Determinants and Dynamics of SARS-CoV-2 Infection in a Diverse Population: 6-Month Evaluation of a Prospective Cohort Study

Abstract

Background We studied risk factors, antibody responses, and symptoms of SARS-CoV-2 infection in a diverse, ambulatory population. Methods A prospective cohort (n=831, including 548 hospital-based healthcare workers) previously undiagnosed with SARS-CoV-2 infection was followed for six months with serial testing (SARS-CoV-2 PCR, specific IgG) and surveys. Results 93 participants (11.2%) tested SARS-CoV-2-positive; 14 (15.1%) were asymptomatic and 24 (25.8%), severely symptomatic. Healthcare workers were more likely to become infected (14.2% vs. 5.3%, aOR 2.1, 95% CI 1.4-3.3) and have severe symptoms (29.5% vs. 6.7%). IgG antibodies were detected after 79% of asymptomatic infections, 89% with mild-moderate symptoms, and 96% with severe symptoms. IgG trajectories after asymptomatic infection (slow increases) differed from symptomatic infections (early peaks within 2 months). Most participants (92%) had persistent IgG responses (median 171 days). In multivariable models, IgG titers were positively associated with symptom severity, certain comorbidities, and hospital work. Dyspnea, altered smell and taste, and other neurologic changes persisted for ≥120 days in ≥10% of affected participants. Participants with prolonged symptoms (generally more severely symptomatic) had higher antibody levels. Conclusions In a prospective, ethnically diverse cohort, symptom severity correlated with the magnitude and trajectory of IgG production. Symptoms frequently persisted for many months after infection.

Persistence of SARS-CoV-2-Specific Antibodies for 13 Months after Infection

“…From 50 individuals who agreed to participate in the first testing, 45 had a positive RT-PCR result during the outbreak and 34 of them self-reported either asymptomatic or very mild or mild infection, while 11 self-reported moderate to severe COVID-19. The seropositivity rate after an asymptomatic SARS-CoV-2 infection was lower when compared to symptomatic infection of different severity, which is in line with other studies [26]. Another issue addressed during the first serological testing was related to the persistence of virus-specific IgM and its potential diagnostic value for an acute SARS-CoV-2 infection.…”

“…To date, both sero-epidemiological and targeted cohort studies from different countries have reported detectable levels of virus-specific antibodies and duration of the protective immune response from 3 to 13 months after infection [6,7,10,12,13,17,19,21,24,25]. Previous cohort studies on the formation and persistence of SARS-CoV-2-specific humoral immune response mainly included healthcare workers as a target group having the highest risk of being exposed to SARS-CoV-2 [13,14,16,19,20,24,26,27]. However, a long-term monitoring of antibody levels in naturally infected healthcare workers seems to be difficult or even impossible after the start of a global vaccination, as the healthcare sector is considered a priority group for vaccination in many countries [28].…”

Complications Post-COVID-19 and Risk Factors among Patients after Six Months of a SARS-CoV-2 Infection: A Population-Based Prospective Cohort Study

“…We have not observed an association between BMI, obesity, regular exercise, or alcohol consumption and post-COVID-19 symptoms, in contrast with other studies [31,53]. In addition, high levels of anti-SARS-CoV-2 antibodies or their increase between June 2020 and October 2020 were not associated with complications, recovery, and return to the usual health [33], contrary to other studies [25,28,57]. However, attendance of MGEs, observing a person with a cough at MGEs, and contact with a COVID-19 patient were associated with complications, inferior recovery, and less frequent return to usual health.…”

“…The frequency of complications subsequent to the acute phase has important variations in the ranges from 10% to 93% [3,5,8,[19][20][21][22][23][24][25]. The studies of post-COVID-19 complications are heterogeneous; including hospitalized versus non-hospitalized patients, with variable demographic characteristics of patients, the severity of the disease, follow-up time, different measures of the complications, control groups for comparison, designs, sample size, and statistical analysis [5,21,[26][27][28][29]. In this situation, accruing evidence on the frequency and the manifestation of LCS and related risk factors is needed [22,30,31].…”

Long-term immunologic effects of SARS-CoV-2 infection: leveraging translational research methodology to address emerging questions

“…So far, the clues have been limited. A handful of studies have identified higher levels of binding or neutralizing antibodies in those with PASC, 122,123 suggesting that persistent symptoms could be a manifestation of more severe illness (which is known to be associated with higher antibody levels and correlated with higher risk of developing PASC) or possibly persistent immune stimulation. 14 Other studies have found that the humoral response appears lower among those with persistent symptoms.…”