[Description of the first three notified outbreaks of influenza A (H1N1) 2009 in Spanish prisons]

Influenza outbreak in a Canadian correctional facility

Correctional facilities face increased risk of communicable disease transmission and outbreaks. We describe the progression of an influenza outbreak in a Canadian remand facility and suggest strategies for preventing, identifying and responding to outbreaks in this setting. In total, six inmates had laboratory-confirmed influenza resulting in 144 exposed contacts. Control measures included enhanced isolation precautions, restricting admissions to affected living units, targeted vaccination and antiviral prophylaxis. This report highlights the importance of setting specific outbreak guidelines in addressing population and environmental challenges, as well as implementation of effective infection prevention and control (IPAC) and public health measures when managing influenza and other communicable disease outbreaks.

Vaccinations in prisons: A shot in the arm for community health

From the first day of imprisonment, prisoners are exposed to and expose other prisoners to various communicable diseases, many of which are vaccine-preventable. The risk of acquiring these diseases during the prison sentence exceeds that of the general population. This excess risk may be explained by various causes; some due to the structural and logistical problems of prisons and others to habitual or acquired behaviors during imprisonment. Prison is, for many inmates, an opportunity to access health care, and is therefore an ideal opportunity to update adult vaccination schedules. The traditional idea that prisons are intended to ensure public safety should be complemented by the contribution they can make in improving community health, providing a more comprehensive vision of safety that includes public health.

Spatial dynamics of airborne infectious diseases

Disease outbreaks, such as those of Severe Acute Respiratory Syndrome in 2003 and the 2009 pandemic A(H1N1) influenza, have highlighted the potential for airborne transmission in indoor environments. Respirable pathogen-carrying droplets provide a vector for the spatial spread of infection with droplet transport determined by diffusive and convective processes. An epidemiological model describing the spatial dynamics of disease transmission is presented. The effects of an ambient airflow, as an infection control, are incorporated leading to a delay equation, with droplet density dependent on the infectious density at a previous time. It is found that small droplets (∼0.4μm) generate a negligible infectious force due to the small viral load and the associated duration they require to transmit infection. In contrast, larger droplets (∼4μm) can lead to an infectious wave propagating through a fully susceptible population or a secondary infection outbreak for a localized susceptible population. Droplet diffusion is found to be an inefficient mode of droplet transport leading to minimal spatial spread of infection. A threshold air velocity is derived, above which disease transmission is impaired even when the basic reproduction number R(0) exceeds unity.