Expert review of vaccines
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Expert review of vaccines · Mar 2010
ReviewVaccination: a new option to reduce the burden of herpes zoster.
There is a strong correlation between the incidence of herpes zoster (HZ) and increasing age, with a marked rise in incidence from approximately the age of 50-60 years. The lifetime risk is approximately 25% and the disease is associated with acute and sometimes persistent pain, which substantially reduces the day-to-day functioning and quality of life of affected individuals, particularly older adults. The disease most commonly occurs as a result of an age-related decline in cell-mediated immunity. ⋯ A continuation trial from the Shingles Prevention Study involving over 14,000 patients approximately 7000 in the HZ vaccine and placebo groups) confirmed that the efficacy of vaccination against HZ is durable through 7 years in terms of a significantly reduced incidence of HZ, a reduced incidence of postherpetic neuralgia and a markedly lower burden of illness. Although significant improvements have been made, available treatment options are only partially effective, and once postherpetic neuralgia is established, management is difficult. Therefore, the introduction of the zoster vaccine is a promising strategy to reduce morbidity associated with HZ, a particular concern in older adults.
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Enterovirus 71 (EV71) was first isolated in 1969 in California, USA. Several epidemic outbreaks with high mortality rates have occurred in European and Asian Countries (Bulgaria in 1975, Hungary in 1978, Malaysia in 1997, Taiwan in 1998 and China in 2008). ⋯ Recently, several EV71 vaccine candidates, including live-attenuated virus, inactivated whole virus, recombinant viral protein, virus-like particle and DNA vaccines, have been evaluated in animals but no clinical trial has yet been conducted. Based on historical experiences with poliovirus vaccines and animal studies, the inactivated whole-virus vaccines are feasible and could be licensed readily, so these are targeted for preparing clinical trials in several organizations in Asia.
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Worldwide, rotaviruses are the single most important agents of severe gastroenteritis in infants and young children. Globally, it is estimated that every year rotavirus gastroenteritis causes more than 125 million episodes of diarrhea and nearly 527,000 deaths, mainly in developing countries. The development of new effective and safe rotavirus vaccines was recognized as the most effective intervention strategy that could yield a significant impact on the burden of rotavirus disease. ⋯ In a recently completed vaccine trial in South Africa and Malawi, Rotarix showed an overall efficacy of 61.2% (95% CI: 44.0-73.2) by 1 year of age. Although these rates are lower than those from developed and middle-income countries, they look promising given the lack of other effective interventions. With the expanding introduction of rotavirus vaccines into national immunization programs, postmarketing surveillance should be conducted to measure the impact of rotavirus vaccination, as well as continued monitoring of circulating rotavirus strains.
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Cervarix and Gardasil are two prophylactic HPV vaccines designed primarily for cervical cancer prevention. Cervarix is effective against HPV-16, -18, -31, -33 and -45, the five most common cancer-causing types, including most causes of adenocarcinoma for which we cannot screen adequately. ⋯ The most important determinant of vaccine impact to reduce cervical cancer is its duration of efficacy. To date, Cervarix's efficacy is proven for 6.4 years and Gardasil's for 5 years.