There’s been no shortage of doomsayers when it comes the discovery of the Omicron. The truth is that we don’t know enough yet to assess what the public health impact of Omicron will be compared with Delta. Yet.
The keys to making that determination depend on:
- How transmissible Omicron is;
- What the clinical presentation is for persons with an Omicron infection (compared to Delta); and
- Whether immunity people have built from vaccinations or previous infections provide substantial protection from being infected with or having a bad outcome from Omicron.
The main way that Omicron could displace Delta is if it’s more transmissible than Delta (currently 99% of global infections are Delta). If Omicron is less transmissible (regardless of the clinical symptoms Omicron presents) then Omicron will likely die out. If Omicron is slightly less transmissible than Delta, but substantially evades immunity people have previously acquired, then Omicron might be able to compete with Delta. If Omicron is more transmissible than Delta (regardless of clinical presentation and immunity escape) it will take over (like Delta displaced Alpha).
Another key piece of information we’ve yet to discover is just how dangerous Omicron is compared with Delta. Is an Omicron infection worse than outcome that Delta (and if so- in what populations)?
Is Omicron Worse than Delta? There Are 3 Possibilities
Omicron could be less dangerous to public health than Delta if it’s more transmissible, has a milder clinical presentation, and if previously acquired immunity still provides protection from infection and bad clinical outcomes.
Omicron could be a wash if it’s less transmissible than Delta and previously acquired immunity still provides protection. In that case, Omicron will die out too. Omicron could end up being about as transmissible as Delta, have a similar clinical presentation to Delta, and be substantially covered by acquired immunity – in which case Delta and Omicron could replicate side by side without a substantial change in public health impact.
Omicron could be more dangerous if it’s more transmissible and has the same or worse clinical presentation compared to Delta and/or escapes previously acquired immunity. If Omicron has a substantially worse clinical presentation and is more transmissible than Delta- that would be really bad.
The point is that we don’t have enough information from the ongoing epidemiological investigation in the Republic of South Africa to determine whether Omicron poses the same, more, or less threat compared to Delta. The Republic of South Africa has impressive research institutions and a competent national health department- so before December is over, we should have the answers to those 3 key aspects:
- Transmissibility;
- Clinical Presentation; and
- Immunity escape.
Those pieces of information will tell us whether Omicron is a bad thing, a good thing, or a wash.
