Is Cytomegalovirus Involved in Recurring Periods of Higher than Expected Death and Medical Admissions, Occurring as Clustered Outbreaks in the Northern and Southern Hemispheres?

A series of clustered infectious-like events have been recently documented in both the northern hemisphere (Canada, UK [England, Northern Ireland, Scotland and Wales], all countries in the European Union, and the USA) and the southern hemisphere (Australia and New Zealand), in which both deaths and emergency admissions for a range of medical conditions appear to simultaneously rise in a step-like manner, stay high for a period of 12 to 18 months, and then revert back to the expected time trajectory.

These unique events are also observed in very small geographical areas within the population area of a single hospital or Primary Care Organisation (PCO), and this precludes explanations based on acute thresholds to admission or to PCO funding, procedures and practice. These events have been overlooked by traditional health surveillance methodologies, simply because it was assumed that neither deaths nor medical admissions could behave in this unique way. Indeed, in the UK it has been widely assumed that the increases in medical admissions arising from these events are solely due to deficiencies in the organization and delivery of health and social care, often labelled as ‘failure to manage demand’.

Based on the spectrum of medical conditions which are associated with the increased admissions and deaths, it has been proposed that the ubiquitous herpes virus, cytomegalovirus (CMV), may in some way be associated with these outbreaks. This involvement could be either by (re-)infection with a new strain, or by opportunistic reactivation in the presence of another agent. This review will examine if CMV is indeed capable of causing substantial increases in both deaths and medical admissions, and which conditions in particular would be affected.