Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Aug 2011
ReviewPandemic novel 2009 H1N1 influenza: what have we learned?
In March 2009, cases of influenza-like illness in Mexico caused by a novel H1N1 virus containing genes from swine, avian, and human influenza strains were reported. Within several weeks, 2009 H1N1 disseminated rapidly and was the predominant influenza strain globally. On June 11, 2009, the World Health Organization declared that criteria for an influenza pandemic had been met. ⋯ Because most infected individuals have mild, self-limited disease, the risk/benefit assessment for early access to antiviral agents must balance the potential benefit for reducing transmission, disease severity, and burden on health care providers against the potential for dissemination of viral resistance and drug-related adverse events. Monovalent vaccines against 2009 H1N1 were developed and ready for distribution by September 2009, but initial supplies were inadequate to impact the bulk of cases that occurred in the Northern Hemisphere between April and September 2009. Continued efforts to develop universal vaccines and improve access to effective vaccines are critical.
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Adenoviruses (AdV) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal (GI) tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or encephalitis. Adenovirus infections are more common in young children, owing to lack of humoral immunity. ⋯ Treatment of AdV infections is controversial because prospective, randomized therapeutic trials have not been done. Cidofovir is considered the drug of choice for severe AdV infections, but not all patients require treatment. Vaccines have been shown to be highly efficacious in reducing the risk of respiratory AdV infection but are currently not available.
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Viral respiratory infections cause significant morbidity and mortality in infants and young children as well as in at-risk adults and the elderly. Although many viral pathogens are capable of causing respiratory disease, vaccine development has to focus on a limited number of pathogens, such as those that commonly cause serious lower respiratory illness (LRI). Whereas influenza virus vaccines have been available for some time (see the review by Clark and Lynch in this issue), vaccines against other medically important viruses such as respiratory syncytial virus (RSV), the parainfluenza viruses (PIVs), and metapneumovirus (MPVs) are not available. This review aims to provide a brief update on investigational vaccines against RSV, the PIVs, and MPV that have been evaluated in clinical trials or are currently in clinical development.
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Semin Respir Crit Care Med · Aug 2011
ReviewRespiratory viral infections in hematopoietic stem cell and solid organ transplant recipients.
Respiratory viral infections (RVIs) are common causes of mild illness in immunocompetent children and adults with rare occurrences of significant morbidity or mortality. Complications are more common in the very young, very old, and those with underlying lung diseases. ⋯ Modern molecular technology has now made it possible to detect other RVIs including human metapneumovirus, coronavirus, and bocavirus, and the role of these viruses in causing serious disease in transplant recipients is still being worked out. This article reviews the current information regarding epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment of these infections, as well as the aspects of clinical significance of RVIs unique to HSCT or SOT.
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Influenza viruses are major human pathogens with a global distribution, accounting for more than 500,000 annual deaths worldwide and with considerable impact on the quality of life and productivity of the society. Due to the limited efficacy of vaccination, antiviral drugs constitute a complementary approach in the control and prevention of influenza infections and thus play an important role in the management of influenza outbreaks and pandemics. Currently, adamantanes and neuraminidase inhibitors (NAIs) are the only two classes of anti-influenza agents approved for clinical use. ⋯ Nevertheless, oseltamivir-resistant strains have also been reported quite frequently, as in the case of seasonal H1N1 viruses that circulated between 2007 and 2009. Indeed, the emergence of drug-resistant virus variants is always a matter of concern because it could significantly compromise the usefulness of such intervention. This highlights the need for continuous monitoring of resistance markers, as well as the development of new anti-influenza drugs and combination therapies.