DISPATCHESS evere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly worldwide during 2020-2021, but incidence has been highly variable in different countries and is diffi cult to estimate. In Portugal, which has ≈10.3 million inhabitants, the burden of disease, cases, and deaths was similar to or less than that for neighboring countries during the fi rst wave of the coronavirus disease (COVID-19) pandemic, through September 2020 (Appendix Figure, https://wwwnc.cdc.gov/ EID/article/27/11/21-0636-App1.pdf). However, it is diffi cult to estimate the true extent of SARS-CoV-2 infections in Portugal, although a previous study of clinical patients indicated a seropositivity <2.9% (1). We report a national, cross-sectional, epidemiologic survey that used quota sampling to quantify more accurately the cumulative number of infected persons in Portugal. The StudyWe used a convenience quota sampling, quasi-proportional to the population of Portugal in 9 strata: age group (<18, 18-54, and >55 years of age), each subdivided by population density of place of residence (<60, 60-500, and >500 persons/km 2 ) (Appendix). After a widespread media campaign, we recruited participants by using voluntary registration on a website specifi cally designed for this study. We obtained informed consent from all participants >16 years of age and from legal guardians for participants <18 years of age. The study was approved by the Ethics Committee of the Centro Académico de Medicina de Lisboa (#350/20, July 30, 2020).Blood collections and serologic tests were performed by Centro de Medicina Laboratorial Germano de Sousa (Lisbon, Portugal) by using standard procedures. We determined total antibodies against SARS-CoV-2 by using a chemiluminescent immunoassay test (COV2T; Advia Centaur Siemens, https:// www.siemens-healthineers.com), which targets the spike protein. This antibody test has a sensitivity of 98.1% and a specifi city of 99.9% (2), which we used to correct the seroprevalence estimates by using the Rogan-Gladen estimator (3). We used sample weights and poststratifi ed by sex to adjust the seroprevalence, extrapolating from the strata to the whole population (Appendix Tables 1-4). Participants completed a questionnaire with demographic, clinical, and epidemiologic questions regarding SARS-CoV-2 exposure (Appendix). We use standard statistical analyses to compare results at an α = 0.05 signifi cance.We enrolled 13,398 participants (55.3% women, age range 1-92 years) (Appendix Figure 2). Our sample refl ected approximately the characteristics of the

During the COVID‐19 pandemic, Portugal has experienced three distinct SARS‐CoV‐2 infection waves. We previously documented the prevalence of SARS‐CoV‐2 immunity, measured by specific antibodies, in September 2020, 6 months after the initial moderate wave. Here, we show the seroprevalence changes 6 months later, up to the second week of March 2021, shortly following the third wave, which was one of the most severe in the world, and 2 months following the start of the vaccination campaign. A longitudinal epidemiological study was conducted, with a stratified quota sample of the Portuguese population. Serological testing was performed, including ELISA determination of antibody class and titers. The proportion of seropositives, which was 2.2% in September 2020, rose sharply to 17.3% (95% CI: 15.8–18.8%) in March 2021. Importantly, circulating IgG and IgA antibody levels were very stable 6 months after the initial determination and up to a year after initial infection, indicating long‐lasting infection immunity against SARS‐CoV‐2. Moreover, vaccinated people had higher IgG levels from 3 weeks post‐vaccination when compared with previously infected people at the same time post‐infection.

During the COVID-19 pandemic, Portugal has experienced three distinct SARS-CoV-2 infection waves. We previously documented the prevalence of SARS-CoV-2 immunity, measured by specific antibodies, in September 2020, six months after the initial moderate wave. Here we show the seroprevalence changes six months later, up to the second week of March 2021, shortly following the third wave, which was one of the most severe in the world, and two months following the start of the vaccination campaign. A longitudinal epidemiological study was conducted, with a stratified quota sample of the Portuguese population. Serological testing was performed, including ELISA determination of antibody class and titres. The proportion of seropositives, which was 2.2% in September 2020, rose sharply to 17.3% (95% CI: 15.8% – 18.8%) in March 2021. Importantly, circulating IgG and IgA antibody levels were very stable six months after the initial determination and up to a year after initial infection, indicating long-lasting natural immunity against SARS-CoV-2. Moreover, vaccinated people had higher IgG levels from 3 weeks post-vaccination when compared with previously infected people at the same times post-infection.

Green walls (GWs) have been increasingly recognized as an important restoration technique for steep slopes resulting from quarrying activities or major infrastructure construction projects. In practice, GW irrigation is considered essential, although studies evaluating vegetation establishment under different irrigation regimes are lacking. Besides taxonomic metrics, functional diversity measures were used to compare the diversity and composition of plant communities of two hydroseeded GWs, with different irrigation regimes (irrigated vs. low-irrigated). The studied GWs were installed in Peneda-Gerês National Park (NW Portugal) to minimize the visual impact of shotcrete walls, along a road infrastructure, and promote their ecological restoration. Species' cover was recorded 3 years after installation. Species were classified according to their growth form, life form, and life strategy. Despite hydroseeding approximately 57 species, GW vegetation was dominated by spontaneous species, particularly acrocarpous mosses, regardless of irrigation regime. Species and functional richness were higher under irrigated conditions, while no differences were observed for species diversity and functional dispersion. Functional trait composition did not differ between GWs, indicating that both systems potentially provide the same ecosystem functions and services. Our results also suggest that spontaneous species colonizing GWs are highly adapted to local environmental conditions, given their dominance in both irrigated and low-irrigated communities. Overall, irrigation did not affect the structure and functioning of GW communities, only their redundancy, since more species exhibiting similar traits were established in the irrigated GW. Therefore, our findings suggest that low-irrigated GWs, hydroseeded with native species, represent a more cost-effective solution to reduce the ecological impacts of steep slopes. Implications for Practice• Green wall irrigation promotes the establishment of plant communities with higher (species and functional) richness, without changes in functional composition. • Practitioners should consider hydroseeding green walls with native species (both vascular plants and bryophytes), in order to promote the provision of multiple ecosystem services and the conservation of local diversity. • On green wall systems, spontaneous colonization is a key component of community assembly, especially in areas surrounded by natural vegetation. As such, under favorable environmental conditions, the use of hydroseeding can be minimized. • Extensive, low-irrigated green walls represent an innovative solution for the ecological restoration of steep slopes.