Vaccine
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Influenza A is a viral disease of global dimension, presenting with high morbidity and mortality in annual epidemics, and in pandemics which are of infrequent occurrence but which have very high attack rates. Influenza probes reveal a continuing battle for survival between host and parasite in which the host population updates the specificity of its pool of humoral immunity by contact with and response to infection with the most recent viruses which possess altered antigenic specificity in their hemagglutinin (HA) ligand. HA ligand binds the virus to the cell to bring about infection. ⋯ Pandemics are believed, conventionally, to be derived solely by rare events in which wild viruses of man acquire a new HA ligand of avian origin. There might be an alternative possibility involving a periodicity in selective control by the host population itself, in its receptivity or rejection at a particular time of particular reassortant viruses which might be created more frequently in nature than we are presently aware. This hypothesis, though remote, provides a different way to view and to probe the enigma of pandemic influenza.
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This review discusses recent progress in the development of a vaccine against Helicobacter pylori. This progress includes demonstration that: effective immunisation is independent of antibodies but dependent upon CD4+ T helper cells, although their role remains unknown; the immunisation regime can be improved to increase efficacy; successful immunisation against H. pylori is possible using a live vector; a strain of H. pylori suitable for experimental infection of humans has been developed. Important issues that remain to be addressed include incomplete protection, non-availability of suitable mucosal adjuvants and post-immunisation gastritis. Significantly, commercial development of products for clinical trial is underway.
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We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a different influenza intervention in healthy adults: Vaccines; Ion Channel Inhibitor antivirals and Neuraminidase Inhibitor (NIs) antivirals. The objectives were to identify, retrieve and assess all studies evaluating the effects of these interventions in prophylaxis and early treatments of influenza and the frequency of adverse events. Additionally we present the results of the economic evaluation of effective alternatives in order to define the most cost-effective intervention. The economic evaluation is set in the context of the British Army. ⋯ If assessed from the point of view of effectiveness and efficiency, vaccines are undoubtedly the best preventive means for clinical influenza in healthy adults. However, when safety and quality of life considerations are included, parenteral vaccines have such low effectiveness and high incidence of trivial local adverse effects that the trade-off is unfavourable. This is so even when the incidence of influenza is high and adverse effect quality of life preferences are rated low. We reached similar conclusions for antivirals and NIs even at high influenza incidence levels. On current evidence we conclude in healthy adults aged 14-60 the most cost-effective option is not to take any action.
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Review
Success stories in the implementation of universal hepatitis B vaccination: an update on Italy.
Compulsory universal vaccination against hepatitis B was introduced in 1991 in Italy for all newborns and 12-year-olds. Despite the decreasing circulation of the virus noted in the late-1980s, it was clear that only universal immunization would control hepatitis B infection and limit the transmission of the virus. ⋯ Since 1995, the decrease in acute cases of hepatitis B has accelerated in the age groups 0-14 and 15-24, particularly in two regions of the north; during the same period, no comparable decrease in incidence was seen in older age groups. Monitoring coverage of vaccination and incidence of acute disease and seroepidemiological studies will continue and should show a rapid progression towards the elimination of HBV circulation in the country.
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The most menacing complication of herpes zoster in immunocompetent elderly people is chronic pain or postherpetic neuralgia (PHN). The cardinal epidemiological feature of PHN is its striking relationship to aging. Among zoster patients over 60 years old, estimates of the occurrence of PHN, defined as pain 1 month after rash onset, vary from 27 to 68%. ⋯ The outcomes of this pain include fatigue, sleep disturbance, anorexia, depression, social withdrawal, impaired activities of daily living and profound lowering of quality of life. The management of PHN is hampered by two problems: (1) a uniformly effective treatment for PHN is not available (although tricyclic antidepressants, local or regional anaesthetics, capsaicin, opiates, anticonvulsants and physical therapies are sometimes useful); and (2) early antiviral therapy of zoster may be ineffective in preventing PHN, partly related to the fact that days of VZV replication and neuronal destruction have occurred by the time the patient reaches the doctor. A potential solution to the problem of PHN is the vaccination of elderly persons with the varicella vaccine to prevent or attenuate zoster or PHN.