Covid-19: So Why Do We need a Booster?

See caveat-emptor regarding my status in bio-medical sciences at end.

It looks like the anti-vax scare-mongers on Twitter are having a field day over the UK’s roll out of a so-called “booster” or third vaccine dose. But some of the questions being asked are coming from fair-minded people too. They need addressing.

  • How many boosters will we need? 
  • Why do we need a booster at all? 

To be fair these are reasonable questions. 

Unfortunately the  poisonous superstition, vitriol and scientifically-vacuous sneering from the anti-vax lobby mean they tend to get ignored. Or regarded as irrelevances. Which they most certainly are not

But now even hard core EU Remainers are piling in! 

The third dose is usually (but not always) the Pfizer Vaccine. Whereas in the majority of UK cases, the first two were Astra Zeneca. 

So now the AZ vaccine (an innocent bystander in all this) has become a target for derision and vilification among Remainers . In some cases they are (quite shockingly) suggesting it doesn’t work at all!

But none of this fear-mongering and character assassination addresses the issue. 

Understandably, reasonable people feel a uncertain as to why we need a third dose. After-all nobody mentioned it during the initial vaccine roll-out! So why is it so important now? 

Below is (imho) the fundamental question. And hopefully a sensible answer as well.

So why exactly DO we need a booster? 

Frankly the government has been very poor in explaining this. That's if they’ve done any explaining at all.

But there are very good reasons for a booster and also for the booster regime. 

These reasons, if explained properly would, I am sure, significantly help people come to a logical conclusion that getting a booster is the right course of action.

I thought I’d do a little research and give my (amateur) opinion. I hope it helps.

So here is. I’ll try and dispel some misconceptions as I go along:

Vaccine efficacy does not last forever. Neither do vaccines offer a cast iron guarantee of 100% immunity, even from day one. This is just as true for Covid-19 vaccines (all varieties) as for other vaccines. 

Yet these Covid-19 vaccines do offer high initial protection against the disease and a strong residual protection too.

Here’s some figures. (from BMJ and Nature)

Two doses of Pfizer give (initially)  up to 95% immunity. This then tapers off to 62% after 20 weeks.

Astra Zeneca figures are a little more difficult. As it was first of breed vaccine there was a variation in the dosage regime as it evolved. But  at best (latest regime) it offers an initial 90% immunity or at worst (original regime) 70% immunity.  The BMJ (here) reckon that there is now less than 1% between protection level offered by Pfizer and AZ. 

The down side with AZ is that this protection tapers off to around 45% after 20 weeks.

So it looks like the efficacy of AZ decays more rapidly than that of Pfizer. Or the Moderna vaccine which apparently behaves similar to Pfizer and is usually used as the booster for Pfizer. But they all decay.

The result of this waning immunity is a rising number of double jabbed people in hospital. But the number is still a tiny fraction of what would have been the case without vaccination (or a delayed vaccine roll-out)

Where AZ wins out over Pfizer is logistics. 

AZ does not need a specialist cold cabinet. It will evidently still remain active even if left on the bench for 6 hours. Not so Pfizer. 

So rolling out AZ is (and was) much, much easier ( and hence rapid) than rolling out Pfizer.

 Brexit/Remain (or whatever) had absolutely no impact on this simple logistical fact.

No doubt any hard-core anti-vaxxers still reading this will now be eagerly ramping up some dogma-based misconception that this immunity decay mean that “vaccines don’t work”. 

But they’d be wrong.

First of all, there are the lives already saved (many, many thousands)

Secondly a booster - especially a booster from a different vaccine type will push that immunity back up beyond 90%. Hence the "booster" program.

The reason why AZ is not being used for the booster is that while a third doze AZ would still actually significantly increase immunity back up to a high level, a mixed vaccine regime has been found to increase immunity even more. (here)

So one simple booster will in essence give very good (90+%) immunity for another 6 months or so. Or into the Summer. Where things then get easier. (viruses hate heat and sun).

We may have to live with Covid-19 boosters for a number of years or maybe even indefinitely. Much as we do with Flu and pneumonia vaccines. 

But that is the way it is. 

We can accept it and do the right thing (i.e.get a booster) or we can bottle out which panders to dogma and superstition. 

Or if we are some sort of bitter Remainer we can try and make political capital out of a small crease in arguably the most successful large vaccine roll-out ever seen in the UK and possibly the world.

I fully appreciate that some of the current restrictions on work, movement, gatherings, face coverings, etc. are at times nonsensical and sometime descend to the level of high farce. But however stupid they may be at times, they DO NOT and should not affect peoples continued willingness to combat this disease with a vaccine booster.

I’m all jabbed up. I hope you are too. If though you are not, please remember what happened in 1918. (Spanish Flu). Back then they did not have the luxury of a vaccine.   

I know (from bitter experience) the on-line booking system is chaotic. But persevere. You (and the rest of us) will get there in the end. 

Caveat: I am NOT a biomedical scientist. This is my opinion as a Retired System Engineer. It is though based on what I regard as highly reliable references. But personally, I wouldn’t know the difference between an BNT162b2 vaccine an mRNA-1273 vaccine or a ChAdOx1 vaccine if it bit me on the arse.