SummaryThe present study investigated serum immunoglobulin (Ig) concentrations in relation to demographic factors, common habits (alcohol consumption and smoking) and metabolic abnormalities in an adult population-based survey including 460 individuals. Serum levels of interleukin (IL)-6, a marker of inflammation, were also determined. After adjusting for confounders, male sex was associated positively with IgA levels and negatively with IgM levels. Age was associated positively with IgA and IgG levels. Smoking was associated negatively with IgG levels. Heavy drinking was associated positively with IgA levels. Metabolic abnormalities (obesity and metabolic syndrome) were associated positively with IgA levels. Abdominal obesity and hypertriglyceridaemia were the components of metabolic syndrome associated most strongly with serum IgA. Heavy drinkers with metabolic syndrome showed particularly high serum IgA levels. Serum IL-6 levels were correlated positively with IgA and IgG concentrations. It is concluded that sex, age, alcohol consumption, smoking and common metabolic abnormalities should be taken into account when interpreting serum levels of IgA, IgG and IgM.

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.

Alcohol consumption above a certain threshold is associated with an increase in total serum IgE levels. Alcohol consumption may also be associated with an increased prevalence of pollen sensitization.

Discontinuation of HAART after 1 year of successful treatment is followed by a rapid rebound of viral load; this rapidly returns to undetectable levels following reintroduction of the same treatment. In patients with more effective control of virus replication (viremia below 5 copise/ml), discontinuation of treatment was associated with more severe impairment of immunologic parameters.