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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Last year, the World Health Organization (WHO) convened a gathering of experts, including scientists, national regulatory authorities, industry representatives, epidemiologists and government officials from both developed and developing countries to discuss appropriate endpoint measurements for HPV vaccine efficacy and effectiveness trials. The consultation also considered the regulatory requirements and public health issues that vaccine candidates should address before deployment, particularly in developing countries. This report summarizes the discussions and the conclusions reached over the course of the consultation. The general consensus of the consultation was that it would be desirable to have a globally-agreed, measurable efficacy endpoint for considering deployment of HPV vaccines in public health settings. After hearing from experts about virological and clinical endpoints to be considered, requirements of regulatory authorities of various countries and endpoints used to measure efficacy and effectiveness for another known cancer vaccine (hepatitis B), the experts agreed that ethical and time considerations make it necessary to use a surrogate endpoint, and not invasive cervical cancer, to define efficacy of HPV vaccines. While regulatory authorities of each country ultimately will determine the endpoints required for licensure, the consultation recommended that the endpoint for efficacy in population-based studies be, based on current knowledge, histologically-classified cervical intraepithelial neoplasias (CIN) of moderate or high-grade, as well as cancer. Since persistent infection with the same high-risk type is considered a predictor for moderate or high-grade cervical dysplasias and cancer, they might represent a useful endpoint in future vaccine efficacy studies. Indeed, if vaccines prove to be effective against transient or persistent HPV infections, it is likely that they will protect women against cervical cancer. The consultation recognized that in the context of many developing countries, efficacy alone might not provide enough information for countries to decide whether or not to adopt HPV vaccines as a public health prevention tool against cervical cancer. The consultation unanimously agreed that additional clinical bridging studies as well as studies to clarify local epidemiology should be conducted in certain developing countries to determine the potential impact of vaccination. Such countries should also undertake targeted interventions to ensure acceptability and programmatic feasibility of the vaccination. Recognizing that upon vaccine introduction it will be some years before a reduction in cervical cancer is detectable at the population level, the consultation stressed the importance of maintaining existing cervical screening programmes while such long-term studies are conducted. The following paper explains the background and rationale behind these conclusions and elaborates on specific considerations for vaccine study and introduction in developing countries.
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PMID:Efficacy and other milestones for human papillomavirus vaccine introduction. 1563 Jul 92

Achieving long-term protection following vaccination is crucial to ensuring that high levels of immunity are maintained within a population while eliminating the need to introduce booster vaccinations. Based on an analysis of the hepatitis B virus vaccine, several factors have been shown to contribute to long-term protection, namely: specific lymphoproliferation, the in vivo humoral response, and immune memory. To ensure protection against persistent human papillomavirus (HPV) infection and the subsequent development of cervical lesions, an effective HPV vaccine must be able to induce strong humoral immune responses. Mathematical modeling analyses based on a three-dose regimen of HPV type 16 prophylactic vaccine indicated that 99% of 16- to 23-year-old women would have almost life-long detectable anti-HPV-16 levels. Available data on the quadrivalent HPV vaccine demonstrated that long-term immune memory was induced, with anti-HPV geometric mean titers after 5 years remaining at or above those observed with natural infection. Vaccination also resulted in a substantial reduction in the combined incidence of HPV-6/11/16/18 related persistent infection or disease, and there were no cases of precancerous cervical dysplasia compared with six cases in women receiving placebo. Similarly the bivalent HPV vaccine has been shown to induce long-term immunity with >98% seropositivity maintained after 4.5 years of follow-up and geometric mean titres at this time point remaining substantially higher than those noted with naturally acquired infection. Countrywide registration regarding population and health events in a stable population of approximately 25 million makes the Nordic countries an ideal setting for the evaluation of long-term cervical cancer control. Population-based long-term efficacy trials conducted in these countries aim to investigate the long-term efficacy of HPV vaccination with regard to invasive cervical cancer, and the results of these trials are awaited with interest.
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PMID:Long-term efficacy of human papillomavirus vaccination. 1793 16

The introduction of antiretroviral therapy (ART) in 1995 had a dramatic impact on the morbidity and mortality of the HIV population, and subsequently, the natural history of cancer has changed. The purpose of our study was to review the prevalence of AIDS-defining malignancies and non-AIDS defining cancers (NADC), taking into consideration racial and gender variations. After the institutional review board approval, the study was conducted as a retrospective chart review of 279 HIV-infected patients who were treated at the Moffitt Cancer Center between January 1, 2000 and December 31, 2010. The demographic characteristics included gender, ethnicity, race, presence or absence of ART, and the type of malignancy reviewed. Of 233 men, 78 (33.5%) had AIDS-defining malignancies. AIDS-related non-Hodgkin lymphoma (NHL) was detected in 49 (21%) patients and Kaposi sarcoma (KS) in 29 (12%) patients. Two-thirds of male patients had NADC, with anal cancer being the most prevalent (8.5%), followed by Hodgkin lymphoma (6%). AIDS-related NHL was also the predominant malignancy for women with a prevalence of 19.5% followed by invasive cervical cancer (ICC) and breast cancer, both with a similar prevalence of 11%. Kaposi sarcoma and anal cancer were equally detected in 2% of women. The prevalence rates of AIDS-defining malignancies among those of white race were 34%, ranging from 21% for NHL to 13% for KS and 1.5% for ICC. Twenty-one (7.7%) patients had anal cancer. AIDS-defining malignancies were found in 36% of patients of black race and 60% had NHL. Non-AIDS-related NHL was the second most common malignancy, followed by breast cancer and anal cancer with a similar prevalence of 6.5%. Of 279 patients, 53% were taking ART; 39.4% were not taking ART; and in 7.5% of the patients, it was unknown if they were taking ART. In the ART era, our study found NADC to be more prevalent than AIDS-defining malignancies with 60% versus 40%, respectively. Non-Hodgkin lymphoma remained the most common AIDS-related malignancy in both genders. Among the patients with NADC, anal cancer was the predominant malignancy. The increasing incidence of some of the NADC is expected as this population is living longer with chronic exposure of viral replication of virus with oncogenic potential such as Human papillomavirus (HPV), Hepatitis B virus (HBV), Epstein-Barr virus (EBV), and Human herpesvirus 8 (HHV-8). Early ART initiation, aggressive vaccination, and judicious cancer screening are the cornerstone of cancer prevention of this growing population.
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PMID:Malignancy Trends in HIV-Infected Patients Over the Past 10 Years in a Single-Center Retrospective Observational Study in the United States. 3018 62