Natasha S. Crowcroft

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OBJECTIVE To assess the effectiveness of the pandemic influenza A/H1N1 vaccine used in Canada during autumn 2009. DESIGN Test negative incident case-control study based on sentinel physician surveillance system. SETTING Community based clinics contributing to sentinel networks in British Columbia, Alberta, Ontario, and Quebec, Canada. PARTICIPANTS 552(More)
Encephalitis means inflammation of the brain matter. Despite being a rare condition, encephalitis is of public health importance worldwide because it has high morbidity and mortality. Yet, many details about its epidemiology have yet to be elucidated. This review attempts to summarise what is known about the epidemiology of the infective causes of(More)
BACKGROUND In late spring 2009, concern was raised in Canada that prior vaccination with the 2008-09 trivalent inactivated influenza vaccine (TIV) was associated with increased risk of pandemic influenza A (H1N1) (pH1N1) illness. Several epidemiologic investigations were conducted through the summer to assess this putative association. METHODS AND(More)
Encephalitis causes high rates of illness and death, yet its epidemiology remains poorly understood. To improve incidence estimates in England and inform priority setting and treatment and prevention strategies, we used hospitalization data to estimate incidence of infectious and noninfectious encephalitis during 2005-2009. Hospitalization data were linked(More)
We analyzed hospitalizations in England from April 1, 1989, to March 31, 1998, and identified approximately 700 cases, 46 fatal, from viral encephalitis that occurred during each year; most (60%) were of unknown etiology. Of cases with a diagnosis, the largest proportion was herpes simplex encephalitis. Using normal and Poisson regression, we identified six(More)
BACKGROUND Evidence-based priority setting is increasingly important for rationally distributing scarce health resources and for guiding future health research. We sought to quantify the contribution of a wide range of infectious diseases to the overall infectious disease burden in a high-income setting. METHODOLOGY/PRINCIPAL FINDINGS We used(More)
An outbreak of W135 meningococcal disease was seen in 2000 and 2001 among pilgrims returning from Saudi Arabia and their contacts. The Public Health Laboratory Service set up enhanced surveillance to monitor spread and virulence of the outbreak strain, and to collect data on case characteristics. The number of cases reported from England and Wales in 2001(More)
BACKGROUND We designed a seroprevalence study using multiple testing assays and population sources to estimate the community seroprevalence of pH1N1/09 and risk factors for infection before the outbreak was recognized and throughout the pandemic to the end of 2009/10 influenza season. METHODS Residual serum specimens from five time points (between 01/2009(More)