Omicron BA.2; 2022 COVID Forecast; Napkin Calculation #8

Friday: (CNN) BA.2, the newly detected version of Omicron, is not a cause for alarm, scientists say. Quoting,

There’s no indication that BA.2 causes more severe disease or spreads more easily than the original strain of Omicron. A report released Thursday by the UK’s Health Security Agency offers additional reassurance, suggesting that current vaccines protect about as well…

Monday: (medRXiv)Transmission of SARS-CoV-2 Omicron VOC subvariants BA.1 and BA.2: Evidence from Danish Households. Quoting,

We conclude that Omicron BA.2 is inherently substantially more transmissible than BA.1, and that it also possesses immune-evasive properties that further reduce the protective effect of vaccination against infection, but do not increase its transmissibility from vaccinated individuals with breakthrough infections.

What a difference three days make! BA.2  is now dominant in Denmark.  Now look at (JHU) Timeline Comparisons; Data Sources: Cases and deaths data. Scroll down to the interactive timeline charts, Jan. 1, 2020 to present. Nota bene. Napkin calculations are not to be trusted. They can still inform.

  • Napkin Calculation #8 begins with the most primitive form of prediction, extrapolation of the smoothed chart.
  • Time between the first two  peaks: 9 months.
  • Smooth the 9/21 peak and the 1/22 peak into one, 11 months. Smoothing is necessary to avoid overfitting the data.
  • Prediction via extrapolation: A peak 9-10 months past 1/22.

Three points on a noisy graph do not make a valid extrapolation. We add factors  that could push/pull/confirm the extrapolation,  acting as substitutes for the missing graph points, a crude form of data fusion:

  • The current daily death rate is about the same as the 4/20 peak, likely the result of the countervailing effects of better interventions and less fear.
  • Assumption. Effective immunity, which wanes with time, as opposed to official vaccination status, is approaching a plateau.
  • Argument. Community presence will stabilize around levels  influenced by fear, caution, and irrational exuberance. From (CNN) CDC’s big announcement: Take Off Your Mask,

As of today, China, with 5X the population, and a poorly protective vaccine, records deaths to our 596,646. China citizens are compliant with public health regulations; U.S. citizens are not. By this metric, COVID-19 could be defined as a social problem, not medical.

  • In the U.S., BA.1 has a big head start over BA.2, delaying the next wave until  immunity induced by BA.1  wanes.

The above factors converge broadly on fall 2022. Most infectious respiratory disease is influenced by season.

  • October is favored for the next wave as a traditional seasonal factor.

Intuitively, the added factors are worth one or two more graph points.

What of severity? The speculation of Omicron, a Good Thing? is wrong. Omicron infection provides some cross immunity, at terrible cost. Whether faded immunity from Omicron, 9 months hence, reduces severity is an open question, which only a variant can answer.  Mortality will probably decline, due to increased human immune  system experience, but remain at uncomfortable levels.

Since napkin calculations are not to be trusted, what’s the takeaway? If vaccine uptake/effective immunity is plateauing,

  • Mortality statistics are likely to revert to the characteristics of earlier decades, perhaps the 1950’s.

For the foreseeable future,

  • Work-from-home is a good idea.
  • Keep immunization status current.
  • Avoid activities favored by crowds of risk-taking extroverted strangers.

 

 

 

 

 

 

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