Center for Research in Policies, Population and Health, Faculty of MedicineUniversidad Nacional Autónoma de México (UNAM), Edificio CIPPS, Piso 2, Cto, Centro Cultural Universitario S/N, C.U. Coyoacán, 04510, Ciudad de México, Mexico.
Traveler's Preventive Care Clinic, Facultad de MedicinaUNAM, Aeropuerto Internacional de la Ciudad de México "Benito Juarez", Terminal 2, Venustiano Carranza, 15626, Ciudad de México, Mexico.
Travel Med Infect Dis. 2022 Sep-Oct;49:102361. doi: 10.1016/j.tmaid.2022.102361. Epub 2022 May 29.
SARS-CoV-2 continues to have a high rate of contagion worldwide. The new variant of concern, Omicron, has mutations that decrease the effectiveness of vaccines and evade antibodies from previous infections resulting in a fourth wave of the pandemic. It was identified in Mexico in December 2021.
The Traveler's Preventive Care Clinic from the Faculty of Medicine UNAM at Mexico City International Airport has performed rapid antigen and PCR SARS CoV2 tests since January 2021 to comply with the new travel requirements. Demographic and clinical characteristics were collected from each passenger and the fourth wave of the pandemic in Mexico mainly caused by Omicron was analyzed in the travelers.
A total of 5176 travelers attended the clinic between the second half of December 2021 and January 2022. Ten percent of all the tests performed were positive (13% of PCR and 9.3% of antigens, p = 0.001). Most of the SARS CoV2 positive cases were asymptomatic (78%), with a ratio of 3.5:1 over the symptomatic. By age groups, this ratio was higher for those under 20 years old (8.7:1).
This study shows the rapid escalation of positivity that occurred in Mexico, detected in travelers, from the second half of December 2020 and throughout the month of January 2021. The incidence of COVID-19 was extremely high in travelers who were mostly asymptomatic for the period under study.
SARS-CoV-2 继续在全球范围内具有很高的传染性。新的关注变体奥密克戎（Omicron）具有降低疫苗有效性和逃避先前感染产生的抗体的突变，导致大流行的第四波。它于 2021 年 12 月在墨西哥被发现。
墨西哥城国际机场的 UNAM 医学院旅行者预防保健诊所自 2021 年 1 月以来一直在进行快速抗原和 PCR SARS CoV2 检测，以符合新的旅行要求。从每位乘客那里收集人口统计学和临床特征，并分析旅行者中墨西哥大流行的第四波主要由奥密克戎引起的情况。
2021 年 12 月下旬至 2022 年 1 月期间，共有 5176 名旅行者参加了该诊所。进行的所有检测中，有 10%呈阳性（PCR 的 13%和抗原的 9.3%，p=0.001）。大多数 SARS CoV2 阳性病例为无症状（78%），与有症状的病例相比，其比例为 3.5:1。按年龄组划分，20 岁以下的比例更高（8.7:1）。
本研究显示，2020 年 12 月下旬至 2021 年 1 月期间，旅行者在墨西哥的阳性率迅速上升，这在旅行者中被检测到。在研究期间，旅行者中 COVID-19 的发病率极高，且大多数无症状。
