1月31日，美国政府宣布新型肺炎疫情为公共卫生紧急事件，自美东时间2020年2月2日下午5时起，过去14天内到访过中国大陆（不含港澳台）的旅客，将不得入境美国。以下情形除外：
- 美国公民和美国永久居民（绿卡）。
- 公民或绿卡的配偶。
- 未满21岁未婚公民／绿卡的父母／监护人。
- 公民／绿卡的兄弟姐妹，若双方都未满21岁且未婚（即美国移民法中的「儿童」）。
- 公民／绿卡的子女，以及持 IR-4、IH-4 签证的待收养子女。
- 受美国政府邀请前来遏制新型冠状病毒的人。
- 航空／航海机组人员。
- 外交人员及直系亲属。
- 根据 CDC 或其指定人员的决定，其入境不会对引入、传播或传播该病毒，造成重大风险的外国人。
- 根据总检察长或其指定人员的推荐、经国务卿、国土安全部长或其指定人员决定，入境美国执法的外国人。
- 国务卿、国土安全部长或其指定人员决定的符合国家利益的外国人。
上述不受禁令限制的人士，包括美国公民和绿卡，若在过去14天内到过中国湖北省，入境后将接受14天强制隔离。若没到过湖北，但到过中国的其他省份和地区，入境时将接受健康筛查，并在家隔离14天。
对于不符合上述例外情形的人士，如留学生、B1/B2 签证，仍需来美国的话，最靠谱的方法可能是去目前没有此类限制的第三国（或香港、台湾、澳门地区）停留至少14天，再转机来美国。该禁令并非针对中国公民，其他国家公民，只要近期到过中国，14天内同样不许入境。至于为何是「14天」，因为该病毒的潜伏期大致为14天，若你离开中国大陆后14天没有症状，则视为安全、无健康风险，所以允许正常入境美国。
该禁令没有明确的时间限制。每15天卫生部长会向总统汇报并建议是否应延长、修改、或中止此禁令。只要总统未签字中止，该禁令将一直持续。
上述例外情形的原文如下：
Sec. 2. Scope of Suspension and Limitation on Entry.
(a) Section 1 of this proclamation shall not apply to:
(i) any lawful permanent resident of the United States;
(ii) any alien who is the spouse of a U.S. citizen or lawful permanent resident;
(iii) any alien who is the parent or legal guardian of a U.S. citizen or lawful permanent resident, provided that the U.S. citizen or lawful permanent resident is unmarried and under the age of 21;
(iv) any alien who is the sibling of a U.S. citizen or lawful permanent resident, provided that both are unmarried and under the age of 21;
(v) any alien who is the child, foster child, or ward of a U.S. citizen or lawful permanent resident, or who is a prospective adoptee seeking to enter the United States pursuant to the IR-4 or IH-4 visa classifications;
(vi) any alien traveling at the invitation of the United States Government for a purpose related to containment or mitigation of the virus;
(vii) any alien traveling as a nonimmigrant under section 101(a)(15)(C) or (D) of the INA, 8 U.S.C. 1101(a)(15)(C) or (D), as a crewmember or any alien otherwise traveling to the United States as air or sea crew;
(viii) any alien seeking entry into or transiting the United States pursuant to an A-1, A-2, C-2, C-3 (as a foreign government official or immediate family member of an official), G-1, G-2, G-3, G-4, NATO-1 through NATO-4, or NATO-6 visa;
(ix) any alien whose entry would not pose a significant risk of introducing, transmitting, or spreading the virus, as determined by the CDC Director, or his designee;
(x) any alien whose entry would further important United States law enforcement objectives, as determined by the Secretary of State, the Secretary of Homeland Security, or their respective designees based on a recommendation of the Attorney General or his designee; or
(xi) any alien whose entry would be in the national interest, as determined by the Secretary of State, the Secretary of Homeland Security, or their designees.