COVID-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.  

The study included data from November 2021 to January 2022, and included 1m people with Omicron infection, and 500,000 with Delta. The key finding is that when comparing Omicron with Delta, the adjusted hazard ratios were:

  • Hospital attendance: 0.56 (95% CI 0.54–0.58)
  • Hospital admission: 0.41 (0.39–0.43)
  • Death (any cause within 28d): 0.31 (0.26–0.37)

Past infection gave some protection against death in both vaccinated and unvaccinated individuals, reinforcing the idea that “infection is the best vaccination” (but not necessarily the best strategy…!). Important to note that this study only look at short-term outcomes, and did not measure any long term impact of COVID-19 infection: something in the region of 10% of people who have had COVID-19 infection are still experiencing some symptoms 12 weeks later. However, most of these are things like changes in taste and smell. More life-limiting long COVID-19 symptoms seem to be occur in around 1-5% of cases. (Important to note that being vaccinated really reduces the risk of long COVID-19 developing – somewhere between 15 and 50%.)

What does this mean? It’s certainly true that “COVID ain’t what it used to be” in terms of clinical outcomes. Omicron has continued the trend away from virulent infection with poor outcomes. Does that mean we should give up all prevention measures and let COVID-19 run riot in our hospitals this autumn and winter? Absolutely not! But perhaps it is time to view COVID-19 through a similar prism as other respiratory viruses to guide our prevention measures? Through this prism, I’m feeling less excited about the more disruptive prevention measures (like testing everybody and everything in sight) and more focussed on a symptomatic approach to the management of SARS-CoV-2 over the winter.


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