Indoor air quality and nosocomial infections: what consequences in health care institutions and how to prevent them?


Hospital-acquired infections are a real scourge for hospitals and clinics. Affecting nearly 653,000 patients each year only in the UK for instance, some of them could be avoided, especially those transmitted by air. What are the consequences of the Covid-19 on the number of nosocomial infections? What costs do they entail? What are the means of prevention? NatéoSanté explains.

What role does air quality play in the transmission of nosocomial infections?

There are two modes of transmission of nosocomial infections:

  • directly linked to the care provided in hospital (on catheters for example), especially during surgical interventions in operating theatres (endogenous infections),
  • through the air, airborne (cross-infections or exogenous). These are more frequent during epidemic episodes (mainly in winter).

Air quality plays an important role in the transmission of certain nosocomial infections. Due to the large number of people present in hospitals and clinics, the indoor environment is constantly subject to high concentrations of micro-organisms (bacteria, viruses, pathogens, germs, etc.).

Hundreds of people cross paths every day in hospitals or clinics
Every day, many people cross paths in healthcare facilities

Every day, hundreds of patients, staff (nurses, maintenance workers, etc.) and external visitors cross paths in health care institutions.

The main risk of transmission lies in microdroplets: the simple act of speaking and breathing generates droplets, the lightest of which persist in the air, in suspension. They are therefore likely to be breathed in by other people.

What impact has the Covid-19 crisis had on hospital-acquired infections?

If the most frequent micro-organisms in the cause of nosocomial infections were Escherichia coli, staphylococcus aureus, aspergillus fumigatus, or streptococcus, since 2020, Covid-19 has become the first nosocomial infection in healthcare institutions in France.

Last July, the magazine Hospimedia reported that “more than 60,000 people have contracted Covid-19 in French health establishments, while other nosocomial infections have been more discreet since the beginning of the pandemic”.

How can this be explained? As detailed by Santé Publique France in its report of 19 November 2020, infections are very often due to the loosening of barrier measures, in particular the removal of masks, whether between hospital patients and doctors, from patient to patient (particularly the problem of double rooms), by relatives, or even during breaks for care staff. According to SPF, this last case is the cause of 20% of infections.

During staff breaks, barrier gestures are no longer applied
Barrier gestures are often relaxed during breaks

Furthermore, it has been proven in various studies that the transmission of SARS-CoV-2 is mainly airborne, as the World Health Organisation pointed out in a July 2020 note: “Respiratory droplets are larger than 5-10 microns in diameter. As they evaporate, some of them generate microscopic aerosols, with a diameter of less than 5 microns, which remain suspended indoors.”

What are the economic consequences of nosocomial infections?

Nosocomial infections have financial consequences, in particular due to the longer stay of the patient in hospital, but also to the medical examinations and care related to the monitoring and treatment of the disease.

Today, there is very little recent data on the additional costs of hospital-acquired infections in France. A report by the OPEPS (Office Parlementaire d’Evaluation des Politiques de Santé) proposes an analysis based on several studies carried out in different countries (study carried out before the pandemic).

The conclusions are as follows: “Applying a range of average additional costs of 3,500 to 8,000 euros per infection to the 750,000 nosocomial infections per year, we arrive at a total expenditure of 2.4 to 6 billion euros. Thus, a 10% reduction in the number of infections would lead to savings of 240 to 600 million euros”.

How to prevent airborne infections in health care facilities?

What monitoring obligation in hospitals and clinics?

Since 1999, a network called RAISIN (Réseau d’Alerte, d’Investigation et de Surveillance des Infections Nosocomiales) has been responsible for monitoring nosocomial infections in French health establishments, both public and private.

At hospital level, it is the CLINs (Comités de Lutte contre les Infections Nosocomiales – Committees for the Fight against Nosocomial Infections) that determine the actions to be taken to prevent nosocomial infections, which must then be implemented by the EOHHs (Equipes Opérationnelles en Hygiène Hospitalière – Operational Hospital Hygiene Teams).

Purifying the air to reduce the risk of airborne transmission of hospital-acquired infections

Hygiene is the key word for the prevention of nosocomial infections in health care institutions (hospitals, clinics), staff and patients themselves.

Patients and their relatives are potential sources of bacteria and viruses. Therefore, they have to follow certain strict rules such as wearing a mask, disinfecting their hands and physical distancing.

Professional air purifier secures indoor air in confined spaces in healthcare facilities
A professional air purifier is particularly suitable in hospitals to rid the air of micro-organisms

In addition, within the hospital itself, teams must pay particular attention to the permanent cleanliness of the premises, including surfaces, without forgetting indoor air hygiene, which is also essential in the fight against nosocomial infections.

As these are widely transmitted through the air, it is strongly recommended that patient rooms and common areas (reception, waiting room, cafeteria, staff break room, etc.) be equipped with professional air purifiers with proven efficacy in removing viruses, bacteria and micro-organisms from the indoor air and thus avoiding the risk of cross-contamination within the establishment as much as possible.

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