Covid-19 and the Culture War over “Herd Immunity”

 While the details are extremely complex, most people understand the general principle of immunity to disease in individuals and that two of the main ways in which immunity can be acquired are through vaccination or “natural” exposure-to-an-infectious-agent-that-does-not-result-in-death. Arguments tend to be about how good, and how long lasting, such immunity might be in the case of the SARS-CoV-2 virus (responsible for Covid-19 infections), and that is something we just do not know yet.

The notion of immunity within a population (or “herd”) is a more imprecise notion which seem to be at the heart of a burgeoning culture war on social and traditional media.

Let us try and unpick the various issues:

We do not need to speculate too much about what happens when contagious disease (i.e. disease that spreads from person to person) disperses unchecked through a population with no immunity because we have plenty of examples within living memory.

Prior to 1954, measles might arrive in a small relatively isolated community and spread rapidly through it. Some individuals might die, others might suffer serious injury[i], but most would recover and most of these individuals would thereby acquire immunity to the measles virus – immunity that would usually (though not always) remain with them for the rest of their lives.

What is of note here is that the measles virus would not necessarily need to infect every individual in the isolated community before cases of measles disappeared in that community. Measles is highly contagious, but once a certain threshold of immunity (around 91-94%[ii]) is reached within a randomly mixing community[iii], the virus will normally cease its spread and disappear from that community.

The 6-9% who never became infected are now safe – protected by all those who did become infected and survived. Moreover, even if a new infected person arrives in the community, it is unlikely (though obviously not impossible) that they will pass on their infection to anyone in the community.

The protection (such as it is) from measles for that isolated community may last for a generation, but as more and more people die of old age and more and more new children are born without immunity, that community protection weakens. Eventually, a new epidemic of measles will devastate the community.

This is one reason why infections may come in waves.

Those bad old days are behind us and, pace the activities and influence of various anti-vaccination fanatics, we can achieve 90% or more immunity against measles across a population by vaccinating everyone we can.

So far so good, and we have not even mentioned the boo term yet …

Mass vaccination is the context in which the term “herd immunity” (AKA “community immunity”) is most often encountered these days, but, as this definition from the Centers for Disease Control and Prevention makes clear, use the term is not restricted to immunity that is acquired from vaccination programmes:

Community immunity: A situation in which a sufficient proportion of a population is immune to an infectious disease (through vaccination and/or prior illness) to make its spread from person to person unlikely. Even individuals not vaccinated (such as newborns and those with chronic illnesses) are offered some protection because the disease has little opportunity to spread within the community. Also known as herd immunity.

But even this definition leaves some loose threads untied. As Fine, Eames, and Heymann have put it[iv]:

The term “herd immunity” is widely used but carries a variety of meanings. Some authors use it to describe the proportion immune among individuals in a population. Others use it with reference to a particular threshold proportion of immune individuals that should lead to a decline in incidence of infection. Still others use it to refer to a pattern of immunity that should protect a population from invasion of a new infection. A common implication of the term is that the risk of infection among susceptible individuals in a population is reduced by the presence and proximity of immune individuals (this is sometimes referred to as “indirect protection” or a “herd effect”).

To illustrate the three usages using the measles example:

1.   An example of “herd immunity1” might be “There is only 80% herd immunity against measles in the UK at the moment and that is too low.”

2.   An example of “herd immunity2” might be “Cases of measles will only start to decline towards zero in the UK once 90%+ of the population have been vaccinated (or have recovered from the illness) and herd immunity is achieved.”

3.   An example of “herd immunity3” might be “An epidemic of measles in Finland would be impossible because of the level of herd immunity there achieved through high MMR uptake.”

I should argue that usage “3” overlaps with “1” and “2”, but this is all getting a bit pedantic. I think we can make do with the “common implication of the term” that “the risk of infection among susceptible individuals in a population is reduced by the presence and proximity of immune individuals” and all agree that that is true.

I do not see any good reason for a culture war over terminology here!


So what about the SARS-CoV-2 virus? (I hear you all cry.)

There is still huge uncertainly about Covid-19. All scientists can do as we look ahead is to use complicated mathematical models to predict what might happen given certain assumptions.

Inputs to these models are things like how many people currently have Covid-19; how long they remain infectious; how many people they each infect; how likely they are to die and in what time-frame; and, yes, how many have recovered from and infection and thereby (it is to be hoped) gained immunity.

I say “it is to be hoped” because, as is often pointed out, the immune response that defeated the virus in a particular individual may not persist, or a new strains of the virus may evolve against which immunity previously acquired is no longer effective.

There is, I should wish to contend, a growing body of evidence that the people who gleefully point these things out are being unduly pessimistic. But time will tell.

On the other hand, there is (putting my pessimist’s hat back on) growing evidence that a lot of people who “recover” do not fully recover from Covid-19[v].

So, as an earlier famous Vladimir had it: “Что делать?” – “What is to be done?”.

It is strange – I often reflect – that someone’s views on our trade relationships with other European countries should be such an accurate predictor of their views on virology. But this seems to be very much the case.

There is a vocal body of people on social and traditional media who argue (alongside venting their spleen at the Belgians or whoever) that we should moderate or abandon our efforts to control the spread of the virus and let nature take its course. Such people often use the term “herd immunity” to describe the happy state that would emerge after the “unfortunate deaths of a few old people who would have died soon anyway”.

Other people appalled (rightly IMHO) at such a suggestion often seize on the term “herd immunity” and seem to have invented yet another definition:

  1. “herd immunity4”: “The belief that we should accept the death and disability of hundreds of thousands of people with equanimity.”


But do the more moderate members of the let-nature-take-its-course brigade have a point? Could we somehow arrange for everyone who would fully recover from Covid-19 infection to be infected while protecting all the more vulnerable people?

The short answer is “no!”.

The slightly longer answer is that if let Covid-19 spread freely across the globe (with or without attempting to protect people we assume are most at risk of death or disability) far too many people would end up dead or disabled – including perhaps people even "lockdown sceptics" care about.

The slight caveat here is that we are currently allowing as much normal activity as we feel is safe to allow at any one time and thus striking a balance between risks to vulnerable people and other considerations – including risks to people who are vulnerable to non-Covid related dangers[vi]. In doing this, it is, I submit, often reasonable and ethical to try and decrease risks to the more vulnerable even where this increases risks to the less vulnerable.

It is not wrong or evil to point out that there are, sadly, always difficult trade offs to be made in life.

In the meantime all we can do is try and get a test and trace system in place that actually works, continue our social distancing, continue targeted social measures – which will inevitably involve a lot of trial and error – and hope for a vaccine as soon as possible.

[i] Which is why everyone should vaccinate their children with the MMR jab.

[iii] Of course, real communities do not mix entirely randomly.

[v] https://www.bmj.com/content/370/bmj.m3489

[vi] Listen to https://www.bbc.co.uk/programmes/m000mt1l for a rather harrowing report on the plight of women having babies in our current situation.


Brexit. What happens next?

A (tidied-up) Twitter thread which seems to have broken in two on the site.

It's been interesting listening to @BBCr4today recently because they're actually doing what they should have done[i] before the referendum (and subsequently) and trying to examine our various options outside the EU and what they imply.

But, as ever, it is very difficult to read the runes as to where we are really going.
I suppose the EU will view Raab's insistence that following EU rules after 2021 "just ain’t happening" as it now views May's insistence that a customs border within the UK (between GB and NI) was something "no U.K. Prime Minister could ever agree to".

Raab, of course, is delusional (and ill-informed) enough to really mean this, but what Johnson (who will make the actual decisions …. with a little help from his friend Dom) will decide cannot be gleaned from anything he says now.

Either way, we now seem to be heading for a very hard Brexit indeed - with a regulatory and customs (and possibly a tariff and quota) border between GB and the EU (and between GB and NI).

One problem is highlighted by the UK government's former insistence on calling the "transition" period the "implementation" period - something which seems to have been quietly dropped "in real life" but which can still be found on their website:

The difficulty here is that nothing that could be implemented has been agreed yet and, once it has been agreed - presumably towards the end of 2020, there will be no time to implement any of the agreed new procedures.
But - if anything the UK government are saying is to be taken at face value (not necessarily a given) - we are, at best, going to need significant new border and compliance infrastructure: sheds, waiting areas, IT, customs brokers etc and, at worst, even more of such things. There is no sign that the UK government is making any such preparations in a serious fashion.

We have, of course, been here before; except this time around, we head towards a cliff edge locked into an international treaty that protects (some) citizens' rights; enforces a customs border down the Irish Sea; and mandates us to pay the EU a lot of money.

In other words, these issues can no longer be used as the basis of threats against the EU. They never increased the strength of the UK's hand greatly anyway, but agreeing them has weakened that hand still further.

In the meantime we can predict (with reasonable confidence):
  • Increased fulminations from the DUP in NI, as the true consequences of Johnson's WA dawn on them (though they have painted themselves into a corner and have nowhere else to go).
  • The rest of EU manufacturing continuing to prune the UK from its supply chains.
  • UK manufacturing (especially car manufacturing) to continue  slowly dismantling itself and moving away.
  • A continuing decline in the numbers of Drs, nurses, midwifes, care-workers, agricultural workers, top academics etc coming here from the EU - perhaps combined with a last minute rush of EU citizens coming here before the drawbridge in drawn up at the end of the year.
  • Continued remonstrations from industry about the lack of any clarity when it comes to the details of what they will have to prepare for.
  • & c

None of these (and similar processes) will dent the faith of the true believers who, let's face it, are essentially like a millennial cult. Even a severe recession and chaos at our ports would not dent their faith. They would just blame the EU and insist that Brexit needed to be even harder.

I suppose the key agreement we need to look out for is one on fish [sic]. Everything that has happened thus far would seem to point to Johnson betraying the UK fishing industry (as he did the DUP) and agreeing to the EU's terms (albeit with some cosmetic concessions from the EU.)
As with the DUP, our tiny fishing industry - having made its bed - will just have to lie in it.  Fishing is supposed to be one of the issues that is agreed quickly - though it would be in both sides' interest to keep any agreement hidden from view for as long as possible.

If Johnson capitulates to the EU on giving them access to our waters in return for giving our fishermen/women access to the EU market (the only sensible course of action) perhaps he will soften on other matters too. If he stands firm, we are looking at very troubled waters ahead.

[i] Pace the preposterous over-promotion of Nigel Farage's views, there was actually a pretty fair balance of opinion throughout on @BBCr4today; and we should recognize and cherish that fact. There was, however, an appallingly skewed imbalance of uninformed perceptions versus facts (or at least informed commentary).


A Belgian Letter

This was a letter recently sent to Guy Verhofstadt by Brandon Lewis (Minister of State for Security and Deputy for EU Exit and No Deal Preparation). He recently re-tweeted a link to his missive:

and I thought inclined to point out its inaccuracies:
(My comments are in dark blue.)


Guy Verhofstadt
Member of the European Parliament
Brexit Co-ordinator and Chair
Brexit Steering Group
European Parliament Office
1047 Brussels
13 September 2019

Dear Guy,


I saw your tweet on 11 September claiming that Home Office treatment of EU27 citizens is unacceptable and settled status isn’t working. I wanted to write to put the correct position on record, and to express my disappointment and frustration that there continues to be misunderstanding about the EU Settlement Scheme.

There is no misunderstanding. The EU Settlement Scheme is very well understood by Guy and his colleagues in the European Parliament.

Such misconceptions, along with inaccurate press coverage, undermine the reassurances we are seeking to provide to EU citizens in the UK, generate uncertainty and cause unnecessary worry and stress for individual citizens.

In the UK, approximately 80% of the press (by readership)[i] is pro-Brexit. The current UK government would seem to be in a weak position when it suggests that its reassurances on Brexit have been undermined by the UK press. And there has been no suggestion that Die Welt misreported Mr Lewis’s affirmative answer to their question about whether people who meet all the conditions for settlement but fail to apply in time will be deported[ii]. That statement has certainly caused a lot of worry for EU citizens.

Above all, the UK Government wants to reassure EU citizens in the UK that they are welcome to stay and that we are committed to protecting their rights. Even if we leave the EU without a deal, the Prime Minister has made clear that EU citizens living in the UK will have the absolute certainty of the right to live and remain.

It is hard to reconcile this statement with the repeated votes in Parliament to deny EU citizens their rights[iii]

or with Theresa May’s characterization of EU citizens as “queue jumpers”[iv]

or with the refusal of our PM to honour the promises he made during the Brexit campaign that there would be no change for EU citizens lawfully resident in the UK; that such citizens would be automatically be granted settlement; and that they would be treated no less favourably than at present[v]

or with Johnson’s recent complaint that EU citizens “treat the UK as if it's part of their own country”[vi].

Far from “protecting” the rights of EU citizens, the UK government is abolishing their existing status as of 2020 January 31 and forcing them to apply for new reduced rights. There is no certainty – “absolute” or otherwise. Some applicants are being turned down outright[vii] and 43% are only being granted pre-settled status. Citizens who successfully obtain settled status will thereby obtain the right to “live and remain” in the UK – providing they do not go abroad for too long, in which case they will lose their status – but they will lose other important rights and some of their ability to enforce their rights[viii]. Their rights and the protection of those rights would be further eroded by a “no deal” exit from the EU.[ix]

We have launched the EU Settlement Scheme to give EU citizens their rights in UK law, to ensure that they can continue living in the UK after we leave the EU – deal or no deal. The scheme is set out in Immigration Rules made under the Immigration Act 1971. The status granted under the scheme – settled status (indefinite leave to remain) or pre-settled status (five years’ limited leave to remain) – is a status under UK immigration law and will guarantee the person the same access to work, study, benefits and services as they currently have under EU law on free movement.

As noted above, the EU Settlement Scheme does not “give EU citizens their rights”, it takes some of them away (if applied for successfully), and all of them away (if an application is refused). Moreover, the EU Settlement Scheme does not guarantee the same access to benefits and services as they currently have[x] and the government has recently legislated to take away some entitlements to benefits from EU citizens with pre-settled status[xi].

The secure evidence of that UK legal status which the EU Settlement Scheme also provides will ensure that, years from now, EU citizens and their family members can continue, easily, to prove their status and exercise the rights and access the entitlements which, deal or no deal, are protected.

“The secure evidence” is a digital code which EU citizens who successfully apply for settled status will be given and which potential employers, landlords, NHS staff etc will have to enter into a web site in order to establish the legal status of EU citizens they deal with. No physical card or document will be issued, and this was a key criticism in the Home Affairs Committee report on the Scheme[xii].

The facts are that the EU Settlement Scheme is working well. More than 1.5 million people have now applied, according to our internal figures, and by the end of August more than 1.1 million applicants had been granted status under the scheme. There is plenty of time to apply – until at least 31 December 2020 – but we are keen for people to apply as soon as possible and will shortly be renewing our communications campaign, with a particular focus on supporting the vulnerable.

Tens, or even hundreds, of thousands of vulnerable EU citizens (who may have lived in the UK for decades) are going to miss the December deadline and thereby become liable for incarceration and deportation.[xiii]

There has been much media speculation about grants of pre-settled status, including allegations that we are deliberately seeking to grant pre-settled status to people who are eligible for settled status. I would like to emphasise that nobody has been granted pre-settled status without first being offered the opportunity during their application to submit evidence that they qualify for settled status.

This is a complex issue and there is a dearth of hard information with which to construct an overview of what is actually going on. There have been stories in the newspapers about individual cases when deserving – and apparently highly competent people – have failed to obtain the correct status[xiv] but, since the Home Office have thus far avoided collecting any data that would show how many people expecting to get the full status failed to do so, it is difficult to know how representative the cases in the press are of a general problem. That being said, in 2018 December, the Home Office change the interface to include the following question:

The Home Office’s decision to start asking this question would seem to suggest that – pace Lewis’s remarks – the UK government have accepted that there has hitherto been a problem.

Pre-settled status aligns with EU law whereby someone generally only acquires permanent residence status after five years’ continuous residence. As soon as EU citizens and their families have accrued five years’ continuous residence, they can apply for settled status, which gives them leave on an indefinite basis. The proportion of those being granted settled and pre-settled status is broadly in line with expectations, based on the Annual Population Survey figures for the UK’s resident EEA population.

It is odd that Lewis seeks to justify UK policy by appealing to EU law. It is usually emphasized that one of the main aims of this whole exercise is to assert the supremacy of UK law[xv]. There is no reason why a more generous offer could not have been made to EU citizens who have not lived here for five years, or who have but are unable to evidence this fact. The insistence on only awarding pre-settled status ensures that there will be more problems in five years’ time when hundreds of thousands will have to re-apply.

If any EU citizen feels they or their family member have erroneously been granted pre-settled status – or if they need help with any other aspect of their application – I would encourage them to call our dedicated helpline 0300 123 7379. It is open seven days a week and there are hundreds of staff standing by, ready to assist with queries.

The provision of a dedicated helpline is one of the few positive aspects of the settlement scheme, and perhaps the Home Office might consider its extension to help EU citizens applying for UK citizenship or with other immigration problems. This facility has not, however, been without problems[xvi].

I hope you can agree that the arrangements described in this letter honour the obligations and commitments the UK Government has made in respect of citizens’ rights, including safeguarding the employment status and social entitlements of EU citizens resident in the UK.

The arrangements described in this letter certainly do not honour the commitments made by three key members of the UK Government: Boris Johnson, Michael Gove, and Priti Patel. On paper, the arrangements described in this letter do honour the obligations and commitments the UK Government has made in respect of safeguarding the employment status of EU citizens, but, deprived of a physical document with which to evidence their status, there are many reasons to think that, in the real world, employers will discriminate against EU citizens. The arrangements described in this letter do not honour the obligations and commitments the UK Government has made in respect of the social entitlements of EU citizens resident in the UK.

I trust you will be urging the EU27 to adopt similarly generous approaches that will provide UK nationals in the EU27 with the certainty and security that they need. It would be good to see the EU27 matching our offer of a fee free process and a deadline of at least 31 December 2020 for UK nationals to secure their status.

This is probably the most disingenuous paragraph in the whole of Lewis’s letter. It is the UK that is stripping its own citizens of their EU citizenship and thus their rights in the EU/EEA. This means that, by default, UK citizens in the EU/EEA are left at the mercy of whatever rules each member state has for third-country immigrants.

Imagine that (say) Australia withdrew from the Commonwealth. Australian citizens living in the UK would, thereby, lose certain rights here – such as the right to vote (a privilege denied to EU citizens). Now imagine how the UK Government and our newspapers would react if Australia began lecturing us about our treatment of their citizens. They would say to Australia “this was your choice”; and that is what the EU and its members will say to us.

Having said all that, the EU could require its members to grant uniform privileges to UK citizens after Brexit, if all those members voted for such arrangements, and the UK could have tried to negotiate for this as part of the withdrawal agreement with the EU. The EU was open to this and originally argued that all citizens (EU in UK and UK in EU) should retain all their existing rights. Unfortunately, it was more important to the UK to deprive EU citizens in the UK of their rights than it was to protect the rights of our citizens living in the EU. Given the principle of reciprocity (which both sides agreed to) we are where we are, and we simply have to hope that all the individual EU member countries will be more generous towards our citizens than we have been towards our citizens who made the grave mistake of exercising their freedom to live, work, study, and fall in love in another part of our continent.

Minister of State for Security and Deputy for EU Exit and No Deal Preparation


Steve Peers (@StevePeers Professor of EU, Human Rights & World Trade Law, University of Essex) has just brought my attention to the fact that Lewis has also got the date wrong here. And, following from that error, he has got his facts wrong in another way too.

Assuming Brexit goes ahead with Johnson's "new" (Withdrawal Agreement (WA)  - which is all but certain now - EU citizens in the UK and UK citizens in the EU will have until six months after the end of the "transition" period - i.e. until at least June 2021 to apply for settlement under the terms of the WA! In other words, Lewis's call for the EU to match our offer of a "deadline of at least 31 December 2020" is completely nonsensical.

Lewis is, however, correct (as I understand it) that some (or all?) EU countries have (modest) charges in place for UK citizens now forced to apply for residency in those countries as the UK originally insisted on for EU in UK. Again, the UK government could have easily tried to negotiate free schemes for all had it been so inclined at the time, but this would have meant the UK putting the plight of its own citizens above its desire (at that stage in the proceedings) to penalize EU citizens.

[ix] This is all a rather complicated area. The main loses of rights relate to absences from the UK (for example to study, work, or care for a family member abroad); rights to use a national identity card rather than a full passport; rights to family reunion; reduction of the criminality threshold (so that what were hitherto considered more minor offences may lead to deportation or refusal of status in future); and loss of certain appeal/enforcement rights. See eg Citizens’ Rights - EU citizens in the UK andUK nationals in the EU (Policy Paper).
[x] Again this a complex area (see eg How canEU nationals access UK benefits?). Those granted “pre-settled” status would seem to be a in far more precarious situation with respect to obtaining benefits than those granted full “settled” status. It should be noted that, hitherto, the UK has been more generous to EU citizens than a strict implementation of “EU law” would have required. The implication of Lewis’s remarks would seem to be that this generosity will end. Lewis masks this issue by his use of the phrase “the same access […] as they currently have under EU law on free movement” which sounds like “the same access […] as they currently have”, but isn’t the same.
[xiii] See Has the Government learned from theWindrush scandal? In the Home Affairs Committee report for discussion of this issue.