BMJ is one of the top medical journals. Not quite Lancet or NE JM, but widely respected.I don't know BMJ but maybe dj can jump in:
Covid-19 vaccination: What’s the evidence for extending the dosing interval?
On 30 December the four UK chief medical officers announced that the second doses of the covid vaccines should be given towards the end of 12 weeks rather than in the previously recommended 3-4 weeks. Gareth Iacobucci and Elisabeth Mahase look at the questions this has raised In a letter sent...www.bmj.com
There is just not enough evidence for how delaying the mRNA vaccines effect antibody responses. 3-4 weeks was chosen based on past studies because it worked best for the booster. Why even do phase III trials at all if you are just going to change things on the fly?
I have fewer questions on waiting 12 weeks for the live vaccines like AZ. That was actually beneficial in the data we have. The mRNA vaccines are inherently less immunogenic because they are not alive. You may be losing some memory cells during those extra weeks, which may lead to less antibody. The truth is nobody knows for sure. When my partner got the Pfizer vaccine, the second appt was scheduled at the same time. It is hard enough getting people back in a timely manner without muddying the water about when people should get it again.