tetano
Editor, Senior Moderator
Int J Infect Dis
. 2021 Mar 5;S1201-9712(21)00201-0.
doi: 10.1016/j.ijid.2021.02.115. Online ahead of print.
Main Differences Between the First and Second Waves of COVID-19 in Madrid, Spain
Vicente Soriano[SUP] 1 [/SUP], Pilar Ganado-Pinilla[SUP] 2 [/SUP], Miguel Sanchez-Santos[SUP] 2 [/SUP], Felix G?mez-Gallego[SUP] 2 [/SUP], Pablo Barreiro[SUP] 3 [/SUP], Carmen de Mendoza[SUP] 4 [/SUP], Octavio Corral[SUP] 2 [/SUP]
Affiliations
Abstract
Background: The surge and rapid global spreading of SARS-CoV-2 infection has deeply challenged health services and disrupted social and economic activities worldwide. In Spain, the arrival of the first pandemic wave occurred in mid-March 2020 and lasted for 3 months, being abated with home confinement and strict lockdown. After relaxing measures during summer, a second wave began in mid-September and extended until Christmas 2020.
Methods: We compared the main features of SARS-CoV-2 infections during the two pandemic waves. We examined the information collected with rapid diagnostic tests and PCR at one university clinic in Madrid, epicenter of the pandemic in Spain.
Results: A total of 1569 individuals (968 during the 1[SUP]st[/SUP] wave and 601 during the 2[SUP]nd[/SUP] wave) were tested for SARS-CoV-2 specific antibodies using finger prick capillary blood. In addition, during the second wave, 346 persons were tested for SARS-CoV-2 specific antigens using either oral swab or saliva. The overall seroprevalence of first-time tested persons was 12.6% during the 1[SUP]st[/SUP] wave and 7.7% during the 2[SUP]nd[/SUP] wave (p < 0.01). Seroconversions and seroreversions were noticed within 6 months at low rates, both below 5%. Positive SARS-CoV-2 antigen during the 2[SUP]nd[/SUP] wave was recognized in 3.5% of tested individuals, being two cases considered as reinfections. Severe clinical symptoms occurred in a greater proportion during the first wave compared to the second wave (27.8% vs 10.6%, respectively; p = 0.03).
Conclusion: The cumulative seroprevalence of SARS-CoV-2 antibodies in Madrid at the end of year 2020 was around 20%. Seroreversions within six months occurred in 4%. Seroconversions and reinfections during the second wave were clinically less severe than during the 1[SUP]st[/SUP] wave. Hypothetically, promotion of wider face masking, outdoor activities, and gathering restrictions during the 2nd wave most likely contributed to reduced exposures to large size inoculum.
Keywords: SARS-CoV-2; antibodies; coronavirus; prevalence; reinfections.
. 2021 Mar 5;S1201-9712(21)00201-0.
doi: 10.1016/j.ijid.2021.02.115. Online ahead of print.
Main Differences Between the First and Second Waves of COVID-19 in Madrid, Spain
Vicente Soriano[SUP] 1 [/SUP], Pilar Ganado-Pinilla[SUP] 2 [/SUP], Miguel Sanchez-Santos[SUP] 2 [/SUP], Felix G?mez-Gallego[SUP] 2 [/SUP], Pablo Barreiro[SUP] 3 [/SUP], Carmen de Mendoza[SUP] 4 [/SUP], Octavio Corral[SUP] 2 [/SUP]
Affiliations
- PMID: 33684560
- DOI: 10.1016/j.ijid.2021.02.115
Abstract
Background: The surge and rapid global spreading of SARS-CoV-2 infection has deeply challenged health services and disrupted social and economic activities worldwide. In Spain, the arrival of the first pandemic wave occurred in mid-March 2020 and lasted for 3 months, being abated with home confinement and strict lockdown. After relaxing measures during summer, a second wave began in mid-September and extended until Christmas 2020.
Methods: We compared the main features of SARS-CoV-2 infections during the two pandemic waves. We examined the information collected with rapid diagnostic tests and PCR at one university clinic in Madrid, epicenter of the pandemic in Spain.
Results: A total of 1569 individuals (968 during the 1[SUP]st[/SUP] wave and 601 during the 2[SUP]nd[/SUP] wave) were tested for SARS-CoV-2 specific antibodies using finger prick capillary blood. In addition, during the second wave, 346 persons were tested for SARS-CoV-2 specific antigens using either oral swab or saliva. The overall seroprevalence of first-time tested persons was 12.6% during the 1[SUP]st[/SUP] wave and 7.7% during the 2[SUP]nd[/SUP] wave (p < 0.01). Seroconversions and seroreversions were noticed within 6 months at low rates, both below 5%. Positive SARS-CoV-2 antigen during the 2[SUP]nd[/SUP] wave was recognized in 3.5% of tested individuals, being two cases considered as reinfections. Severe clinical symptoms occurred in a greater proportion during the first wave compared to the second wave (27.8% vs 10.6%, respectively; p = 0.03).
Conclusion: The cumulative seroprevalence of SARS-CoV-2 antibodies in Madrid at the end of year 2020 was around 20%. Seroreversions within six months occurred in 4%. Seroconversions and reinfections during the second wave were clinically less severe than during the 1[SUP]st[/SUP] wave. Hypothetically, promotion of wider face masking, outdoor activities, and gathering restrictions during the 2nd wave most likely contributed to reduced exposures to large size inoculum.
Keywords: SARS-CoV-2; antibodies; coronavirus; prevalence; reinfections.