Vaccine question!

I am

Pregnant with my 4th child and I was just informed that if my now 16 month old son get vaccinated with a live virus vaccine, my baby that I'm pregnant with could catch something and die? I've literally never heard this and I vaccinated all

Of my kids while I was pregnant.. I don't understand how now this is a thing?

Should I not

Get his live vaccines? He's delayed already.. he needs his shots...