COVID vacccines are you ready for another go?


As you are aware the UK was the first place to approve COVID-19-related vaccinations in late 2020. Vaccines were made so fast because the virus was identified and the sequence was given to the World. This is known to some a Wuhan strain or the A strain or the Index Virus. The first major variant to surface in the UK was called the UK/Kent strain but was given an offical number B.1.1.7. It was given the name alpha, Whilst other variants were circulating in South Africa (Beta) and South American (Gamma). The SARS-CoV-2 vaccines were based on the Index strain sequence and this produced antibody lasting about 6 months in terms of protecting against infection and probably life-log immunity. To stop infection you need a certain level of antibodies that can swamp the virus as it infects and so prevents clinical disease.

The protective levels remained high for a few months but because we were isolating/shielding we were not encountering any natural virus, so immune system thinks job done, shut down production. So with time your protective immunity disappeared and so you could get infected before you can make new and enough antibody to deal with infection.

The next strain to hit the UK was delta. Whilst it was more infective than the original strain, the vaccine response was pretty effective, but you needed a slightly higher level of antibody to protect against it. Hurray and most of the UK was vaccinated and booster and infection rates and deaths dropped in the vaccinated majority.

So as we were patting ourselves on the back, the virus had other plans and it mutated to develop immune-escape meaning that you need alot more antibody to stop it infecting. We had seent this with beta and gamma…but omicron took this to a whole new level. This had loads and loads of mutations compared to what had gone before….mutation in an immunosuppressed individual that couldn’t clear the virus or maybe a species evolved in animals that jumped back to humans.

Amino acid sequence of the SARS-COV-2 viral variants int the Spike, There was one difference in the receptor binding region or alpha compared to Wuhan (the orche Y) in Omicron DA4. BA.5 tere are 17 difference starting with Blue D at position G339 to Green H at position Y505 (source WHO)

Now it meant we didn’t need a doubling of antibody levels to stop infection we needed 10 or 20 or hundred times the wuhan-directed antibody level to give infection. Because the antibodies were waning with time the level required to stop infection soon was lost and so the protective effect of vaccination lasted a few weeks as a consquence most people vaccinated with Wuhan developed COVID-19 in 2022 due to infection with omicron. As BA.4. and BA.5 became dominant the vaccine was alot let efficacious

So now we have a new vaccine, which will boost the response to the Wuhan strain but will give protection against omicron. Therefore it should mean that the level of antibody required to stop infection will be lower as we will now make antibodies specific for omicron. This is why it is a good idea to get a boost with the new omicron COVID-19 vaccine.

In addition, things have changed and we are now “out and about” and this means we will encounter omicron or whatever comes next. This means we will get sub-clinical infections because we are getting infected whilst we still have a vaccine response, this gets rid of the infection but gives you a boost. so your antibody levels will increase again. If this happens repeatedly you can develop high levels of protective antibodies that give you long-term protection

Sadly for MS, people taking fingolimod, ocrelizumab and rituximab did not make a good antibody response increasing infection risks. This was partially countered by booster doses that increased the antibody response in people making a response and increased the proportion of people making a response. For anti-CD20 the capacity to respond related to the therapeutic antibody levels and the B cell counts, which have a relationship between CD20-depletion and vaccination.

The antibody responses were increased in fingolimod and anti-CD20 took a break, but given that disease can return many consider this an unacceptable risk, but in rheumatoid arthritis and cancer they have formally tested the “treatment breaks” with immunosuppressive drugs and it can work. Likewise increasing the number of boosters help some individuals make a response.

I will be waiting to get my boost, don’t forget to do your bit for Society…it is not about you! It is about protecting the populaton. The newly approved vaccine will target BA.1 omicron, another version targeting BA.4/BA.5 is a month or more behind the one approved today. Will the UK get to approve this first too.

COI: None

Disclaimer. These are my views and my diagrams created with Biorender.

About the author



  • This is really useful. I can now point out that if I never leave the house again, my immune system will simply stop working, thinking there’s no danger. My wellbeing depends on social interaction, but certain family members are implying that their death “will be on my conscience” if I bring back Covid. Please!!!

  • I am on ocrevus and eligible for a booster as of 7/1. I had my last booster on 3/1 and I had covid at the end of April. Should I get current vax or wait until new one comes out, with it potentially being more effective? I am scheduled for next infusion the first week of October . In the US so my physician is saying Fall in terms on new vax being available. Leaving it up to me as to get now or wait.

  • Thanks for all your updates on this Mouse Dr. Is there a chance those of us with MS may soon be offered the Evushield infusion rather than vaccines going forward or is this still unlikely in the UK?

  • Sorry just wrote that “test” comment because I can’t seem to dismiss the cookies notification, and I think it prevented me from commenting this morning.

    This new vaccine is good news though I’m not sure I’d be wise to have it. My first Moderna experience was a bit more “near death” than expected. I’m so keen to protect myself against the virus and all of its variants, but fainting, two weeks off work with concussion, a scar on my face, and two months off running or cycling waiting for a cardiology referral then results was too high a price for me to pay. I’m guessing the new vaccine is similar to the one I had, just tweaked.

    I was fine with 3x Pfizer though – do you know if they are updating their vaccine?

  • How is this vaccine doing your part for others/society when it does not stop transmission??

    If you want to do it for yourself, fine, but current knowledge is well past the point of believing it stops the spread.

    And that’s not even getting into the lack of lengthy trial data.

  • How is this vaccine doing your part for others/society when it does not stop transmission??

    If you want to do it for yourself, fine, but current knowledge is well past the point of believing it stops the spread.

    And that’s not even getting into the lack of lengthy trial data.

    • it will limit how long you shed virus thus limiting you caoacity to infect others and this new vaccine may be much better in stopping you getting infected meaning less people you may pass this to

    • Don’t know where you’re coming from TG, but I hope it’s not this: With MS, we live in a world of uncertainties. It is not black and white, either-or. Most of us know that and wish it were another way. Covid now adds to it, (depending). Logic only points to lesser infection and therefore decreased transmission with a vaccine. Do this with most people and you’ll have made a difference to those who prefer not to be seriously ill.

      Two groups- one vaxxed. Another yes and no. Which one should I hang with to lower my chances of infection? And what should I do to lower my chances of serious infection, especially if I’ve got other stuff going on and I really don’t want to get seriously ill? Should I have a mask at the ready? What will people think of me if I put on a mask? (I say this from “ground zero” of the deniers here in The US).

      So here in The US, it seems there is plenty of social movement not to alter “survival of the fittest”, because if altered, the rights of others will be trampled somehow by those who survive and otherwise would not have. Some of us don’t have the ___ to worry about others, unless they too are people inclined not to worry about others. Then we stick together 🙂 Now, here, some say vaccination never worked. What a movement. [venting over]

      Nice summary MD.

  • I had three Pfizer rounds and no antibodies whatsoever (ocrelizumab) so got evusheld a few months ago.

    Thinking to get another evusheld round when available.

    Out of interest, what would happen if I got another round of mrna vaccine now, would the evusheld bind to the spike protein and be used up?

By MouseDoctor



Recent Posts

Recent Comments