Hey mama! I haven't personally gone through pregnancy boosters yet, pero a few of my mum friends did get boosters during their second and third trimester kasi ang OB nila recommended it, yung isa namin nag-Pfizer booster around 7 months and she was fine, no issues. Best to ask your OB directly though kasi may mga factors na specific sa bawat pregnancy, like kung anong vaccines available sa clinic ninyo or your health history, they'll guide you kung safe talaga for your situation. Let me know what your doctor says, curious din ako!