(2021-07-30) More Covid Mysteries

More Covid-19 Mysteries. How do we solve these mysteries?

Over the course of this pandemic, I have found one of my early assumptions especially hard to shake. It’s one that many other people seem to share — namely, that a virus always keeps spreading, eventually infecting almost the entire population, unless human beings take actions to stop it.

But much of the ebb and flow of a pandemic cannot be explained by changes in human behavior. That was true with influenza a century ago, and it is true with Covid now.

Britain has become another example. The Delta variant is even more contagious than Alpha, and it seemed as though it might infect every unvaccinated British resident after it began spreading in May. Some experts predicted that the number of daily cases would hit 200,000, more than three times the country’s previous peak. Instead, cases peaked — for now — around 47,000, before falling below 30,000 this week.

none of the explanations seem nearly big enough to explain the decline, especially when you consider that India has also experienced a boom and bust in caseloads

A more plausible explanation appears to be that Delta spreads very quickly at first and, for some unknown set of reasons, peters out long before a society has reached herd immunity

That’s not guaranteed to happen everywhere, and there probably will be more variants after Delta.

I don’t want anyone to think that Osterholm is making a nihilist argument. Human responses do make a difference: Masks and social distancing can slow the spread of the virus, and vaccination can end a pandemic

Osterholm’s plea for humility does have policy implications. It argues for prioritizing vaccination over every other strategy. It also reminds us to avoid believing that we can always know which behaviors create risks.

Many of the Covid rules that school districts are enacting seem overly confident about what matters, Osterholm told me. Ventilation seems helpful, and masking children may be. Yet reopening schools unavoidably involves risk.

Fortunately, school employees and teenagers can be vaccinated, and severe childhood Covid remains extremely rare.