So, a double blog day today! I couldn’t resist reading the latest statement from a UKHSA expert group on “The role of respirators and surgical masks in mitigating the transmission of SARS-CoV-2 in healthcare settings: an overview of evidence (2022)”, published yesterday, as soon as it hit my desk. “Equivocal” is a word that I try to avoid. It’s one of those ‘jargony’ and overly technical words that is best worded-around in my view. But for this, it’s about right. The evidence from well controlled clinical trials that respirators (FFP2/3 or N95s) offer superior protection to healthcare workers than surgical masks is equivocal (“open to more than one interpretation”). But does that matter? If we look to the physics of SARS-CoV-2 transmission, there is a risk that the type of small, virus-laden particles emitted by patients infected with SARS-CoV-2 could circumvent the level of protection provided by surgical masks. And so, it now seems reasonable to recommend FFP2/3 or N95s for healthcare workers caring for patients with SARS-CoV-2 (and influenza for that matter). However, given the uncertainty of the evidence base, as highlighted by this review, I can understand why some have decided to continue with a policy of surgical masks when caring for patients with SARS-CoV-2 infection in most settings.
Continue readingCOVID-19
Comparing SARS-CoV-2 air and surface contamination in the first vs. second waves
Way back during the first wave of COVID-19 (April 2020), we got our swabs out and sampled surfaces and air across a range of settings in the hospital. This cross-sectional study identified SARS-CoV-2 RNA on a rather startling 52% of surfaces and 45% of air samples collected from across the hospital and some public areas. During the second wave (January 2021), we undertook a similar exercise, and identified a vastly different level of contamination with SARS-CoV-2 RNA: 5% of surfaces and 4% of air samples. What had changed between April 2020 and January 2021 to explain this difference? A whole host of things, and we don’t know for sure – but I suspect that improved testing availability and the introduction of masks for staff and patients were the most important factors.
Continue readingOmicron and the diminishing spectre of long COVID
As we move on the journey to ‘Living with COVID’ and in doing so tolerate a greater risk of transmission of SARS-CoV-2 in society and in our hospitals, one of the issues is the threat of “long COVID”. A recent study suggests that long COVID is less common with Omicron than with previous variants, and that vaccination is effective in preventing long COVID.
Continue readingFinally, an RCT comparing N95s and medical masks to protect healthcare staff from COVID-19
Annals of Internal Medicine today published an RCT comparing the effectiveness of N95s vs. medical masks to protect healthcare staff from COVID-19. It’s a great piece of work, conducted over many years, and whilst the study has some important limitations, suggests that N95s don’t offer significantly increased protection than medical masks for healthcare staff caring for patients with confirmed or suspected COVID-19.
Continue readingOmicron COVID-19 harm and winter IPC strategy
We have just published an evaluation of Omicron COVID-19 harm as a research letter in the Journal of Infection. This multicentre study reported the findings of a retrospective review of 129 patients with healthcare-associated Omicron COVID-19, and found that the harm profile was very different to previous waves: a small proportion of patients required supplemental oxygen, escalation to critical care, had an extended length of stay, or died from COVID-19. This informs our winter IPC strategy: whilst COVID-19 is more than “just a cold”, the balance between direct and indirect harms from COVID-19 has shifted towards preventing indirect harms (like reduced hospital throughput and delayed diagnosis) and more of a focus on other issues (e.g. flu, Gram-negative BSIs etc).
Continue readingCOVID-19 ain’t what it used to be
As the COVID-19 pandemic has swept through various epidemic waves each characterised by a different variant, the trend has been towards more transmissibility but less virulence of SARS-CoV-2. The emergence of the Omicron variant continued this trend, and we are now seeing some data to compare the clinical outcomes of COVID-19 with other variants. A huge Lancet study (1.5m patients!) demonstrates clearly that the risk of hospital attendance, hospitalisation, and death is significantly lower with Omicron compared with Delta. This is important because the consequences of SARS-CoV-2 acquisition are an important factor in deciding on our management strategy – as a hospital group and in general.
Continue readingEverybody’s talking about the Lancet Commission on COVID-19
The Lancet has published a hard-hitting piece on lessons learned from the COVID-19 pandemic. The report includes a blow-by-blow account of the pandemic and the lessons that have emerged, and some important recommendations from a global public health viewpoint. Unsurprisingly, this piece has generated a lot of interest and people are talking about it, which is no bad thing!
Continue readingBeware reusable PPE!
A new JHI study highlights the dangers associated with reusable PPE, and related to PPE doffing in general. The study used a clinical simulation suite to monitor the spread of fluorescent material added to the outside of an N95 respirator during routine care for mannequin adult patients (with COVID-19!). Whilst some modes of PPE reuse were better than others, all of the clinicians involved in the study ended up contaminating the clinical environment with fluorescent material originating from the mask.
Continue readingCOVID-19 – what have we learned?
I did a talk at an IPC conference the other day trying to summarise what we’ve learned from the COVID-19 pandemic. You can see my slides here. I think (hope) we have learned a lot – and still have more to learn – about (in no particular order): PPE, transmission routes, testing and laboratory factors, vaccination, organizational transformation, guidelines and policy development, regulatory framework, outbreaks, non-COVID pathogens, antimicrobial stewardship, digital transformation, applied research, and the mental health of our workforce.
Lateral flow or PCR?
As England moves away from confirmatory PCR testing following a positive lateral flow test in the absence of COVID-19 symptoms, it’s a good time to look at what these two different testing strategies can offer us. There’s an excellent short review in NEJM combined with a case study to help illustrate the impact of pre-test probability plays out. Both lateral flow testing and PCR testing have their place, and in some ways lateral flow testing is a better correlate for infectivity (as well as being cheaper and easier!).
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Reflections on Infection Prevention and Control 