Let us be clear from the start: the case, the whole case, and nothing but the case for the introduction covid vaccine passports rests on a single premise: that covid vaccination reduces the risk of onward transmission of covid–19 by vaccinated individuals. That is the alpha and the omega in the Empire of the Covid Passport Tsar. If folk, be they vaccinated or unvaccinated, are as likely the catch covid from a vaccinated individual as they to catch it from an unvaccinated individual, then there is no case for covid vaccine passport. The Covid Passport Tsar has no clothes, and more importantly, he has no evidence, and stands revealed as the model tyrant from Albert Camus’ 1950s observation: ‘Le bien-être du peuple en particulier a toujours été l’alibi des tyrans, et il offre de plus l’avantage de donner bonne conscience aux domestiques de la tyrannie‘ (The well-being of the people in particular has always been the alibi of tyrants, and it offers the additional advantage of giving the servants of tyranny a good conscience).

There are two factors we need to consider when we consider the risks of covid transmission by the vaccinated and the unvaccinated. The first is how likely are vaccinated people to get infected, compared to unvaccinated people. Even if the risk of transmission by an individual remains the same, if there are less infected people in a room full of vaccinated people compared to a room full of unvaccinated people, then, other things being equal, the number of secondary infections will be lower in the room full of vaccinated people. Let us for convenience call this susceptibility. The second factor we need to consider is transmissibility, the risk of an infected person transmitting the infection to another individual. It could be the case, for example, that both the vaccinated and unvaccinated are equally susceptible, but the vaccinated are less infectious, and so transmit less infections. Or not. We need some evidence.

The susceptibility question — are vaccinated individuals more or less susceptible to covid infection — is relatively easy to answer. For the past several weeks, UKHSA’s regular vaccine surveillance reports have shown that vaccinated individuals are more likely to be infected with covid than unvaccinated individuals. Putting aside UKHSA’s increasingly desperate explanations as to why their own data couldn’t possibly be right, the latest report shows that, in most age groups (18 to 69 years olds), vaccinated people are about twice as likely to be PCR positive than unvaccinated individuals. Imagine two huge supermarkets, one full of 10,000 vaccinated individuals, the other full of 10,000 unvaccinated individuals. The vaccinated supermarket will have within it very roughly, using back of the envelope averages, around 230 infected individuals, while the unvaccinated supermarket will have 122 infected individuals. Your chances of not getting infected are better in the unvaccinated supermarket. As a sanity check, these numbers are broadly in line with ONS’s contemporary prevalence estimates of around one in 50, or 2%, of the population, or 200 of 10,000 people, being infected.  

The transmissibility question — are vaccinated individuals more or less likely to transmit covid — is a whole lot more tricky to answer, because it needs sound epidemiological work to get an answer. Ideally, we want a cohort study: a cohort of the vaccinated, matched to unvaccinated controls, who are then followed up to determine not just who get infected, but then how many people the infected then go on to infect. It means doing a lot of PCR tests on a lot of people, regardless of symptom status, so you track asymptomatic as well as symptomatic infections, as well as thorough contact tracing, with follow up to see whether they get infected. Such studies are not for the faint hearted, which is why they are rare, but they have recently started to appear, with two being of particular interest.

The first study, published in early November, but using earlier data from September 2020 to May 2021, was done in Singapore, a near ideal setting for such a study, given Singapore’s island city-state status, and the rigour of its quarantine and contact tracing habits. It explicitly set out to determine the ‘Impact of …Vaccination on SARS-CoV-2 Secondary Attack Rate Among Household Close Contacts’ using a retrospective cohort design. It did find a modest vaccine effect against delta acquisition (ie any PCR positive result, whether the individual was symptomatic or not), with a vaccine effectiveness of around 60% (60% fewer exposed individuals will get infected), which is at odds with UKHSA’s current rates, but there you go. But what about the secondary attack rate by index case vaccination, the finding we want from this study? Here, the study reports an adjusted odds ratio of 0.73 in favour of vaccination, but the confidence interval is wide (0.38 – 1.40), and includes 1, leaving the authors no alternative but to conclude that ‘Close-contacts of vaccinated Delta-infected indexes did not have statistically significant reduced risk of acquisition compared with unvaccinated Delta-infected indexes’.

The study, though commendably thorough in both testing and contact tracing, is inevitably plagued by small numbers, meaning low statistical power, and so a compromised ability to detect a small but true difference. Nonetheless, we are where we are, and this study shows no statistically significant difference in transmission between vaccinated and unvaccinated index cases. A larger study with greater statistical power might — or might not, we just don’t know — have detected an effect, but it is highly unlikely that any such result would be a world shattering result that would put lead in the Covid Passport Tsar’s pencil. As things stand, the case for covid passports has not been made.

The second study was broadly similar to the Singapore study, but was conducted in England. Published in late October 2021, it too used a cohort design, and reasonably thorough (England is not Singapore…) PCR testing and contact tracing to, among other primary objectives, ‘assess the secondary attack rate (SAR) in household contacts stratified by contact vaccination status and the index cases’ vaccination status’. We have what we need: a cohort design, with a primary objective of determining secondary attack rates in close contacts by index case vaccination status. The study covers a longer period that the Singapore study, September 2020 to September 2021, but only managed to recruit a fraction of the number of close contacts, hundreds rather than thousands, despite an order of magnitude difference in population size, which does raise questions about how representative the sample was.

But, again, we are where we are. As in the Singapore study, the English study found a modest point estimate for a vaccine effect in preventing infection in the vaccinated, but this time it was not significant (vaccine effectiveness estimate for any infection, both symptomatic and asymptomatic, 34%, 95% CI a rather eye watering -15 to 60). The secondary attack rate by index case vaccination status (the chances of a vaccinated individual, compared to an unvaccinated individual, transmitting covid to a household contact) was marginally higher for vaccinated individuals, at 25%, compared to 23% for unvaccinated index cases, but of course is not statistically significant: in other words, there is, on the basis of this study, no difference in transmission from vaccinated and unvaccinated index cases. The authors rather archly conclude that their findings show ‘that breakthrough infections in fully vaccinated people can efficiently transmit infection in the household setting’. An accompanying editorial is blunter: ‘this study unfortunately also highlights that the vaccine effect on reducing transmission is minimal in the context of delta variant circulation’.

The English study was also plagued with small numbers, and so low statistical power. Nonetheless, unlike most if not all other studies of vaccine effectiveness against transmission (VET), both these studies routinely PCR tested all household close contacts, regardless of symptoms, an essential step if true VET is to be calculated, because it removes potential bias caused by selective testing. This matters — which means it rules out most transmission studies — because without routine testing, most subjects are not followed up: you have no way of knowing whether they were positive, but didn’t get tested, or were real negatives. With that potential bias taken care of, both studies failed to demonstrate any significant difference in covid transmission by vaccinated and unvaccinated individuals in household settings. It is possible there is a small effect that was missed because of the low statistical power of both studies, but any such effect, by definition, is small, and while future larger  studies may demonstrate its statistical significance, they are unlikely to demonstrate any clinical, real world significance. Both studies show that the vaccine effect on reducing transmission is minimal

Those who still cannot see that the Covid Passport Tsar has no clothes might argue that both studies only covered close household contact transmission, and so cannot be extended to cover broader community transmission. But consider this: the covid vaccine passport is intended to reduce transmission in settings that, from an infection risk point of view, are close contact settings: the night club and the football terrace, the church congregation and the crowded assembly. That is their whole point. If the vaccines are unable to reduce transmission in the common close contact setting of the household, it is highly unlikely that they will reduce transmission in other close contact settings. We have no alternative but to conclude covid vaccines have minimal effects on covid onward transmission rates. New strains, including Omicron, are equally likely, if not even more likely, to be unrestrained by vaccination.

The Covid Passport Tsar has no clothes, and, more importantly, he has no evidence. There may or may not be a small effect, but it can only be trivial, the sort of effect that, given sufficient numbers, can be statistically significant, but has no real world significance, or, to stick with the sartorial, it is but a paper jockstrap. In practical terms, in the real world, covid vaccine passports are meaningless, and therefore cannot provide any medical or any public health benefit. Those who fancy covid vaccine passports do have benefit have no doubt trapped themselves in the second half of the quote from Camus, the good conscience delusion; for the rest of us, we would do well to recall the first part of the quote: the well-being of the people in particular has always been the alibi of tyrants. Beware the Covid Passport Tsar, bearing gifts of freedom and movement, for he is really a tyrant in disguise.

Not exactly the most festive of posts. Nonetheless, Dr No begs to take this opportunity to thank all his readers for their continued interest and many welcome contributions, and to wish you all the very best compliments of the season. 


  1. Tom Welsh Reply

    As always, those studies are utterly dependent on the PCR procedure, which is not and cannot be a diagnostic test.

    So as far as I can see all one can hope to accomplish by examining them is to show that “if PCR did work” the vaccines would or would not be effective.

    Since PCR is not a diagnostic test, I cannot help feeling that all of the oceans of print and masses of clever graphs are wasted on a non-problem. Our best way out of the present mess is, as has been pointed out quite often, to turn off the TV and the radio, stop reading newspapers and magazines, and get on with our real lives.

    As far as I can ascertain there is not – and never has been – a pandemic in any meaningful sense of the word, although there may have been one or more minor epidemics of coronavirus.

  2. dr-no Reply

    Tom – agreed, but the point of this post is that, even on their terms ie PCR positivity, the vaccines don’t stop infection or onward transmission, therefore, on their terms, covid passports are meaningless, as they don’t distinguish between those who are infected/likely to infect others and those who aren’t. There are many sound moral reasons not to have covid passports, but the objections raised in this post are research based, and show the passports can not achieve what they are intended to do, which is a strong objection in and of itself, but it also creates another moral objection, introducing a damaging measure which research shows can’t work.

    • Tom Welsh Reply

      Thanks for the clarification, Dr No. I think I understand your position – but it still bothers me that expert and well-informed critics of the government line should accept any of its untrue beliefs, even for the purpose of argument.

      William Briggs points out that “If our level of technology was less, there would have been no bug, there would have been no ability to panic globally, and the technocratic tyranny of lockdowns, vax passports, and vax-mark of the beasts would not have been possible”. https://wmbriggs.com/post/38554/

      Still, I suppose one must use whatever tools are to hand and seem suitable.

  3. Tish Farrell Reply

    Many thanks for this, Dr. No. John Dee has just published his own statistical appraisal of patient records and has come to similar conclusions over efficacy. Need for a big ‘link tidy’ coming up: done! Link is here.

    • John Bowman Reply

      The French Government has tacitly accepted the uselessness of Vaccination Passports by introducing new rules for January, entry to public places only with vaccine passports (now with three doses) AND a negative PCR Test and masks have remained mandatory since March 2020 in public places despite Vaccine Pass.

      Germany tacitly accepted that filthy, dirty, unhygienic, bacteria incubating, snot and phlegm collecting health hazards in general use by the Public are not effective, by mandating surgical type filthy, dirty, unhygienic, bacteria incubating, snot and phlegm collecting health hazards of the respirator masks N95 type because of the fast spreading Omicron. Apparently whilst other masks are effective against all other SARS CoV 2 mutants, they are flummoxed by Omicron.

      The paradox is the more the new rule to stop the spread fails, requiring further new rules, or repeat of previously discontinued failed rules, the more compliant the public becomes.

      What is needed is a vaccine against public gullibility. A boot up the public backside perhaps?

      • Tom Welsh Reply

        John, I fear that creeping government is a self-reinforcing harm. The bigger government gets, the more people (especially the young and naive) expect it to do everything for them. Thus they cease to be able to fend for themselves – and, in this case, especially to think for themselves.

        It is ironic that this trend should have been led by the government of which so much was hoped – that of the USA. A nation founded on a supposed respect for the individual and human rights has gradually but inevitably become a totalitarian dystopia.

  4. Arthur Teacake Reply

    In the UK, the purpose of Covid passports is surely to introduce ID cards. Remember how unpopular they were? Wonder whether the populace has been terrified enough to welcome them this time round?

  5. dearieme Reply

    As a Camus fan I am appalled to learn that he misused “alibi”. It really won’t do.

    Re your supermarket illustration: https://boriquagato.substack.com/p/quarantining-the-vaccinated/comments

    Re vaccine passports: I’ve seen video clips of rude mechanicals singing “You can shove your vaccine passport up your arse”. Vulgar but pertinent.

    Some say it’s all been a vast conspiracy by the Lizard People. I’ve clung instead to the suspicion that it’s been about fear and greed, power and incompetence, and a desire to avoid blame. But the squamate reptiles hypothesis will presumably persist until there’s been a bit of a Reckoning.

  6. dr-no Reply

    dearieme – there has been debate about whether misused ‘alibi’, but on balance, perhaps not. From the OED: “With use as noun compare French alibi fact of having been elsewhere (when a crime was committed) (a1392 in Middle French), bad excuse, pretext (a1467)” – bad excuse/pretext is near enough! Plus the sentence works, both in French and English. We immediately know what he means.

    It is extremely plausible that the covid pass is the alibi of the digital ID tyrant. Just imagine how appealing a digital ID must be to any government! And then along comes covid, and vaccines, and so a need for a portable, real time way to know if an individual has been vaccinated. Job done. Never mind the fact vaccination status tells you nothing about what you really need to know for infection control, what matters is getting those passports cum IDs out there, and accepted as normal by the majority of the population.

    The increasingly irrational behaviours of governments – the ‘doubling down’ to use a dubious modern phrase – are classic examples of escalation of commitment: something clearly isn’t working => obvs, not trying hard enough => double down. There are a number of psychological explanations for this irrational behaviour, and none of them are pretty. Alternatively, it just might all be very rational, on account of all those pounds euros and dollars flowing into certain accounts…

  7. dearieme Reply

    “the ‘doubling down’ to use a dubious modern phrase.” WhenIwasbutalad we said “doubling up” because that was what our fathers said.

    “Doubling down” is an Americanism picked up by the young, who are essentially uneducated barbarians – the sort of people who’d claim the throw a curve ball from left field to let you step up to the plate and go the extra mile to slam dunk the puck in the end zone.

    • Tom Welsh Reply

      dearieme, I share your horror of unpleasant American neologisms – but perhaps “doubling down” has a slightly different meaning from “doubling up”. I think the latter apples to people, for example, who sit two to a seat or whatever. Whereas “doubling down” seems to have a distinctly American sense of “digging even harder when you’re in a hole”.

      • dearieme Reply

        Tom, you must be young. When I was in short trousers the British “doubling up” corresponded almost exactly to the modern American “doubling down”. You doubled up on a bet, for instance.

        I dislike “unpleasant American neologisms” while enjoying the useful – and thereby not unpleasant – ones. Where would we be without now-ancient Americanisms such as commuter, jazz, and whatnot? I enjoy antique American slang.

        The prob is, I think, two-fold. (i) Our young are pig-ignorant and therefore latch onto American uses even when they are unsuitable. (ii) The high standard – I might almost say the spare beauty – of old-fashioned American English is vanishing. Their speech, or at least their writing, is becoming dominated by the verbose, ugly, latinate burbletalk of managerialism, the military, and the “social sciences”.

  8. dearieme Reply

    Good grief, can this be true?

    Robert F. Kennedy, Jr: “… the emergency use authorization vaccines have liability protection under the PREP Act and under the CARES Act.

    So as long as you take an emergency use vaccine, you can’t sue them. Once they get approved, now you can sue them, unless they can get it recommended for children. Because all vaccines that are recommended, officially recommended for children get liability protection, even if an adult gets that vaccine. That’s why they are going after the kids … they need to do it for the liability protection.”


    I don’t mean is his inference true, I mean is his statement of the US law true?

    • Ed P Reply

      The corrupt gangs in America (& the UK etc.) are now engaged in damage limitation, passing the buck and diverting attention to save their rotten arses. They thought they could get away with the biggest medical dystopian plan ever – now it seems there’s a growing interest in exposing them. Let’s hope the cowed & tamed media wake up and start to do their jobs properly again.

      RK Jr. is a hero for our time!

    • Prudence Kitten Reply

      dearieme, Robert F Kennedy Jr is a qualified US lawyer, and has fought many very important cases. So I expect his reading of US law is correct.

  9. tERRY sILK Reply

    I think what is needed is for people to remember that our own immune system if far better than any vaccine assuming that any vaccine has ever been truly effective, but may have been detrimental to peoples health. I hope that their is a re-evalution of the whole disease phenomenon and look with a whole new perspective, I’m not sure whether it will ever happen as long as profits are dependant on the sales of pharmaceuticals though.

    Ed’s Note: apologies for delay in approving, Xmas/New Year etc

  10. dearieme Reply

    Relax, everyone – we’re going to win.

    In the US, President Bonehead and his Dems are facing possible electoral calamity in the autumn of 2022. They will therefore want to boast about their conquest of COVID (it seems they’ll have little else to boast about).

    Consequently numbers will now begin to be spun in the other direction, to suggest that the pandemic is dwindling away and that all will be well for a jolly Spring, Summer and early Fall.

    Politicians in other countries will copy them – no politician will want to be too obviously out of the new “mainstream”. (After all it’s that stupid mindset that got us into this pickle in the first place.)

    Will there ever be a Reckoning for these evil people? You never know but it’s not the way to bet.

  11. dearieme Reply

    But an American seer disagrees:

    ‘It’s obvious that the “Joe Biden” admin wants to run the pandemic for at least one more year, most particularly to keep in place the “emergency” mail-in ballot scam that perverted the 2020 election.’

    Ah well, faites vos jeux!

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