ImportanceSARS-CoV-2 infection is associated with persistent, relapsing, or new symptoms or other health effects occurring after acute infection, termed postacute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. Characterizing PASC requires analysis of prospectively and uniformly collected data from diverse uninfected and infected individuals.ObjectiveTo develop a definition of PASC using self-reported symptoms and describe PASC frequencies across cohorts, vaccination status, and number of infections.Design, Setting, and ParticipantsProspective observational cohort study of adults with and without SARS-CoV-2 infection at 85 enrolling sites (hospitals, health centers, community organizations) located in 33 states plus Washington, DC, and Puerto Rico. Participants who were enrolled in the RECOVER adult cohort before April 10, 2023, completed a symptom survey 6 months or more after acute symptom onset or test date. Selection included population-based, volunteer, and convenience sampling.ExposureSARS-CoV-2 infection.Main Outcomes and MeasuresPASC and 44 participant-reported symptoms (with severity thresholds).ResultsA total of 9764 participants (89% SARS-CoV-2 infected; 71% female; 16% Hispanic/Latino; 15% non-Hispanic Black; median age, 47 years [IQR, 35-60]) met selection criteria. Adjusted odds ratios were 1.5 or greater (infected vs uninfected participants) for 37 symptoms. Symptoms contributing to PASC score included postexertional malaise, fatigue, brain fog, dizziness, gastrointestinal symptoms, palpitations, changes in sexual desire or capacity, loss of or change in smell or taste, thirst, chronic cough, chest pain, and abnormal movements. Among 2231 participants first infected on or after December 1, 2021, and enrolled within 30 days of infection, 224 (10% [95% CI, 8.8%-11%]) were PASC positive at 6 months.Conclusions and RelevanceA definition of PASC was developed based on symptoms in a prospective cohort study. As a first step to providing a framework for other investigations, iterative refinement that further incorporates other clinical features is needed to support actionable definitions of PASC.

Concrete biodeterioration is defined as the damage that the products of microorganism metabolism, in particular sulfuric acid, do to hardened concrete. In Canada and in the northern part of the United States, sewer failures from concrete biodeterioration are almost unknown. In the southern part of the United States and in Mexico, however, it is a serious and expensive problem in sewage collection systems, which rapidly deteriorate. Also, leaking sewage systems result in the loss of groundwater resources particularly important in this arid region. Almost every city in the Mexican-American border region, who's combined population is more than 15 million people, faces this problem. The U.S. cities have made some provision to face these infrastructure problems, but the Mexican cities have made less effort. We recommend here the Mexican norm (NMX-C-414-ONNCCE-2004) [1] to be reviewed, or at least that a warning be issued as a key measure to avoid concrete biodeterioration.

The damage that the products of microorganism metabolism, in particular biogenic sulfuric acid, do to hardened concrete is known as concrete biodeterioration. These microorganisms, Acidithiobacillus thiooxidans, Acidithiobacillus ferrooxidans and sulfate-reducing bacteria (SRB) are ubiquitous in the environment and they produce either hydrogen sulfide or sulfuric acid that can dissolve and disintegrate the concrete matrix. Their activity plays a very important function in the whole spectrum of degradation processes such as corrosion of reinforced metals and concrete.In Canada and in the northern part of the United States, concrete structure failures from concrete biodeterioration are less common than in the southern part of the United States and in Mexico, nevertheless, it is a serious and expensive problem in hydraulic structures and sewage collection systems, which rapidly deteriorate. Also, leaking sewage systems result in the loss of groundwater resources particularly important in this arid region. Almost every city in the Mexican-American border region, who’s combined population is more than 15 million people, faces this problem. The U.S. cities have made some provision to face these concrete structure problems, but the Mexican cities have made less effort. Additives and admixtures are used to improve the properties of the concrete; nonetheless, we have exposed here the importance of the factual composition of the Portland cement and concrete to mitigate concrete biodeterioration in the hydraulic structures and sewage collection systems.