Many people across the world are adapting their behaviour as we all try to stop the spread of COVID-19.

We wear face masks. We stay two metres apart. We don’t mix in each other’s homes. We work from home where we can. The list varies from country to country, but we are all trying to stop the spread.

And now there is a new variant which is at least 50% more transmissible but thankfully not necessarily any more dangerous for those infected. So, we are all going to have to raise our game to keep safe until we get vaccinated. The vaccine will stop us from becoming seriously ill, but the evidence is not clear yet that the vaccine reduces our ability to spread COVID-19. In the meantime, we just all have to stay safe.

But what could happen if we are forced into a situation where we are not in control. A situation where we must rely on others to keep us safe. For example, if we must go into hospital for an operation.

You will have to self-isolate before you go into hospital and also return a negative COVID-19 test.

Hospitals have gone to great lengths to protect patients who do not have COVID-19. There are COVID-19 and COVID-19 free areas of the hospital. Staff wear full PPE all the time. Visitors are not allowed into the hospital and anyone attending a hospital must wear a face mask. The level of cleaning has also increased dramatically with attention given to surfaces and common touch-points such as door handles to prevent fomite spread of COVID-19. Staff are constantly washing their hands and using hand sanitisers.

Despite the measures that hospitals take to keep us safe, probable hospital acquired COVID-19 infections remain persistently high. Up to 20% of hospital inpatients acquired COVID-19 while in hospital in England for other reasons. ⁽¹⁾ So, where and why are people becoming infected whilst in hospital?

There are multiple possible routes of in-hospital COVID-19 transmission. Patient-to-patient transmission through contact in the same bay is a common reason. Cross infection via cases on the same ward is also not unusual. Cross-infection can also occur using shared facilities and equipment. Other sources include asymptomatic or undiagnosed staff, patients, or visitors.⁽²⁾

The reasons why patients are becoming infected when they are in hospital is summarised in a report published in October 2020 by the Healthcare Safety Investigation Branch in the UK. ⁽³⁾ In summary the investigation identified six reference trusts that represented a range of geographical locations, socioeconomic conditions, building and environmental conditions and local population ethnicity. Observations and interviews were conducted with staff at all levels within these trusts as well as national system leaders and patient focus groups. Data analysis software and an established investigation methodology were used to corroborate and triangulate the findings from multiple sources. The factors influencing the risk of nosocomial transmission of COVID-19 were identified and grouped under the headings below.

So, the take home message is that preventing hospital acquired COVID-19 is complicated. If you want to bear down on hospital acquired COVID-19 infections then, as the HSIB report points out details really do matter. It requires leadership, clear and simple communication, organisation, a good environment, well-motivated, protected people who are focused on the task and the correct equipment that supports clinical and patient related activities whilst at the same time mitigates the risk of transmission in the context of clinical and non-clinical tasks.