SARS-Cov-2 Vaccine strategy: One Jab or Two?

I’ve been thinking quite a lot about the issue of the Coronavirus vaccination programmes currently underway and have had some interesting and informative exchanges on Twitter about it. This morning’s news that AstraZeneca has finally applied to the European Commission for permission to market its vaccine within the European Union reminded me of those discussions so I thought I’d post a question here. I genuinely don’t know the answer, incidentally, so there’s no agenda here!

As you probably know all SARS-COV-2 vaccines (Moderna, Pfizer/Biontech and AstraZeneca) require two doses, administered about three weeks apart, for maximum efficacy. It’s worth saying before going on that the scientists involved deserve high praise for developing these highly effective vaccines at a speed that has exceeded all expectations.

At the moment however supplies of these vaccines are fairly limited and it’s early days for immunization programmes so there are serious logistical problems to be solved before we get anywhere near full vaccination. I grabbed this from Twitter yesterday showing the state of play in various countries:

Note, incidentally, that Denmark is doing particularly well within the EU but France, Netherlands, Luxembourg and Belgium have started very slowly. Ireland is about mid-table.

At the top of the league is Israel, though  they are not offering vaccination to the Palestinian people whose lands they occupy. Israel has just reported that after 12 days the Pfizer/BioNTech vaccine has about 50% efficacy after one dose based on results from its own programme. That number is roughly consistent with initial estimates of from trials this vaccine but the statistics aren’t great and there is a considerable margin of error on these figures.

Now the question I am asking myself is that given the limited supply is it better at this stage to give as many people as possible one dose of the vaccine, or follow the manufacturers’ original plan and give two doses to half as many people? There are reports that the UK has been deferring the second dose beyond the recommended interval, where there is no data on its efficacy. Perhaps I’m being excessively cynical but it seems to me that the UK Government’s approach is more driven by public relations than by public health considerations.

I understand that there are difficult issues here, not least the ethical one of having people sign up for a specific two-dose vaccination only to find that’s not what they get. Another issue is the speed with which doses are being made available relative to the size of the population. Yet another issue is who you prioritize.

Above all, though, there is the question of what you mean by “better”. One criterion would be to save as many lives as possible. Another might be to slow the rate of infections as much as possible. Another might be to allow the economy to open up as early as possible. These are all different and would lead to different decisions, particularly with regard to who should get the vaccine. Saving lives obviously means protecting the vulnerable and the people who care for them (e.g. health workers). Economic considerations would however lead you to prioritize those on whom the economy depends most directly, which would include workers who can’t easily work from home (many of whom are in low-paid manual jobs).

The following poll is therefore going to be very unscientific, but I’m interested to find out what people think. In  order to keep it simple, lets suppose you have a batch of two million doses of a vaccine (say the Pfizer one) and the next batch is due in three months.

You have to decide between the following two options:

  1.  Give 1,000,000 people one dose now and another dose in three weeks’ time
  2.  Give 2,000,000 people one dose now and hope that it is effective for three months (or that additional supplies appear more quickly than anticipated).

Vote now!

A similar poll I did on Twitter a while ago can be found here: there are some quite interesting comments in the ensuing thread.

Comments are of course welcome through the Comments Box!

P.S. I’m quite low down the pecking order in Ireland so it’s unlikely I’ll get vaccinated before the summer.

17 Responses to “SARS-Cov-2 Vaccine strategy: One Jab or Two?”

  1. Nigel Foot Says:

    I’d go for option 1. If the manufacturer’s data is followed, the two dose regime gives over 90% effectiveness. My fear is by giving one dose (perhaps 50-60% effectiveness) we may allow scope for vaccine resistant variants to appear.

  2. There is an additional problem (that’s quite hard to quanitfy) from giving people one dose and then waiting longer than recommended: with high levels of virus circulation in the population, we may drive the virus to evolve in a way that’s vaccine resistant. The current variants all still seem to be susceptible to the vaccine, but this may not remain true.

    However, to stop that, we need to get circulating virus down, and give as many people as possible two doses of vaccine within 3 weeks. And that seems to be beyond the UK government.

  3. According to the Finnish Institute for Health and Welfare (THL), vaccination in Finland is more like 0.9% today but there’s a data bottleneck in reporting from smaller towns. THL also said this week that half of doses will be held back for 2nd shots and half will not on the basis of slower-than-expected but consistent deliveries from Pfizer.

    But we’re not in the kind of crisis the UK or France is.

  4. Jonivar Skullerud Says:

    That table is odd. It does not include UAE and Bahrain, which are currently second and third for vaccinations per head of population with 12.9% and 5.8% respectively. Both are using the Sinopharm vaccine i believe (not sure if it is the Wuhan or Beijing version) although Dubai is also using Pfizer-BioNTech.

    • telescoper Says:

      It is. The dates are all different too. The table was tweeted by Fergal Bowers but he didn’t say where he got it from nor why he hasn’t figured out how to use the print screen facility properly.

  5. Anton Garrett Says:

    I don’t think it matters very much. I applaud the vaccine science but I think the failure of governments to take Vitamin D seriously in relation to covid19 is depressing. This video interviews three retired mainstream medical researchers into Vitamin who have kept abreast of the pandemic:

    The comments about the higher death rate among UK doctors who are BAME than white doctors show that this correlation has little to do with poverty, since doctors are paid well. (Vitamin D is synthesised by the action of sunlight on human skin; this fact was arguably the driver of the evolution of lighter skin far from the equator.) One speaker says that after a swift top-up of Vitamin D the BAME doctors in one part of the UK stopped getting ill and dying of covid19. Also, the high covid19 death rate in Northern Italy and the low death rate in Japan are strongly (negatively) correlated with Vitamin D levels in those places. Covid19 has so far had two peaks in the northern hemisphere, both at times of year when its synthesis in skin acted on by sunlight is largely absent.

    One of these medics says that the vaccines will work fine against SARS-CoV-2 but in a minority of cases will cause a bad reaction unless you are topped up with Vitamin D when you get jabbed. I look forward to the vaccine both personally and for society but am ingesting plenty of Vitamin D. The recommended daily dose is considerably less than what I’d get from half an hour stripped to the waist in the summer sun. Cod liver oil is hardly a fashionable cocktail component, but I don’t regret it.

    • For various reasons, I have been taking vitamin D in the winter for several years, but not in the summer, since all skin is exposed to sunlight most of the time. As part of other regular tests, the level in the blood is checked, so that the dosage can be adjusted if necessary.

      One can overdose on it. In fact, pure vitamin D is very toxic. In many countries, one has to have special permission to buy it. Vitamins B and C (in contrast to A, D, and E) are water-soluble hence it is almost impossible to overdose on them. While one should have enough, despite Linus Pauling there is no good evidence that substantially more than the recommended dose does one any good.

    • telescoper Says:

      There’s a discussion of this in a recent issue of The Lancet. In general they consider the case for its effectiveness against Covid-19 to be unproven.

      As it happens, I’ve been taking Vitamin D supplements to help with my arthritis anyway. I would argue that, even if there isn’t strong statistical evidence in favour of its use against Covid-19, since it is (a) readily available and (b) is not harmful in proper doses, there’s really nothing to lose by trying it.

      I take tablets, by the way, not Cod Liver Oil although I remember being given that when I was a kid.

      • Anton Garrett Says:

        I don’t know if you and Phillip have seen the video (it’s an hour long, unfortunately) but it’s worth viewing, as my own summary cannot begin to be ample. I’d back the expertise of these guys and from memory I think they even mention the Lancet article critically.

        I take tablets *and* cod liver oil, because the tablets contain other supplements that you can definitely overdose on. I don’t understand Phillip’s comment that you can OD on VitD in view of how much of it would be synthesised by sunbathers.

        They say it takes time to build up VitD levels unless you take a particular fast-acting form which oddly can be had over the counter in Italy but not here. They don’t mention – clearly because they weren’t asked – how quickly what daily dosage reaches the bodily concentrations they recommend. What they do say, amusingly, is that adequate VitD levels will protect you if you are one of the potentially unlucky ones who react against the vaccine, but if you have those VitD levels then you will be protected from covid19 anyway, experience SARS-CoV-2 as no worse than a cold.

        I repeat that I look forward to the jab but the neglect by government of these claims is distressing. How many people are dying or suffering needlessly?

      • telescoper Says:

        The video is dated 28th December; the Lancet article I linked to is just 11th January so they won’t have referred specifically to that.

        I will watch it but haven’t yet as I’m already multitasking!

      • I don’t understand Phillip’s comment that you can OD on VitD in view of how much of it would be synthesised by sunbathers.

        From Wikipedia:

        Excessive exposure to sunlight poses no risk in vitamin D toxicity through overproduction of vitamin D precursor, cholecalciferol, regulating vitamin D production. During ultraviolet exposure, the concentration of vitamin D precursors produced in the skin reaches an equilibrium, and any further vitamin D that is produced is degraded.

        https://en.wikipedia.org/wiki/Vitamin_D_toxicity

      • Anton Garrett Says:

        Thanks Peter; Phillip – if excess vitD is degraded then why is excess by mouth poisonous as you say? Is there some biology I am missing here?

      • There is some more about it in the Wikipedia article.

        If it weren‘t dangerous, there would be no restrictions on buying large quantities in pure form.

      • Not only is there nothing to lose, the NHS already actually recommends everyone should be taking it during winter because you cannot get enough through sunlight.It seems not many people are aware of this and hence not many people take it (I only know a few). If it helps covid that would be a bonus of course 🙂

    • telescoper Says:

      This issue has come up in the latest letter from the CMO in Ireland who concludes that the evidence is only circumstantial:

      Click to access 184e8d00-9080-44aa-af74-dbb13b0dcd34.pdf

  6. Dave Carter Says:

    I would do what the vaccine manufacturers have tested and say produces the strongest immunity. They may not be as far away from this with the Oxford Jab, but BioNTech are clear that they havn’t tested the long time gap that the UK government is proposing.

  7. i agree with some above that taking only the first dose will give the virus a chance to mutate and come back stronger. As a nurse i have just been offered my vaccine and am scheduled for this friday. However, i have been developing some congestion and am a bit run down from lack of sleep so am wavering about getting it right now.. Most nurses i have talked to state that even though they were healthy when they took it, it knocked them down for several days, and that the second dose was even worse. I certainly cannot afford a week or two off work with no compensation. So, i may cancel due to not feeling up to par. But just like with antibiotics, i would never do half measures and risk a more resiliant strain taking hold.

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