Small Area Spread of a New Type of infectious Condition across Berkshire in England between June 2011 and March 2013: Effect on Medical Emergency Admissions.

Aims: This study aims to investigate the small area spread of a presumed infectious agent, and to determine which factors determined the point of initiation, speed of the spread and the resulting increase in emergency medical admissions. Study Design: Analysis of a monthly time series of medical admissions using small area population aggregates of around 7,000 population contained within the census spatial unit called a Mid Super Output Area (MSOA). Place and Duration of Study: Emergency medical group admissions for residents of the six unitary authority locations in Berkshire, southern England between January 2008 and March 2013. Methodology: A running twelve month total of admissions was used to determine the point of initiation and the extent of a step-like increase in medical admissions. Results: Analysis shows evidence for spatial spread initiating around June 2011 through to March 2013. At onset, medical admissions increase and stay high for 12 to 18 months before beginning to abate. This spread commenced earlier among mainly Asian small areas (clustered from July 2011 onward) and later (clustered around March 2012) in predominantly affluent white areas. The observed percentage increase in admissions within the unitary authority areas varied from 25% to 51% (median value), however the average increase was highest as the geographic area became smaller, and this is suggested to arise from the aggregation of smaller social networks where the point of initiation of infectious spread occurs over time. The percentage increase in admissions displayed high single-year-of-age specificity suggestive of the immune phenomena called antigenic original sin, and is therefore suggestive of a different strain of an agent with previous outbreaks. The increase in emergency admissions showed a month-of-year pattern which appeared to follow the seasonal pattern of vitamin D levels in the blood. The presence of nursing homes, deprivation and ethnicity also has an effect on the average increase in admissions. Conclusion: It is suggested that all the above point to an outbreak of a previously uncharacterized type of infectious agent. There are profound implications regarding the use of standard five year age bands for the standardization of medical admission rates.

Infectious-like Spread of an Agent Leading to Increased Medical Admissions and Deaths in Wigan (England), during 2011 and 2012.

Aims: To demonstrate infectious-like spread of an agent leading to a period of higher death and medical admissions in the Wigan local authority, part of the greater Manchester area of England, during 2011 and 2012. Study Design: Longitudinal study of deaths and hospital admissions. Place and Duration of Study: Deaths (all-cause mortality) for the resident population of Wigan from January 2006 to February 2014. Patients admitted to the Wigan Infirmary, a large acute hospital on the outskirts of Manchester, England, between 2008 and 2013. Methodology: Running twelve month totals for deaths and medical admissions were used to detect step-like increases in these factors. Additional analysis by age, length of stay and for clusters of persons living in over 40 small areas (called mid super output areas) containing approximately 5,000 population within Wigan and surrounds. Results: A step-like increase in total deaths can be seen for all-cause mortality in Wigan commencing around February of 2012. Medical admissions to the hospital also show a step-like increase at this point. Deaths and medical admissions remain high for around 15 months before beginning to abate. Infectious-like spread of medical admissions can be observed within 40 small area population groups in Wigan during the period January 2011 to April 2012. Certain medical conditions appear to be affected earlier than others, and the pattern of increased admissions show evidence of saw-tooth behavior with age, which is indicative of ‘antigenic original sin’ and which has also been demonstrated for deaths in England and Wales during 2012. Conclusion: The spread of a previously unidentified infectious agent is implicated in the synchronous increases in death (both in- and out-of-hospital) and in medical admissions (some of which result in death). This is not the first occurrence of an outbreak of this agent and urgent research is required to identify both the agent and clarify its mode of action which appears to be via immune modulation. The ubiquitous herpes virus, cytomegalovirus, which is known to have powerful immune modulating properties, may be involved.