveillance): an updated analysis.
Lancet. 2006 Dec 16; 368(9553):2142-2154.The burden of tuberculosis is compounded by drug-resistant forms of the disease. This study aimed to analyse data on antituberculosis drug resistance gathered by the WHO and International Union Against Tuberculosis and Lung Disease Global Project on Anti-tuberculosis Drug Resistance Surveillance. Data on drug susceptibility testing for four antituberculosis drugs--isoniazid, rifampicin, ethambutol, and streptomycin--were gathered in the third round of the Global Project (1999-2002) from surveys or ongoing surveillance in 79 countries or geographical settings. These data were combined with those from the first two rounds of the project and analyses were done. Countries that participated followed a standardised set of guidelines to ensure comparability both between and within countries. The median prevalence of resistance to any of the four antituberculosis drugs in new cases of tuberculosis identified in 76 countries or geographical settings was 10.2% (range 0.0-57.1). The median prevalence of multidrug resistance in new cases was 1.0% (range 0.0-14.2). Kazakhstan, Tomsk Oblast (Russia), Karakalpakstan (Uzbekistan), Estonia, Israel, the Chinese provinces Liaoning and Henan, Lithuania, and Latvia reported prevalence of multidrug resistance above 6.5%. Trend analysis showed a significant increase in the prevalence of multidrug resistance in new cases in Tomsk Oblast (p < 0.0001). Hong Kong (p = 0.01) and the USA (p = 0.0002) reported significant decreasing trends in multidrug resistance in new cases of tuberculosis. Multidrug resistance represents a serious challenge for tuberculosis control in countries of the former Soviet Union and in some provinces of China. Gaps in coverage of the Global Project are substantial, and baseline information is urgently required from several countries with high tuberculosis burden to develop appropriate control interventions. (author's)
Potential impact of antiretroviral therapy on HIV-1 transmission and AIDS mortality in resource-limited settings.
Journal of Acquired Immune Deficiency Syndromes. 2006 Apr 15; 41(5):632-641.The objective was to estimate the potential impact of antiretroviral therapy on the heterosexual spread of HIV-1 infection and AIDS mortality in resource-limited settings. A mathematic model of HIV-1 disease progression and transmission was used to assess epidemiologic outcomes under different scenarios of antiretroviral therapy, including implementation of World Health Organization guidelines. Implementing antiretroviral therapy at 5% HIV-1 prevalence and administering it to 100% of AIDS cases are predicted to decrease new HIV-1 infections and cumulative deaths from AIDS after 10 years by 11.2% (inter-quartile range [IQR]: 1.8%-21.4%) and 33.4% (IQR: 26%-42.8%), respectively. Later implementation of therapy at endemic equilibrium (40% prevalence) is predicted to be less effective, decreasing new HIV-1 infections and cumulative deaths from AIDS by 10.5% (IQR: 2.6%-19.3%) and 27.6% (IQR: 20.8%-36.8%), respectively. Therapy is predicted to benefit the infected individual and the uninfected community by decreasing transmission and AIDS deaths. The community benefit is greater than the individual benefit after 25 years of treatment and increases with the proportion of AIDS cases treated. Antiretroviral therapy is predicted to have individual and public health benefits that increase with time and the proportion of infected persons treated. The impact of therapy is greater when introduced earlier in an epidemic, but the benefit can be lost by residual infectivity or disease progression on treatment and by sexual disinhibition of the general population. (author's)
American Journal of Tropical Medicine and Hygiene. 2006 Feb; 74(2):187-188.Accurate measurement of malaria incidence is of great importance to malaria control, but it is very hard to achieve in most circumstances. Robert Snow and colleagues recently reported the results of a method to determine the case incidences of Plasmodium falciparum malaria around the world. For non-African P. falciparum malaria, they estimated three times more cases than in recent WHO figures. They suggested that the WHO estimates were lower due to the use of passively reported national malaria records. We, who prepared the WHO estimates of non-African malaria cases and published the method used to derive them, discuss here the suggestion by Snow and colleagues that, because of the data and methods used, the WHO estimates must be an under-representation of the true incidence of malaria cases. (excerpt)
Facilitating the WHO Expanded Program of Immunization: the clinical profile of a combined diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b vaccine.
International Journal of Infectious Diseases. 2003 Jun; 7(2):143-151.Background: Vaccines are important weapons in the fight against infectious diseases. The World Health Organization (WHO) Expanded Program on Immunization (EPI) has been extended to include recommendations for hepatitis B and Haemophilus influenzae type b (Hib) vaccinations. The WHO has recommended that combined vaccines be used where possible, to reduce the logistic costs of vaccine delivery. This paper reviews the efficacy, safety and cost-effectiveness of Tritanrix-HB/Hib, the only commercially available combined diphtheria, tetanus, whole cell pertussis, hepatitis B and conjugated Hib vaccine. Methods: The immunogenicity and reactogenicity results of five published clinical trials involving Tritanix-HB/Hib in a variety of immunization schedules and countries were reviewed. Based on these data and cost-effectiveness studies, an assessment of its suitability for use in national immunization programs was made. Results: Tritanix-HB/Hib has shown excellent immunogenicity in clinical trials using a variety of schedules, with no reduced immunogenicity observed for any of the components of the combined vaccine. It has similar reactogenicity to DTPw vaccines alone. Pharmacoeconomic analyses have shown combined DTP-HB/Hib vaccines to be cost-effective compared to separate vaccines. Conclusions: Replacement of DTPw vaccination by Tritanrix-HB/Hib can be done without modifying the existing national immunization programs. This should facilitate widespread coverage of hepatitis B and Hib vaccinations and their rapid incorporation into the EPI. (author's)
Inconsistencies between tuberculosis reporting by the Ministry of Health and the World Health Organization. Mexico, 1981-1998. Discrepancias entre los datos ofrecidos por la Secretaría de Salud y la Organización Mundial de la Salud sobre tuberculosis en México, 1981-1998.
Salud Pública de México. 2003 Mar-Apr; 45(2):78-83.The objective was to describe the tuberculosis morbidity and mortality trends in Mexico, by comparing the data reported by the Ministry of Health (MH) and the World Health Organization (WHO) between 1981 and 1998. The number of cases notified in the past few years, their rates, and the trends of the disease in Mexico were analyzed. The incidence of smear-positive pulmonary tuberculosis was estimated for 1997 and 1998 with the annual tuberculosis infection risk (ATIR), to estimate the percentage of bacilliferous cases in 1997-1998. WHO reported more tuberculosis cases for Mexico than the MH. However, this difference has decreased throughout the years. The notification of smear-positive cases remained stable during 1993-1998. The estimated percentages of detection were 66% for 1997 and 26% for 1998 (based on ATIR of 0.5%). Tuberculosis mortality decreased gradually (6.7% per year) between 1990 and 1998, whereas the number of new cases increased, suggesting the persistence of disease transmission in the population. Inconsistencies between case notifications from national data and WHO were considerable, but decreased progressively during the study period. According to ATIR estimations, a considerable number of infectious tuberculosis cases are not detected. (author's)
Emerging Infectious Diseases. 1998 Jul-Sep; 4(3):398-403.A recent upsurge of malaria in endemic-disease areas with explosive epidemics in many parts of Africa is probably caused by many factors, including rapidly spreading resistance to antimalarial drugs, climatic changes, and population movements. In Africa, malaria is caused by Plasmodium falciparum and is transmitted by Anopheles gambiae complex. Control efforts have been piecemeal and not coordinated. Strategies for control should have a solid research base both for developing antimalarial drugs and vaccines and for better understanding the pathogenesis, vector dynamics, epidemiology, and socioeconomic aspects of the disease. An international collaborative approach is needed to build appropriate research in a national context and to effectively translate research results into practical applications in the field. The Multilateral Initiative for Malaria in Africa can combine all of the above strategies to plan and coordinate partnerships, networking, and innovative approaches between African scientists and their Northern partners. (author's)
American Journal of Clinical Nutrition. 2003 Aug; 78(2):291-295.Background: Opinions and recommendations about the optimal duration of exclusive breastfeeding have been strongly divided, but few published studies have provided direct evidence on the relative risks and benefits of different breastfeeding durations in recipient infants. Objective: We examined the effects on infant growth and health of 3 compared with 6 mo of exclusive breastfeeding. Design: We conducted an observational cohort study nested within a large randomized trial in Belarus by comparing 2862 infants exclusively breastfed for 3 mo (with continued mixed breastfeeding through = 6 mo) with 621 infants who were exclusively breastfed for = 6 mo. Regression to the mean, within-cluster correlation, and cluster- and individual-level confounding variables were accounted for by using multilevel regression analyses. Results: From 3 to 6 mo, weight gain was slightly greater in the 3-mo group [difference: 29 g/mo (95% CI: 13, 45 g/mo)], as was length gain [difference: 1.1 mm (0.5, 1.6 mm)], but the 6-mo group had a faster length gain from 9 to 12 mo [difference: 0.9 mm/mo (0.3, 1.5 mm/mo)] and a larger head circumference at 12 mo [difference: 0.19 cm (0.07, 0.31 cm)]. A significant reduction in the incidence density of gastrointestinal infection was observed during the period from 3 to 6 mo in the 6-mo group [adjusted incidence density ratio: 0.35 (0.13, 0.96)], but no significant differences in risk of respiratory infectious outcomes or atopic eczema were apparent. Conclusions: Exclusive breastfeeding for 6 mo is associated with a lower risk of gastrointestinal infection and no demonstrable adverse health effects in the first year of life. (author's)
Importation and circulation of poliovirus in Bulgaria in 2001. [Importation et circulation du poliovirus en Bulgarie en 2001]
Bulletin of the World Health Organization. 2003 Jul; 81(7):476-481.Objective: To characterize the circumstances in which poliomyelitis occurred among three children in Bulgaria during 2001 and to describe the public health response. Methods: Bulgarian authorities investigated the three cases of polio and their contacts, conducted faecal and serological screening of children from high-risk groups, implemented enhanced surveillance for acute flaccid paralysis, and conducted supplemental immunization activities. Findings: The three cases of polio studied had not been vaccinated and lived in socioeconomically deprived areas of two cities. Four Roma children from the Bourgas district had antibody titres to serotype 1 poliovirus only, and wild type 1 virus was isolated from the faeces of two asymptomatic Roma children in the Bourgas and Sofia districts. Poliovirus isolates were related genetically and represented a single evolutionary lineage; genomic sequences were less than 90% identical to poliovirus strains isolated previously in Europe, but 98.3% similar to a strain isolated in India in 2000. No cases or wild virus isolates were found after supplemental immunization activities were launched in May 2001. Conclusions: In Bulgaria, an imported poliovirus was able to circulate for two to five months among minority populations. Surveillance data strongly suggest that wild poliovirus circulation ceased shortly after supplemental immunization activities with oral poliovirus vaccine were conducted. (author's)
Journal of Viral Hepatitis. 2003 Mar; 10(2):141-149.Hepatitis B (HB) is thought to be an expanding health problem in Russia. The incidence of infection was estimated from mandatorily reported HB cases in St Petersburg. The two-sided t-test for independent samples and the LOESS (locally-weighted regression) smoother were used to compare the age at infection for symptomatic, asymptomatic and chronic infections, by gender. The force of infection was estimated from seroprevalence data (907 sera taken in 1999) using a newly developed nonparametric method based on local polynomials, as well as an earlier method based on isotonic regression and kernel smoothers. With the local polynomial method, pointwise confidence intervals (95%) were constructed by bootstrapping. On average, men contracted HB infection at a significantly younger age than women (in 1999, 21.8 vs 22.7 years, respectively). The overall male to female ratio was 1.92. In 1999 the overall incidence almost doubled compared with the preceding years and tripled among the age groups with highest incidence (15–29-year olds: 85% of cases in 1999). The incidence increase was associated with a lower average age at infection (24.1 years in 1994 vs 22.1 years in 1999). The age and gender-specific force of infection estimates generally confirmed the incidence estimates and emphasized the usefulness of local polynomials to do this. Hence HB transmission in St Petersburg occurs mainly in young adults. The dramatic increase of infections in 1999 was probably due to injecting drug use. Without intervention, HB virus is expected to continue to spread rapidly with a greater proportion of female infections caused by sexual transmission. These trends may also provide an indication for HIV transmission. (author's)