❦ from ‘The Lancet COVID-19 Commission Task Force on Safe Work, Safe School, and Safe Travel’:

‘Buildings play a critical role in minimizing, or conversely exacerbating, the spread of airborne infectious diseases.’

‘Buildings play a critical role in minimizing, or conversely exacerbating, the spread of airborne infectious diseases.

COVID-19 outbreaks occur indoors, and within-room long-range transmission beyond two meters (six feet) has been well documented in conditions with no masking and low ventilation rates.

However, the relationship between building systems and airborne infectious disease transmission predates SARS-CoV-2, the virus that causes COVID-19.

Building-related interventions have been shown to reduce the spread of many other airborne infectious diseases, including severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), tuberculosis, measles, and influenza.

Following the 2009 H1N1 influenza A pandemic, an epidemiological investigation at a boarding school in Guangzhou, China found that opening windows for outdoor air ventilation was the only control measure that had significantly protected against infection.

Other research confirmed that enhanced outdoor air ventilation can reduce influenza and tuberculosis transmission in school buildings.

Similarly, upper-room ultraviolet (UV) germicidal irradiation installed in Philadelphia-area schools substantially reduced measles spread during an epidemic.

As of early 2021, no in situ research has evaluated the independent impact of ventilation and air cleaning for reducing the risk of COVID-19 transmission in schools.

However, there are a number of studies in which enhanced ventilation was used as part of layered risk reduction strategy, resulting in the successful reduction of COVID-19 infections.

For example, COVID-19 cases and mitigation strategies were tracked in schools in two cities in Missouri in December 2020.

Schools that used a combination of mitigation strategies including improved outdoor air ventilation were found to have lower rates of transmission compared to the rest of the community.

COVID-19 transmission among children in Baden-Württemberg, Germany was also rare in schools and childcare settings that employed mitigation strategies which included improved ventilation.

Conversely, inadequate outdoor air ventilation has been explicitly implicated in several large COVID-19 outbreaks across various indoor environments.

Case studies have included a choir rehearsal with poor ventilation and no masks; a meat processing facility with low air exchange rates and high rates of unfiltered recirculated air; a spin class without masks and inadequate air circulation; a bus with an air conditioning system on recirculating mode, and a restaurant with poor ventilation and an air conditioner that recirculated air through the dining room.

These counterexamples demonstrate that building-level strategies, including ventilation and air cleaning, are key components of risk reduction strategies for airborne infectious diseases, including COVID-19.

Schools are chronically under-ventilated.’

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‘Schools are chronically under-ventilated.’

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📖 (April 2021 ~ The Lancet COVID-19 Commission) The Lancet COVID‐19 Commission Task Force on Safe Work, Safe School, and Safe Travel.

Designing infectious disease resilience into school buildings through improvements to ventilation and air cleaning.

© 2021 The Lancet COVID-19 Commission.

‘The Lancet COVID‐19 Commission Task Force on Safe Work, Safe School, and Safe Travel’.

‘Designing infectious disease resilience into school buildings through improvements to ventilation and air cleaning.’

📖 (April 2021 ~ The Lancet COVID-19 Commission ~ PDF) The Lancet COVID‐19 Commission Task Force on Safe Work, Safe School, and Safe Travel. Designing infectious disease resilience into school buildings through improvements to ventilation and air cleaning ➤

© 2021 The Lancet COVID-19 Commission.