Vaccine
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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.
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The objectives of surveillance for vaccine preventable disease vary with the stage of the vaccination programme. Pre-implementation data is required to estimate the burden of disease and to decide on the appropriate vaccination strategy. Post-implementation data is required to monitor effectiveness but when high coverage is achieved surveillance must be able to accurately identify remaining pockets of susceptible persons. ⋯ Where the incidence is low, however, this approach, will be very expensive. Surveillance of vaccine preventable disease therefore requires flexible surveillance systems which are able to adapt to changes in incidence of infection and in control policy. The use of multiple data sources and supportive information from special studies is essential for the valid interpretation of routine data.
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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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Clinical Trial
Local and systemic isotype-specific antibody responses to equine influenza virus infection versus conventional vaccination.
Inactivated alum-adjuvanted conventional equine influenza virus vaccines are of poor efficacy and offer limited short-term protection against infection. In sharp contrast, natural infection with equine influenza virus confers long-term protective immunity. In order to identify the protective immune responses to equine influenza virus, the influenza virus-specific IgA, IgGa, IgGb, IgGc and IgG(T) antibody responses in nasal secretions and serum induced by natural infection and a commercial vaccine were studied by ELISA. ⋯ Challenge infection 100 days after vaccination resulted in clinical signs of infection and viral shedding. Antibody responses to vaccination were restricted to serum IgG(T) responses only. These results demonstrate that the protective immunity generated by natural equine influenza virus infection is associated with a mucosal IgA immune response and humoral IgGa and IgGb sub-isotype responses, and that this pattern of response is not generated by conventional vaccines.
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Introduction of influenza viruses with gene segments of avian origin into the human population may result in the emergence of new pathogenic human influenza viruses. The recent infection of a 3-year-old boy with an influenza A (H5N1) virus of avian origin can be considered as an example of such an event. However, this virus, influenza A/Hong Kong/156/97 (H5N1) and the 17 additional H5N1 viruses isolated from humans by the end of 1997 lack the ability to spread efficiently amongst humans and therefore have limited pandemic potential. However, the possibility of reassortment of these viruses with currently circulating human viruses illustrates the need for pandemic preparedness.