Development of a lightweight, 'on-bed', portable isolation hood to limit the spread of aerosolized influenza and other pathogens.

Background: The annual seasonal influenza epidemics in the winter season lead to many hospital admissions, increasing risks of nosocomial infections. Infectious diseases caused by contagious respiratory pathogens also pose a great risk to hospitals as has been seen in the current epidemic by a novel coronavirus infection. Such risk occurs in high density patient settings with few or no partitions, since the pathogens are transmitted by aerosols discharged from the patients. Possible interventions against the transmission are needed.

Methods: We developed a compact, lightweight, and portable hood designed to cover just the top half of a patient sitting or lying in bed, to limit the dissemination of infectious aerosols, constructed out of lightweight pipes, transparent plastic curtains, and a fan-filter-unit (FFU). The containment efficacy of the product was tested using an aerosolized cultured influenza virus tracer and an optimal airflow rate was determined according to the test results. It was tested for use in hospital wards during the 2016-2018 influenza seasons.

Results: The hood, named as Barrihood, had dimensions height 172 cm, width 97 cm, length 38 cm, weighed 26 kg, and easily strolled and unfolded from its stored to its fully operational state of length 125 cm within a few minutes by a single operator. Optimal operational airflow-rate of the FFU was 420 L/min for containment of the aerosol particles. Eighty-one uninfected patients remained for 176 cumulative person-days within 1-4 m of influenza-infected patients isolated within the hood, without acquiring influenza infection.

Conclusions: With the use of the hood, secondary influenza infection cases significantly decreased, compared to previous influenza seasons. It may be suited to hospitals with not enough/no negative pressure facilities, or without enough number of individual patient isolation rooms, and could contribute to decrease the risk of nosocomial infections.