Is there and could there be any benefit to delaying the second dose of the mRNA Pfizer covid-19 vaccine when it comes to reducing the risk of myocarditis associated with the vaccine?
I'm quite sure that there's no definite answer to this question at the moment, but I'd like to hear an informed guess. According to vaxopedia.org,
Most of the (myocarditis) reports are after the second dose, and interestingly, there are no increased reports of myocarditis in the UK, where they routinely delay the second dose so as to prioritize as many people as possible getting a first dose.
Additionally, sciencemag.org writes:
One important question is whether delaying the second vaccine dose might reduce any potential risk. There may be an opportunity to find out: Several countries have stretched the interval between the two doses from the 3 weeks tested and recommended by Pfizer to 12 or even 16 weeks, because they want to give as many people as possible at least one shot. A drop in myocarditis cases among those whose second dose was delayed might show up in data in the months ahead.
Is there any publicly available data that might offer a clue?
On the other hand, it seems that delaying a COVID vaccine’s second dose boosts immune response so perhaps it could increase the probability of getting myocarditis? If so, what could be the mechanism in that case?
A quick note to preempt some potential comments: it is quite clear that delaying the second dose increases one's risk of covid-19 and hospitalization, especially due to the Delta variant running rampant; however, this question addresses only the risk of myocarditis.