Two things stand out from the data & evidence:

1. When there is a surge in infections, cases eventually come down whether or not there is a lockdown/significant restrictions.
2. Lockdowns/many restrictions have little (not necessarily no) impact on hospitalisations & deaths.
Some find this hard to accept, as it seems so obvious:

Transmission comes from contact, restrictions reduce contact, so surely restrictions must reduce transmission & hence admissions & deaths?

But there are lots of reasons why restrictions may have less benefit than expected:
1. People change their behaviour voluntarily in response to changes in infections.

You choose to take less risk when infections surge, more risk when infections low, but just as importantly ...
... voluntary change has a bigger effect on riskier interactions

e.g. a student living with their vulnerable granny chooses to avoid gatherings & pub meet-ups when infections are high. People at lower risk continue to meet up.

That means ...
... shutting pubs to everyone mainly hits lower risk people, e.g. young people in flat share &/or who have already had Covid.

Voluntary behaviour change means it should be no surprise that the marginal effect of imposing (or lifting) restrictions is fairly low.
2. Restrictions change the mix of social interactions in ways which increase risk:

• Children get looked after by different family members when schools shut & parents out at work.

• When pubs with Covid-19 precautions in place shut, young people mix in (higher risk) homes ...
• Hospitality curfews lead to mass crowds on street & public transport.

• Lockdown limits low risk outdoor activity, forcing people to spend more time indoors where transmission risk is highest.
3. Lockdowns/restrictions are based on preventing lot of transmission from those who are asymptomatic, which Govt claims is 1 in 3 of those infected.

@profnfenton shows the proportion is actually much lower, so less scope for lockdowns to have an effect.
4. A sizeable proportion of serious cases & deaths come from care home and hospital outbreaks.

Local infection control measures are likely to be more important than lockdowns in affecting numbers in these settings.
In summary, it should be no surprise that lockdowns/legal restrictions have little independent impact on deaths & hospitalisations. Some restrictions may have some impact, others none at all, whilst others may even be counterproductive.
The other reason people find the data hard to accept is the implication: our policy of rolling lockdowns imposed unimaginable economic & social costs but may have been close to useless in alleviating pressure on the NHS.

For some that possibility is just too much to contemplate.

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More from @cricketwyvern

7 Apr
This morning, @BBCr4today had a piece on how badly Brazil had managed the pandemic, featuring a doctor bemoaning that they had never had a national lockdown "like you did in the UK". No challenge from the presenter of course …
… Brazil has seen a big increase in deaths in recent weeks, but no mention of the fact that their cumulative rate is still below hard-lockdown Peru and way lower than lockdown UK ...
… and no mention that the 7-day average of new reported cases in Brazil have been decreasing since 27 March, whilst the estimated R rate has been decreasing since mid-March ...
Read 6 tweets
25 Mar
Lots to enjoy in this thread about the end of the Texas mask mandate on 10 March. See also @ianmSC 's other thread on Mississippi which removed the mask mandate earlier on 3 March.
What stands out is how it is a matter of blind faith for so many commentators, including leading health experts, that these sort of restrictions must be effective. Evidence and data just have no impact on them.
In the UK, getting rid of the mask mandate should be first on the list for the road map, not relegated to a "review" in June. The risk of any impact on infection rates is very low, whilst the benefits would be very high ...
Read 7 tweets
24 Mar
Yes, disgraceful for the PM to signal support for such unjust discrimination. However, if it is genuinely up to the business, I suspect the free market will soon consign the suggestion to the dustbin ...
... Given the costs of checking & risk of legal challenges on grounds of discrimination, the only reason a pub would deliberately turn unvaccinated away is if there is really big demand from the public for vaccinated-only pubs ...
... people may well say they like the idea in response to an opinion poll but I would be surprised if there was much demand in practice. ...
Read 6 tweets
24 Mar
Update to various Covid-19 indicators for England.

Another big drop in deaths, hospitalisations down too.

Positive tests down & good to see no further rise in school age: data to 19 Mar, last day of in-school testing.

Zoe has been up & down: down a bit today (data to 20 Mar).
Positive tests for school ages by specimen date will be even harder to interpret over next few days due to start of at home mass LFD testing on Sun 21 March. This is meant to be followed up by a confirmatory PCR test so bear in mind ...
... an LFD positive followed by a PCR positive will only count as 1 new positive but:

1. The case will be allocated to the LFD specimen date but when the PCR test is in, that will be deleted & the case added to the PCR specimen date ...
Read 4 tweets
18 Mar
Update to various Covid-19 indicators for England:

• Another big drop in deaths.
• No further rise in Triage whilst Zoe down again.
• Positive tests down (just) overall, no change in school ages

A few other points to note …
1. Daily admissions drops back to 72 for Midlands (16 Mar), making me more suspicious that the leap to 116 on the 15th may have been a data problem.

2. 7-day ave for positive tests goes up to last Sat. Not a “school mass testing” day so not surprising no further increase ...
3. I've switched back to reporting 4-19 for school ages (rather than 10-19) as testing has also ramped up in primaries (though not as much as secondaries).

In any case, 4-19 more relevant going forward in seeing any impact of school opening itself (rather than mass testing) ...
Read 4 tweets
27 Feb
This slide from yesterday’s press conference is a bit naughty in my opinion.

It is clearly trying to imply that infections only fell after the start of 5 Jan national lockdown.

The problem is ...
... the graph does not show new infections (incidence) but the total number who would test positive at any one time (prevalence).

Incidence of new positive tests will have peaked earlier than prevalence & the peak of new infections will have been earlier still.
ONS modelled estimates actually place the prevalence peak at 1st Jan implying an infection peak probably even before Christmas.

That's a bit earlier than implied by other indicators (Zoe, actual positive tests etc.) but all show infections falling well before national lockdown.
Read 5 tweets

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