does the second dose of vaccine need to be the same brand as the first?

so far yes, that's the rule around the world. In thailand there is now not a choice for sinovac.

And knowing thai mentality they would not step up against when AZ become available later on.

But gradually would be relaxed, when there is surplus.

Makers if vax started cooperate already in mixing their doses.

Since december there is research into mixing AZ with sounik.

Chinese are talking about moxing 5 vax which they already have, but non of them of great potency.

More recently AZ is experimenting with mixing Pfizer, Moderna and Novavax

https://www.ox.ac.uk/news/2021-02-04-oxford-leads-first-trial-investigating-dosing-alternating-vaccines

 

personally I would rather wait a little for the second dose to be different. Or take it as a third dose

 

It depends on the type of vaccine you got. If your first shot was one of the mRNA type of vaccine (Moderna,Pfizer) you should continue if one of the two, while if you had Astra Zeneca you could have the second shot with Johnson or any other vaccine develeped with the same technology (deactivated virus).

The UK guidelines do permit mixing the vaccines but only under specific circumstances which were expected to be quite rare.  I understand confidence is high that it would be successful, but trials to prove it haven't been completed.  Same was said about the longer time between doses the UK permits and it has been a roaring success.

In the US it's the same, you need to take the same vaccine you got for the first shot, for the second.

 

Now both me, my wife, all the kids plus my ex wife got the pfizer shot, and half of us had the dreaded reaction to the second dose, flu like symptoms and for me at least intense tiredness. I'm a guy that generally sleeps four hours a night.

That day I slept for a solid 12 hours!

 

An interesting article from AARP on why that is actually a good thing, and why if you get a mRNA vaccine that second one of the same type is important

 

https://www.aarp.org/health/conditions-treatments/info-2021/second-dose-vaccine-side-effects.html?cmp=SNP-BRD-FB-COVID-2021AABGRANT

20 hours ago, GinBoy2 said:

An interesting article from AARP on why that is actually a good thing, and why if you get a mRNA vaccine that second one of the same type is important

 

I can see the first point from the article, but don't see any comment on the second.  Have I missed something?