Soriano Vicente, Ganado-Pinilla Pilar, Sanchez-Santos Miguel, Gómez-Gallego Felix, Barreiro Pablo, de Mendoza Carmen, Corral Octavio
UNIR Health Sciences School and Medical Centre, Madrid, Spain.
UNIR Health Sciences School and Medical Centre, Madrid, Spain.
Int J Infect Dis. 2021 Apr;105:374-376. doi: 10.1016/j.ijid.2021.02.115. Epub 2021 Mar 5.
The emergence and rapid global spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) represents a major challenge to health services, and has disrupted social and economic activities worldwide. In Spain, the first pandemic wave started in mid-March 2020 and lasted for 3 months, requiring home confinement and strict lockdown. Following relaxation of the measures during the summer, a second wave commenced in mid-September 2020 and extended until Christmas 2020.
The two pandemic waves were compared using information collected from rapid diagnostic tests and polymerase chain reaction assays at one university clinic in Madrid, the epicentre of the pandemic in Spain.
In total, 1569 individuals (968 during the first wave and 601 during the second wave) were tested for SARS-CoV-2-specific antibodies using fingerprick capillary blood. In addition, during the second wave, 346 individuals were tested for SARS-CoV-2-specific antigen using either oral swabs or saliva. The overall seroprevalence of first-time-tested individuals was 12.6% during the first wave and 7.7% during the second wave (P < 0.01). Seroconversions and seroreversions within 6 months occurred at low rates, both below 5%. During the second wave, 3.5% of tested individuals were SARS-CoV-2 antigen positive, with two cases considered as re-infections. Severe clinical symptoms occurred in a greater proportion of cases during the first wave compared with the second wave (27.8% vs 10.6%, respectively; P = 0.03).
The cumulative seroprevalence of SARS-CoV-2 antibodies in Madrid at the end of 2020 was approximately 20%. Seroreversions within 6 months occurred in 4% of cases. Seroconversions and re-infections were clinically less severe during the second wave than during the first wave. Hypothetically, a lower viral inoculum as a result of social distancing, increased use of face masks, promotion of outdoor activities and restrictions on gatherings may have contributed to this lower pathogenicity.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的出现及其在全球的迅速传播对卫生服务构成了重大挑战，并扰乱了全球的社会和经济活动。在西班牙，第一波疫情于2020年3月中旬开始，持续了3个月，要求居家隔离和严格封锁。夏季措施放松后，第二波疫情于2020年9月中旬开始，一直持续到2020年圣诞节。
利用西班牙疫情中心马德里一家大学诊所从快速诊断测试和聚合酶链反应检测中收集的信息，对这两波疫情进行比较。
总共对1569人（第一波968人，第二波601人）进行了SARS-CoV-2特异性抗体的指尖毛细血管血检测。此外，在第二波疫情期间，对346人进行了口腔拭子或唾液的SARS-CoV-2特异性抗原检测。首次检测个体的总体血清阳性率在第一波疫情期间为12.6%，在第二波疫情期间为7.7%（P<0.01）。6个月内的血清转化和血清逆转发生率较低，均低于5%。在第二波疫情期间，3.5%的检测个体SARS-CoV-2抗原呈阳性，有两例被视为再次感染。与第二波疫情相比，第一波疫情期间出现严重临床症状的病例比例更高（分别为27.8%和10.6%；P=0.03）。
2020年底马德里SARS-CoV-2抗体的累积血清阳性率约为20%。4%的病例在6个月内出现血清逆转。第二波疫情期间的血清转化和再次感染在临床上比第一波疫情期间的症状较轻。据推测，社交距离加大、口罩使用增加、户外活动推广和集会限制导致病毒接种量降低，可能是致病性降低的原因。
