Objective To evaluate ascertainment of the onset of community transmission of influenza A/H1N1 2009 (swine flu) in England during the earliest phase of the epidemic through comparing data from two surveillance systems.Design Cross sectional opportunistic survey.Study samples Results from self samples by consenting patients who had called the NHS Direct telephone health line with cold or flu symptoms, or both, and results from Health Protection Agency (HPA) regional microbiology laboratories on patients tested according to the clinical algorithm for the management of suspected cases of swine flu.Setting Six regions of England between 24 May and 30 June 2009. Main outcome measure Proportion of specimens with laboratory evidence of influenza A/H1N1 2009.Results Influenza A/H1N1 2009 infections were detected in 91 (7%) of the 1385 self sampled specimens tested. In addition, eight instances of influenza A/H3 infection and two cases of influenza B infection were detected. The weekly rate of change in the proportions of infected individuals according to self obtained samples closely matched the rate of increase in the proportions of infected people reported by HPA regional laboratories. Comparing the data from both systems showed that local community transmission was occurring in London and the West Midlands once HPA regional laboratories began detecting 100 or more influenza A/H1N1 2009 infections, or a proportion positive of over 20% of those tested, each week.Conclusions Trends in the proportion of patients with influenza A/H1N1 2009 across regions detected through clinical management were mirrored by the proportion of NHS Direct callers with laboratory confirmed infection. The initial concern that information from HPA regional laboratory reports would be too limited because it was based on testing patients with either travel associated risk or who were contacts of other influenza cases was unfounded. Reports from HPA regional laboratories could be used to recognise the extent to which local community transmission was occurring.
Influenza related mortality rates have been established in many countries; nevertheless, studies focusing on the Central European population have been rare to date. We assess mortality attributable to influenza by comparing all cause mortality and mortality due to diseases of the circulatory system during influenza epidemic and non-epidemic periods, as defined by acute respiratory infection surveillance data. Data on total mortality, mortality due to diseases of the circulatory system and surveillance data for influenza and other respiratory infections were used in a general linear model with a logarithmic link for dependence of left censored mortality data over time, and week as a categorical factor. Results of the analysis show statistically significant (p <0.001) differences in excess mortality rates between influenza epidemic and non-epidemic periods in the Czech Republic between 1982 and 2000. We estimate that 2.17% of all cause mortality, and 2.57% of mortality due to diseases of the circulatory system throughout the study period was attributable to influenza, with an estimated annual average of 2661 and 1752 deaths respectively. The highest numbers of deaths were reported during seasons when influenza A/H3N2 was the predominant circulating strain. Improving vaccination coverage against influenza is considered to be the primary strategy for prevention of influenza associated mortality.
Influenza activity in Europe during the 2001-02 influenza season was mild to moderate. Compared to historical data, the intensity was low in six countries, medium in eleven and high in one country (Spain). The dominant virus circulating in Europe was influenza A(H3N2). Two novel influenza virus strains were isolated during the 2001-02 season: influenza A(H1N2) viruses (mainly isolated in the United Kingdom and Ireland, but also in Belgium, France, Germany, the Netherlands, Portugal, Sweden, Switzerland and Romania), and influenza B viruses belonging to the B/Victoria/2/87 lineage (mainly isolated in Germany, but also sporadically in France, Italy, the Netherlands and Norway). With the exception of H1N2 virus detections in England, and Ireland and the influenza B viruses belonging to the B/Victoria/2/87 lineage in Germany, these two viruses did not circulate widely in Europe and did not play an important role in influenza activity during the 2001-02 season. An influenza B virus belonging to the B/Victoria/2/87 lineage will be included in the 2002-03 influenza vaccine. The new subtype influenza A(H1N2) is covered by the 2002-03 vaccine, as the haemagglutinin and neuraminidase components of the H1N2 viruses are antigenically similar to the vaccine components (H1N1 and H3N2).
Although communicable diseases have hitherto played a small part in illness associated with Olympic Games, an outbreak of infection in a national team, Games venue or visiting spectators has the potential to disrupt a global sporting event and distract from the international celebration of athletic excellence. Preparation for hosting the Olympic Games includes implementation of early warning systems for detecting emerging infection problems. Ensuring capability for rapid microbiological diagnoses to inform situational risk assessments underpins the ability to dispel rumours. These are a prelude to control measures to minimize impact of any outbreak of infectious disease at a time of intense public scrutiny. Complex multidisciplinary teamwork combined with laboratory technical innovation and efficient information flows underlie the Health Protection Agency's preparation for the London 2012 Olympic and Paralympic Games. These will deliver durable legacies for clinical and public health microbiology, outbreak investigation and control in the coming years.
Coverage among high-risk patients in younger age groups continues to fall well below satisfactory levels, especially among the youngest groups. Government policy should now focus on ways to improve uptake in these patients.
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