Covid-19 - Spain - A completely unvaccinated person, wants to get the covid-certificate / covid-passport, what's the logic of requiring all 3 jabs, instead of just the latest 1 or 2 jabs ?

  • Is the original strain of covid that swept europe / america in early 2020, still floating around, is this the logic of requiring the first jab for a completely unvaccinated person, to be the original first jab ?

  • Why can't the 'jab' requirements for the first 'jab' for a completely unvaccinated person be quickly revised, especially in the light of the arrival of something like Omicron ?

  • Just how unwise would it be to now abandon the first 1 or 2 'jabs' given here in Spain ?

1 Answer 1


Your question is founded on a misconception. The material in the syringe is the same for all 3. It has not been adjusted for new strains. (See for example this government of Canada info page on the Pfizer vaccines.) It doesn't need to be: it protects against the new strains as well as the old. In some cases the degree of protection is slightly less, eg 92% instead of 95% kind of thing. The vaccine is the vaccine and that's that.

Like many other vaccinations, full immunity requires more than one dose. (See this example for hepatitis.) You can't get "just the third jab." Whatever you get now will be your first. You will have some protection, and several weeks later you can have a second and get more.

The exact spacing between vaccinations varies with factors like "how much vaccine do we have?" - some countries delayed second shots to get more people first shots, then it turned out those people had more immunity so the recommendations changed to a longer spacing. But now we're facing things like "against Omicron it's better to have a second that gives you x% (even though you'd get x+something% if you waited) than just a first that gives you a much smaller y% protection."

Anyway, go get one shot. It will give you some protection. Then, after the spacing recommended where you live - probably 3 to 8 weeks - get a second. Then don't worry about the third for 6 months after that.

  • Beat me to it by a few seconds. I would add something about the vaccine still protecting against these new strains too.
    – bob1
    Dec 5, 2021 at 20:15
  • @bob1 good idea, done Dec 5, 2021 at 20:22

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