NEW YORK (CBS/AP) — U.S. health officials on Monday recommended little more than voluntary, at-home quarantine for travelers from West Africa who are at highest risk for coming down with Ebola, and symptom monitoring for those at lower risk.

The Centers for Disease Control and Prevention issued the updated guidance on Monday.

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The CDC guidance comes after the governors of New York, New Jersey, Illinois and Maryland announced mandatory quarantines for medical workers returning from three West African countries plagued by the worst Ebola outbreak in world history.

Meanwhile, Gov. Christie defended the temporary state-ordered quarantine of a nurse from Maine who returned home from helping patients in West Africa. She was released from quarantine in New Jersey on Monday and was to complete her 21-day quarantine in her home state.

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“If you are screened and you are asymptomatic, you can be allowed then to go to your home, travel to your home, whether it’s in New Jersey, New York or someplace else in the country and be quarantined for 21 days there. If you are symptomatic, you will be quarantined in a hospital in New Jersey until we can find out whether you have the virus or not,” Gov. Christie said.

“That’s the policy Governor Cuomo and I laid out on Friday. It’s the policy that has been instituted since that time that dealt with the woman from Maine and will deal with anybody else who is a healthcare worker who has direct contact with someone who has the Ebola virus. There has been no change. No difference. That’s the policy and that’s the way it continues to be,” Christie continued. “And by the way, the state of Florida, the state of Illinois, the state of Maryland, the state of Virginia, all since we’ve shown leadership, have now adopted that plan.”

Christie also said that he and Gov. Cuomo were “both unsatisfied with what the CDC was doing” previously.

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But experts say the state actions are unnecessarily severe and will discourage health workers from going to West Africa to fight the epidemic. The CDC said travel restrictions could be ordered in certain cases, but voluntary quarantine is enough for those at highest risk.

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