Nazrief said he has no idea how baby Noah was infected.
"We have never brought Noah on outings, except around the house. He has not seen anyone except for hospital staff during check up," the 29-year-old actor told mStar, The Star's Malay-language portal.
"I am not pointing fingers at anyone but my newborn didn't meet anyone else. I am perplexed as we have only been to the hospital."
Both Nazrief and his wife, who have been vaccinated, tested negative.
He also gave an update on Noah's condition to mStar: "He is fine. He doesn't have major symptoms ... just a little phlegm."
The actor went on to advise parents to be more aware especially at a place that is of high risk.
"When you bring your child for check up, don't let others or nurses hold your child. Because we don't know if they have been in close contact with others prior to meeting us, so it is best you handle your own child. If you're weighing the baby, hold the child yourself," he said.
Nazrief, his wife and Noah are in self-quarantine until Sept 30.