Thread by @LHSummers

More vaccination is necessary for Covid control. I am not convinced of its sufficiency. There is a critical go forward role for testing and isolating the infected and for masking. We can all rejoin the world but for a time not on the same terms as before.

I am a non-alarmist who is proud of not getting spun up by anecdotes to become fearful. But I found @DLeonhardt's @nytimes complacency regarding risks to the vaccinated to be typical of widespread views and dangerously misplaced.

nytimes.com/2021/09/07/bri…

At the 1/5000 daily probability @DLeonhardt estimates the chance that a close relative (nephew most distant counted) will get Covid in next 6 months is two thirds.

.@DLeonhardt's estimate is likely underestimated by a factor of 3 to 5 because most people are not getting tested regularly. True asymptomatic cases don’t hurt but they can spread the disease, lead to long Covid, or foment virus evolution.

If @Leonhardt's implicit message were heeded there would be less masking and testing and more interaction and so Covid incidence would rise perhaps exponentially.

.@Harvard has required vaccination, masking and a fair amount of social distancing and is in “safe” Massachusetts.

.@Harvard incidence rate for discovered cases has been about 1/2000 a day even with weekly testing. Many cases have surely not yet been caught so 3x testing for students now in dorms is in effect. I suspect this is necessary.

The best data I’ve seen suggest that as a vaccinated 66 year old my Covid risks are like those of an unvaccinated 40 year old. I think I’d advise such a person to stay out of public indoor situations and away from people who had not been recently tested.

There is the further point that for many vaccine efficacy is likely to meaningfully decline before booster shots arrive, are administered and take hold. We have no basis for judgement about the rate at which efficacy declines after 9 months.

The broad point is that after the experiences this year with phenomena ranging from forest fires to inflation and from Covid to Afghanistan, we need to learn to hope for the best and plan for the worst.

From the beginning of Covid we have underestimated the importance of rapid testing followed by isolating those infected. It needs to be central going forward, even if we are successful in raising vaccination rates.

This is the responsibility of governments and of businesses as they interact with employees and customers and all of us as we interact with others.