Just keep in mind, Vietnam has a VERY low instance of Coronavirus.
Very low.
Vietnam may have a low incidence of Coronavirus. But when it’s publicized that a US aircraft carrier is going to be docking in Vietnam, it’s not a stretch to suspect an enemy would intentionally send a human carrier to infect persons from that US aircraft carrier. And then there is the by chance infection that could have come from a sweet spouse who made his/her way over to Vietnam to spend some special time with a spouse on liberty. Even submarine officer wives do this.