先打也不一定先贏。

In rare cases can the Pfizer/BioNTech and AstraZeneca/Oxford vaccine be mixed and matched?

We do not recommend mixing the COVID-19 vaccines – if your first dose is the Pfizer vaccine you should not be given the AstraZeneca vaccine for your second dose and vice versa.
However, there may be extremely rare occasions where the same vaccine is not available, or where it is not known what vaccine the patient received.
Our guidance is very clear that every effort should be made in these instances to give the same vaccine to the patient, but where this is not possible it is better to give a second dose of another vaccine than not at all.
This is a reasonable measure on a very exceptional basis, when the alternative is to leave someone with an incomplete course – which is the greater concern, especially if the individual is likely to be at immediate high risk or is considered unlikely to attend again.
In these rare circumstances, as both vaccines are based on the spike protein, it is likely the second dose will help to boost the response to the first dose.
While there is no evidence on the interchangeability of the COVID-19 vaccines at this time, this is a pragmatic and scientific approach agreed by many scientists and vaccine experts, including the UK’s Deputy Chief Medical Officer.

https://britishlivertrust.org.uk/up...vid-19-vaccine/


在極少數情況下，輝瑞/BioNTech 和阿斯利康/牛津疫苗可以混合搭配嗎？

我們不建議混合使用 COVID-19 疫苗——如果您的第一劑是輝瑞疫苗，則您不應在第二劑接種阿斯利康疫苗，反之亦然。
但是，在極少數情況下可能無法使用相同的疫苗，或者不知道患者接種的是哪種疫苗。
我們的指導非常明確，在這些情況下，應盡一切努力為患者接種相同的疫苗，但在不可能的情況下，接種第二劑另一種疫苗總比不接種要好。
在非常特殊的情況下，這是一種合理的措施，當替代方案是讓某人完成不完整的課程時——這是更大的擔憂，尤其是如果該人可能面臨直接的高風險或被認為不太可能再次參加。
在這些罕見的情況下，由於兩種疫苗都基於刺突蛋白，因此第二劑很可能有助於增強對第一劑的反應。
雖然目前沒有證據表明 COVID-19 疫苗的可互換性，但這是包括英國副首席醫療官在內的許多科學家和疫苗專家都同意的務實和科學方法。


台灣指揮中心目前是這樣但是....指揮中心常常在改....