連結：https://www.nytimes.com/2021/12/23/health/booster-protection-omicron.html
兩針AZ後打BNT或莫德納
Among people who received two doses of the AstraZeneca vaccine, a booster
with one of the mRNA vaccines, made by Pfizer and Moderna, was 60 percent
effective at preventing symptomatic disease two to four weeks after the shot.
After 10 weeks, however, the Pfizer booster was just 35 percent effective.
The Moderna booster was 45 percent effective at up to nine weeks.
2-4週 有症狀保護力60%
10週以上 BNT 35% 莫德納45%
For people who were given three Pfizer doses, vaccine effectiveness dropped
from 70 percent one week after the booster to 45 percent after 10 weeks.
Pfizer recipients who received a Moderna booster, on the other hand, seemed
to fare better; their vaccine regimen remained up to 75 percent effective at
up to nine weeks.
BNT三針 一週後保護力70% 十週後45%
莫德納 九週後75%
但英國打BNT應該還是多很多，可能有總數上的差異
簡而言之，打第三針還是不能防感染