Just Read: Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period – Social Distancing Through 2022

2020.03 COVID Ted Eytan MD-1001 890
Kissler SM, Tedijanto C, Goldstein E, Grad YH, Lipsitch M. Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period. Science (80- ) [Internet]. 2020 Apr 14;eabb5793. Available from: https://www.sciencemag.org/lookup/doi/10.1126/science.abb5793

2020.03 COVID Ted Eytan MD-1001 890 (View on Flickr.com)

This paper, widely shared in the media, is where the idea that social (physical) distancing may have to extend into 2022 has come from.

The analysis, produced by scientists at Harvard, is clever and attempts to model the SARS-CoV-2 virus based on what we know about the transmission of other known coronaviruses, including duration of immunity and seasonality.

“With current and expanded critical care capacity, the epidemic concluded by July 2022 and social distancing measures could be fully relaxed by early- to mid- 2021.”Kissler SM, Tedijanto C, Goldstein E, Grad YH, Lipsitch M. Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period. Science (80- ) [Internet]. 2020 Apr 14;eabb5793. Available from: https://www.sciencemag.org/lookup/doi/10.1126/science.abb5793

The image above is of the scenario that’s being quoted in the media. I’ve reproduced it (it’s @CreativeCommons licensed, thank you) to show the nuance of this scenario:

  • Physical distancing would happen in bursts / intermittently, so it would not be constant. This is important according to the authors because if distancing was constant, the population would not become immune (“herd immunity”). Therefore, there would be periods of relaxation. This is reassuring.
  • This is dependent on
    • A protective antibody response from being infected (still don’t know this is the case)
    • Testing to determine when it’s time to go back to distancing (still don’t know when this will happen)
    • Other crude measures could be used to decide when to go back to distancing, such as health care use, which would trail distancing relaxation by about 3 weeks
  • This scenario requires a doubling of capacity to handle virus infections, via any/all of the following
    • Doubling of health care capacity
    • New treatments
    • Vaccine creation

The “end” happens when there’s herd immunity, a fully effective treatment, or a vaccine. This model presents that possibility based on distancing alone.

It looks like either way, our health care system would be fairly fully deployed during this entire time. Support your health care professional colleagues 🙂 .

For an explanation from one of the authors (@yhgrad), here’s a clip from CNN.

And tweet from one of the authors (@mlipsitch), who can be followed for more information

I’m thankful for the scientists who are social so that we can have them explain their own work.

Reference

Kissler SM, Tedijanto C, Goldstein E, Grad YH, Lipsitch M. Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period. Science (80- ) [Internet]. 2020 Apr 14;eabb5793. Available from: https://www.sciencemag.org/lookup/doi/10.1126/science.abb5793

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