Behind Closed Wards is an independent investigative initiative examining hospital-acquired COVID and patient safety failures in Wales.

* Infographic - American Society for Microbiology. Part of ASM’s public science communication on indoor airborne transmission of respiratory viruses, explaining how aerosols accumulate & spread in enclosed, poorly ventilated spaces. The graphic is mechanistic, not COVID-specific

This is why airborne infection control has long been part of hospital design, IPC guidance, and pandemic preparedness planning. Understanding this is key to prevention, investigation, and accountability.

Surface cleaning and hand hygiene are important, but they do not address airborne risk. Preventing aerosol transmission requires environmental and engineering controls, not just behavioural ones.

Ventilation matters. Fresh air dilution, air changes per hour, filtration, and airflow direction all affect whether infectious aerosols are removed — or allowed to build up.

In hospitals, risk increases when: • ventilation is inadequate • air changes are low • spaces are crowded • patients and staff share air for prolonged periods This is especially true on wards.

Aerosols are tiny particles released when people breathe, speak, cough, or shout. Unlike droplets, aerosols can remain suspended in the air, travel beyond close contact, and accumulate indoors.

How do aerosol viruses like SARS-CoV-2 spread in hospital settings? 🧵 Understanding airborne transmission is essential to preventing hospital-acquired COVID.

“Emergencies don’t respect borders”- stand out quote of today’s @SeneddPAC session Yet during the pandemic @MarkDrakeford pursued a distinct Welsh approach that treated the coronavirus as if it behaved differently across borders. At least one lesson learned then 🏴󠁧󠁢󠁥󠁮󠁧󠁿🦠🏴󠁧󠁢󠁷󠁬󠁳󠁿

Full analysis to follow but alarming that @WelshGovernment repeatedly emphasised that risks change & need constant attention. Failing to understand that risk modelling exists precisely to explore permutations & compounding scenarios, not simply monitoring risk as it evolves.

The First Minister for Wales @Eluned_Morgan defending the lack of independent evaluation on her @WelshGovernment implementation of the Module 1 recommendations. Starts 9.35am

Independent analysis on pandemic preparedness in Wales, including implications for airborne virus mitigation in healthcare settings. Worth reading alongside today’s evidence session.

Understanding what nosocomial COVID is — and how it spreads — is the foundation for prevention, investigation, and accountability. Future threads will explore these principles in more detail.

When patients acquire COVID-19 in hospital, this is a patient safety issue. Like other hospital-acquired harms, it requires: • investigation • understanding how exposure occurred • learning lessons • accountability where failures are identified

Preventing nosocomial infection is not primarily about individual behaviour. It is about systems, including: • ventilation and air quality • ward design and airflow • cohorting and zoning • surveillance and outbreak detection • governance and oversight

COVID-19 is an airborne (aerosol) virus. Infectious particles can remain suspended in the air, accumulate in poorly ventilated spaces, and be inhaled by others — particularly indoors.

Hospitals are high-risk environments for respiratory viruses. Patients are clinically vulnerable. Staff move between wards. Care involves close, prolonged contact. Without effective controls, airborne viruses can spread rapidly.

What is nosocomial COVID? 🧵 “Nosocomial” derives from Greek roots meaning disease (nosos) and to care for (komein), via the Latin nosocomium(hospital). Nosocomial COVID refers to patients who caught COVID-19 in hospital, not in the community.