Friday, 5 June 2020

The inevitable face mask U-turn

Nothing was more inevitable than the British government making face masks compulsory - starting with public transport - but what a ride it has been. As with everything involving the coronavirus, we are just copying the rest of the world with a lag of a month or two

Everyone knew the government was only discouraging people from buying face masks because it wanted to make sure medics had a good supply of them. And everyone knew that face masks provided some protection against the virus because that's why medics use them.

The government's concerns were perfectly understandable, but it must have known a U-turn would eventually come, so why did the authorities leave so many hostages to fortune?

In a document from February that deserves to go down in infamy, Public Health England said that even medical staff wouldn't generally need to wear face masks:

During normal day-to-day activities facemasks do not provide protection from respiratory viruses, such as COVID-19 and do not need to be worn by staff in any of these settings.
Facemasks are only recommended to be worn by infected individuals when advised by a healthcare worker, to reduce the risk of transmitting the infection to other people. 

Perhaps, but people don't know they're infected until the symptoms appear a few days after the infection took place.

As if determined to get this paragraph included in the list of all-time bad takes, the next sentence says:

It remains very unlikely that people receiving care in a care home or the community will become infected.

That, as they say, didn't age well.

On 3 March, the day after the mayor of London claimed that there was 'no risk' of catching the coronavirus on public transport, the Advertising Standards Agency banned two adverts for face masks because they were 'misleading, irresponsible and likely to cause fear without justifiable reason'. One of the adverts said:

"It would be an understatement to say that there is a growing sense of panic.

"The best advice I've heard is to stay calm and take practical measures to protect yourself.

"One of the best ways to protect yourself is to get a high-quality face mask that can protect you from: viruses, bacteria, and other air pollutants."

Who said this was misleading? Step forward again, Public Health England...

The ASA said the adverts were "misleading" because the claims went against official advice.

A spokesman said Public Health England informed the ASA "that they do not recommend the use of face masks as a means of protection from coronavirus".

"We understood there was very little evidence of widespread benefit from their use outside of clinical settings," the ASA said in a statement.
 
NHS medical director Stephen Powis also stuck his oar in, saying:

"Callous firms looking to maximise profits by pushing products that fly in the face of official advice is outright dangerous and has rightly been banned."

A defensible position would have been to say that the evidence on the general use of face masks is mixed and that they do not guarantee protection. Instead, the authorities actively discouraged the public from wearing them and attacked the companies selling them.

In fact, the evidence that they provide some protection is quite strong (which, as I say, is why medics wear them) and Public Health England began its reverse ferret last month when it advised people to wear 'face coverings' in enclosed public places and gave us instructions on how to make them.




But remember, these are face 'coverings', not face masks, and so the science is obviously totally different and you'll have to wear them by law on public transport from 15 June. Why not straight away? God knows, but I'm sure the government is still FoLLoWiNg TeH SciEnCe đŸ„Ž.

Thursday, 4 June 2020

Smoking and COVID-19 update, plus a thought for future research

I'm finding it difficult to keep up with all the evidence on smoking and COVID-19. My last update was on 16 May so I suggest you follow Phil on Twitter if you want to get up to speed. He's catalogued 117 pieces of evidence so far in this heroic thread, most of which show smokers significantly under-represented among Covid patients/cases.

I still have my doubts about whether smoking/nicotine confers any protection against the disease. Simple comparisons between the proportion of Covid patients who smoke and the proportion of smokers in the general population are not the strongest evidence. The smoking rate in Britain, for example, is 15% and all the British studies find smoking prevalence to be about half of that among Covid patients. This one, for example, finds that only 6% were current smokers.

But the average age of patients in that study was 73 and smoking rates are much lower at older ages. In the UK, it is only 8 per cent among people aged 65+. This still implies a difference - and it is certainly striking that decades of smoking don't make people more likely to be hospitalised with this respiratory disease - but claims based on unadjusted figures are bound to exaggerate any protective effect.

This is why it is better to focus on the relatively small number of studies that use epidemiological methods and adjust for other factors. There are not many of them, but it has to be said that their results are fairly consistent.

Let me know if I am missing any, but I can find six...

1. This recent study from Israel involved testing 114,545 people for the virus. The smoking rate was 9.8% among those who tested positive (the national rate is 19%). After adjustments, the authors found that smokers were half as likely to test positive, with an odds ratio of 0.46 (0.41-0.51). This is, as the authors conclude, an 'intriguing finding' which 'may reveal unique infection mechanisms present for COVID-19 which may be targeted to combat the disease and reduce its infection rate.'

2. That is very similar to this British study which found that 'active smoking was linked with decreased odds of a positive test result' with an odds ratio of 0.49 (0.34–0.71).

3. This British study found that smokers were 27% less likely to test positive for COVID-19 although you have to look carefully to find the evidence because the lead author is the chairman on Action on Smoking and Health and he buries it as much as he can. The odds ratio is 0.73 (0.65-0.81).

4. Meanwhile this British study looked at the likelihood of dying from COVID-19 and found that smokers were slightly more at risk, or slightly less at risk, or neither, depending on how the figures were adjusted.

5. Then there is this study from the USA which looked at 3,789 US military veterans aged between 54 and 75 who were tested for COVID-19, of whom 585 tested positive. Smokers were 55% less likely to test positive, with an odds ratio of 0.45 (0.35-0.57).

6. Finally, there is this study from a badly hit area of France where 661 people were tested for COVID-19 and smokers were 67% less likely to test positive. Odds ratio after adjusting for age: 0.23 (0.09 –0.59).

With the exception of the Goldacre study, all of these look at the likelihood of testing positive for the virus, not the probability of being hospitalised or dying from it.

There are dozens of other studies and datasets showing a low proportion of smokers among Covid hospital patients, but these studies do not specifically look at the question of smoking's effect on the virus. In many cases, the authors do not even comment on the rate of smoking, and in some of them the rate of smoking is not particularly low anyway.

If smokers are less likely to be hospitalised with the coronavirus, it could be because smoking/nicotine makes symptoms less severe or it could be because smokers are less likely to get it in the first place.

The original hypothesis put forward by Konstantinos Farsalinos lent towards the former explanation, but I tend to lean towards the latter because there are studies adjusting for other factors, crucially age and sex, which back it up. In addition, there are several other studies which do not produce odds ratios, but which strongly suggest protection against infection, such as this, this and this.

All in all, the evidence that smoking reduces the chance of a person testing positive for the virus is methodologically stronger than the evidence implying that smoking helps combat the disease once a person is infected. From the evidence above, one might tentatively conclude that smoking reduces the risk of infection by 50 per cent.

But there is one thing that has been bugging me about this theory for weeks. A lot of the evidence showing low rates of smoking among patients comes from China where the smoking rate is 27%. That figure masks a huge gender divide, with 52% of men smoking and only 3% of women. The official figure for women is probably an underestimate as there is a certain taboo about women smoking in much of Asia, but there is nevertheless a very large gap in prevalence between the two genders.

Therefore, if smoking confers some sort of protective effect, we should expect to see men enjoying a disproportionate benefit. Do we see that in the statistics for testing and hospitalisation? Not really, no. Men tend to be slightly over-represented in Covid wards.

However, we also know that men are more likely to be hospitalised and die from COVID-19 - twice as likely in some studies. (We also know, although it won't have a big impact on these statistics, that there are more men than women in China as a horrible consequence of the one child policy.)

So the real question is whether China has a smaller proportion of men with COVID-19 than countries that have a more equal distribution of smokers across the sexes. The evidence must be out there, but I have yet to find anything conclusive.

Looking at the studies that have crossed my radar while looking at the smoking hypothesis, here's some evidence for China. I include only relatively large studies involving more than 100 patients/cases:


Large study of 1,056 COVID-19 cases in China found that 536 (50.8%) were male.

Study of 585 confirmed cases in Beijing found that 268 (45.8%) were male. No smoking history recorded.

Study of 292 patients in China found that 50.7% were male. The smoking rate among the patients was just 5.1%, although smokers were more likely to be classified as 'severe' than 'mild'.

Study of 285 patients in China found that 128 (44.9%) were male. 11% of the patients were smokers.
 
Study of 276 patients in the Zengdu District found that 56.2% were male. 12.8% of the total had a smoking history.

Study of 202 patients in China. 107 (51.4%) were males and 101 (48.6%) were females. 5.8% had a history of smoking.

Study of 200 patients in Wuhan found that 99 were male (49.5%). Unusually, most of them were smokers, although 'no difference on the fatality rate of COVID-19 patients was found between smokers and nonsmokers'.

Study of 143 patients in Taizhou, China found that 77 were male (53.8%). 9.8% had a history of smoking (see table - text is wrong) and smokers were no more likely to suffer severely than nonsmokers.

Study of 134 patients from 9 cities outside Wuhan found that 65 (48.5%) were male. 10.4% were smokers.

Study of 121 patients in Wuhan found that 66 (54.6%) were male. 5% were current smokers. 

Study of 101 Chinese medical staff infected with COVID-19 found that 32 (31.7%) were male. Only four were smokers. However, what proportion of Chinese medical staff are female?

I've also looked at the larger Chinese studies previously mentioned in this blog post. The numbers are:

Guan (1,099) 58% male

Shi (487) 53% male

Zhou (191) 62% male

Zhang (140) 51% male

Wan (135) 53% male

Liu (78) 50% male

From this sample of studies, the gender balance is not far off 50/50, with several studies showing a majority of women. Of particular interest are the two large studies at the top because they show cases rather than patients (ie. people who have tested positive but are not necessarily hospitalised). Taking those two sets of numbers together, a slight majority of 51% of cases were women.

How does this compare to countries where there is less of a gender gap in smoking rates? It's not easy to say, but here are the results from the largest of the studies I have come across. The figures refer to COVID-19 hospital patients unless otherwise noted.


Various countries (8,910 patients of whom 1,507 were in China) 59.6% male (5.5% were smokers)

UK (8,699 patients) 71.1% male (smoking data not included)

UK (7,346 patients) 60% male (number of smokers is unclear)

New York (5,700 patients) 60.3% male (15.6% had history of smoking)

UK (5,683 deaths) 63.1% male

New York (4,103 patients) 50.5% male (5.1% were current tobacco users) 

New York (1,999 patients - same study as above) 62.6% male (5.2% were current tobacco users)

Sweden (2,158 ICU patients on 3 June) 74% male

USA (1,482 patients) 54.5% male (smoking data not included)

Italy (441 patients) 61.9% male (4.8% were smokers)

New York (393 patients) 60.6% male (5.1% were smokers)

Switzerland (200 patients) 60% male (4.5% were smokers)

In all of these studies, the majority of patients were male. In most of them, at least 60% were male. By contrast, in the Chinese studies above, only one had a male rate above 60%.

Perhaps this is telling, but unfortunately all of these studies look at patients, not cases. Global Health 50/50 has the gender breakdown of cases for various countries, but there is no clear pattern. In some, such as Pakistan and Ecuador, there are more men. In other, such as Sweden and the Netherlands, there are more women.

I'm not sure what to make of this. I only mention it in the hope that somebody will pick up the gauntlet and find something more conclusive. But it seems to me that for the smoking hypothesis to be correct, we should be seeing disproportionately few cases among groups in which the smoking rate is high (eg. Chinese men). If such an effect is not apparent from the aggregate data then any positive effect from smoking/nicotine is either non-existent or too small to get excited about.

Wednesday, 3 June 2020

Restricting the sale of high strength beer and cider doesn't work

One of the pet projects of England's overpaid public health directors is getting shops to stop selling high strength beer and cider. Alcoholics and/or street drinkers are known to favour these products and so, in the stunted imagination of paternalists, it is assumed that there will be fewer alcoholics and street drinkers if they are removed from the market. It is exactly the same logic that lies behind minimum pricing.

More worldly people argue that these people will substitute other types of drink (or drugs) and that such policies will, at best, make them even poorer.

Nevertheless, many shopkeepers have gone along with these schemes and their local implementation has created some natural experiments.

Two years ago, I mentioned a study looking at the Reduce The Strength initiative in Suffolk which concluded that 'the overall findings showed no intervention attributable impact.'

Our findings suggest that voluntary RtS [Reduce The Strength] initiatives, have little or no impact on reducing alcohol availability and purchase amongst a broader population of customers.

Brighton and Hove has a similar campaign called Sensible on Strength which has led to more than 200 off-licences (74%) no longer selling high strength beer and cider. A new study looks at the alcohol consumption and health outcomes of people admitted to hospital with liver disease in the city.

The study is called 'Does regulating the sale of high-strength beer and cider impact hospital admissions with decompensated alcohol-related liver disease?'. The answer is no. The individuals consumed less beer and cider after Sensible on Strength began but they consumed more wine, and there was no change in their overall consumption of alcohol. Nor was there any change in rates of alcohol-related liver disease (ALD) mortality after the scheme took effect.

Comparing patients admitted in both phases, there were no significant differences in liver prognostic scores, liver-related complications, length of stay and inpatient/long-term mortality (p>0.05). However, the SoS initiative was associated with a 33% move away from beer and cider consumption (36.3% vs 54.0%; p=0.034), but without a significant change in units of alcohol consumed.

Awkward.

Though there was a 33% reduction in the consumption of beer and cider post introduction of the SOS initiative, the total number of alcohol units consumed did not change. This might explain why the SOS initiative did not impact the number and severity of hospital admissions with ALD [alcohol-related liver disease] nor have an effect on ALD-related mortality.

D'ya think?

'Public health' academics can never fully admit defeat so they conclude by saying that their study shows that 'regulating alcohol sales can modify drinking behaviour' and conclude as follows:

Despite having no apparent impact on the clinical spectrum of local ALD admissions, it is conceivable that longer follow-up is needed to determine the true impact of this initiative.

Hmm. Since the scheme didn't lead to a decline in alcohol consumption, I wouldn't get your hopes up for that.

Beer and cider sales down, wine sales up, and no improvement in health outcomes? There are obvious parallels here with the minimum pricing flop.

Tuesday, 2 June 2020

Alcohol prohibition relaxed in South Africa, tobacco prohibition continues

People in South Africa were finally allowed to buy alcohol yesterday, and there was much rejoicing.



The government is maintaining the prohibition on tobacco, however. Its Covid-related excuses for doing so are threadbare and I suspect the state has simply seized an opportunity to experiment with 'endgame strategies', as tobacco prohibitionists euphemistically call them.

There are no prizes for guessing how this will work out, but expect to see some 'studies' in the likes of Tobacco Control saying what a success it's been.

I've written about lockdown prohibitions in South Africa and elsewhere for Cap-X.

Students of history will not be surprised that certain criminal activities have soared under South African prohibition. Fully stocked liquor shops have been sitting ducks for looters and armed robbers while criminal gangs have been bringing contraband alcohol over the country’s notoriously porous borders.  

Do have a read.

Monday, 1 June 2020

The Global Forum on Nicotine goes online

The Global Forum on Nicotine is normally held in Warsaw in mid-June. I've been a number of times and it is great event with some excellent speakers discussing vaping and tobacco harm reduction.

This year, for obvious reasons, it is shifting online. It's free to access and open to all, so register here.




Saturday, 30 May 2020

Trump defunds the WHO - not a moment too soon

Looking good!

The World Health Organisation has had a lot of heat on it recently, never more so than today, after Donald Trump announced that he was pulling the USA out of it and diverting its $400 million to more worthy causes.

Anyone expecting to hear a response from the WHO on its Twitter feed will be disappointed. Instead, it has gone off on a mad one about smoking.


The answer is Stranger Things, a programme that is not suitable for children, but not because of the smoking 'incidents' (they mean incidence).



The real answer is none of the above. It is retailers that sell tobacco to the public, not the tobacco industry - and shops don't sell tobacco at a child's eye level. Nor is it sold near chocolate, sweets and fizzy drinks, for that matter, but given the WHO's view of chocolate, sweets and fizzy drinks, perhaps it should be.

You can expect more of this garbage in the next 36 hours as the WHO retreats from the awkward conversations about COVID-19 and settles into the warm bosom of World No Tobacco Day. This year it is focuing on - surprise, surprise - vaping. It has even created some snazzy images to make e-cigarettes appealing to children.

I'd be the first to admit that it's difficult to make vaping look cool, but they've done it. Nice one, WHO!






Last Orders with Matt Ridley

There's a new episode of the Last Orders podcast out with Matt Ridley in which we talk about innovation, the lockdown and prohibition. Give it a listen.