New virus strain not “more deadly”

[Wandering Eyes]

In December Boris Johnson announced to UK citizens that a new strain of the Sars-Cov2 virus – B1.1.7 – was 70% more infectious and probably more deadly. His Government, including health bureaucrats, used this to justify more lockdowns.

Around the world nations responded similarly, in an echo of the first fearful wave of border closures, lockdowns and infection-control responses that followed China’s actions in Wuhan.

In New Zealand the Government took special measures to isolate returning citizens coming from the UK. The media keep referring to the strain as more dangerous. And health experts were more than prepared to use this incomplete information to recommend tougher policies against the strain.

By 22 Jan, the UK Government doubled-down on its prediction, claiming that it was 30% more deadly. To be fair, some media reporting at the time noted a lack of certainty in the data, but went ahead and reported the claims anyway. Most reports reaching the public – such as this in NZ – made no mention of the low probability.

The unthinking reporting was made possible because credible people repeated it. The almost iconic Dr Anthony Fauci, the US chief health officer, said the strain was 30% more deadly.

Here in NZ Nick Wilson claims the strain means we are in “the most dangerous period” and urges limits to number of people returning from the UK or close to the UK completely.  There is no mention of the lack of certainty.

This is important because it was all wrong.

A UK study in January found ‘some evidence’ for increased transmission but “we found no evidence for changes in reported symptoms, disease severity and disease duration associated with B.1.1.7. We found a likely reinfection rate of around 0.7% (95% CI 0.6-0.8), but no evidence that this was higher compared to older strains.

In fairness we should note that the study found that the increase in the R rate subsequently fell in lockdown. (That’s interesting and deserves follow-up because there’s no other causal evidence that lockdowns do this).

But the results of that study were not surprising. There were indications early on that this strain was not more deadly. The actual evidence given to Boris Johnson was that there was at 40-50% probability that it was more deadly.

Other studies in late December were already clear that although it did appear slightly more infectious, the symptoms were similar.

We should discuss the terminology. The most problematic phrase was “more deadly”. It was a technically accurate way of phrasing the idea that if the strain was more infectious, it would reach more people and thus kill more. Remember that it now appears to be only marginally more transmittable than earlier strains, not the 70% Johnson and his health officials claimed, and that’s only judging by its spread, not by studies of its mode of action.

The failure of the transmission data to back up the predicted spread could explain why the officials switched to a different way of saying the same thing: not that it was more transmittable but that that is was more deadly (because the same disease reached more people).

This implies that if you got the strain, you were more likely to die. But you aren’t – your chances are just the same as with other strains: 0.7%.

The choice of the word deadly is deliberate; technically correct across a population even if the difference is not much, and while absolutely not correct for an individual, the word creates personal fear.

The choice of many of the world’s senior health personalities to go along with using the word signals they are interested in the outcome, not accuracy. This makes them unreliable sources. That is bad for science, public policy, and democracy.

 

 

 

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