Omicron update: London followed Gauteng after all

Analysis

07:27

Britain’s most prestigious scientists managed to deny the obvious

by Pieter Streicher

A resident walks past Kliptown train station in Soweto, Guateng. Credit: Getty

A host of reasons why the South African experience of Omicron would not necessarily be replicated in the UK were offered by high-status science commentators throughout December. The British population is older, less immune, the South African data is unreliable, etc. The claim was that even though the wave had been much milder than Delta in a South African context, it could still be much worse in Europe and still overwhelm British hospitals.

Professor Neil Ferguson’s Imperial College team even conducted a study in late December that managed to conclude that there was ‘no evidence’ that Omicron was milder than Delta – based on the same theory that differences in outcomes could only due to immunity rather than inherent to the virus. Patrick Vallance and Chris Whitty, Britain’s medical and scientific leaders, were persuaded and lobbied the government for further restrictions before Christmas based on the same apparent uncertainty.

And yet it turns out once again that the obvious was true after all.

Now that cases have peaked in London (since 23rd December actually) and hospital variables are in decline, it is possible to compare peak levels between London and the province of Gauteng in South Africa, where the Omicron wave began. There are very real differences between the two cities: Gauteng has relatively high previous infection levels and low vaccination rates, while London has lower previous infection rates and high vaccination rates. Gauteng has a younger population compared to London. Despite all this, the Case Fatality Rate (CFR) fell 5-7 times in both areas between Delta and Omicron.

The maximum number of hospital admissions per day was slightly higher in London at 4.6 / 100k compared to 3 / 100k in Gauteng. Highest hospital beds were slightly higher in London with 34 beds / 100,000 compared to 23 beds / 100,000 in Gauteng. Due to poor public hospitals in Gauteng, many people in disadvantaged communities only go to the hospital as a last resort, which partly explains the lower hospital population in Gauteng.

The level of infection was assessed to be the same in both urban areas. London performs dramatically more tests than Gauteng, which explains the significantly higher cases.

The peak in ventilated beds was lower in London with 0.5 beds / 100k compared to 0.8 beds / 100k in Gauteng. Peak Omicron deaths were also lower in London at 0.17 / 100k per year. day compared to 0.22 / 100k per. day in Gauteng.

But across all of these goals, it’s remarkable how small these differences are for two such different places on opposite sides of the world.

Just before December 18, 2021, when England was considering increasing the restrictions from Plan B, SAGE warned that if Britain were to continue with Plan B alone, it could see 600-6,000 deaths a day. This works at 0.9-9.0 deaths / 100k. London appears to have peaked at a level of 0.17 deaths / 100k, which is 5 times lower than the lower limit and 50 times lower than the upper limit.

The question is still how did SAGE manage to get it so wrong? There appear to be three main causes: 1) Use of a similar inherent virulence in Omicron compared to Delta, despite evidence to the contrary 2) Assumption of a significant reduction in the efficacy of the vaccine against serious disease with Omicron, which does not occurred 3) Overestimating the rate of attack during the Omicron wave itself.

In fact, the early data from South Africa proved to be a better guide than the most sophisticated models produced for the British government.

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