Using Primary Care Clinical Text Data and Natural Language Processing to Identify Indicators of COVID-19 in Toronto, Canada.

The objective of this study was to investigate whether a rule-based natural language processing (NLP) system, applied to primary care clinical text data, could be used to monitor COVID-19 viral activity in Toronto, Canada. We employed a retrospective cohort design. We included primary care patients with a clinical encounter between January 1, 2020 and December 31, 2020 at one of 44 participating clinical sites. During the study timeframe, Toronto first experienced a COVID-19 outbreak between March-2020 and June-2020; followed by a second viral resurgence from October-2020 through December-2020. We used an expert derived dictionary, pattern matching tools and contextual analyzer to classify primary care documents as 1) COVID-19 positive, 2) COVID-19 negative, or 3) unknown COVID-19 status. We applied the COVID-19 biosurveillance system across three primary care electronic medical record text streams: 1) lab text, 2) health condition diagnosis text and 3) clinical notes. We enumerated COVID-19 entities in the clinical text and estimated the proportion of patients with a positive COVID-19 record. We constructed a primary care COVID-19 NLP-derived time series and investigated its correlation with independent/external public health series: 1) lab confirmed COVID-19 cases, 2) COVID-19 hospitalizations, 3) COVID-19 ICU admissions, and 4) COVID-19 intubations. A total of 196,440 unique patients were observed over the study timeframe, of which 4,580 (2.3%) had at least one positive COVID-19 document in their primary care electronic medical record. Our NLP-derived COVID-19 time series describing the temporal dynamics of COVID-19 positivity status over the study timeframe demonstrated a pattern/trend which strongly mirrored that of other external public health series under investigation. We conclude that primary care text data passively collected from electronic medical record systems represent a high quality, low-cost source of information for monitoring/surveilling COVID-19 impacts on community health.

Patient visits and prescriptions for attention-deficit/hyperactivity disorder from 2017-2021: Impacts of COVID-19 pandemic in primary care.

OBJECTIVE: To determine whether more patients presented with Attention-deficit/hyperactivity disorder (ADHD)-related visits and/or sought care from family physicians more frequently during the COVID-19 pandemic. METHODS: Electronic medical records from the University of Toronto Practice-Based Research Network were used to characterize changes in family physician visits and prescriptions for ADHD medications. Annual patient prevalence and visit rates pre-pandemic (2017-2019) were used to calculate the expected rates in 2020 and 2021. The expected and observed rates were compared to identify any pandemic-related changes. RESULTS: The number of patients presenting for ADHD-related visits during the pandemic was consistent with pre-pandemic trends. However, observed ADHD-related visits in 2021 were 1.32 times higher than expected (95% CI: 1.05-1.75), suggesting that patients visited family physicians more frequently than before the pandemic. CONCLUSION: Demand for primary care services related to ADHD has continued to increase during the pandemic, with increased health service use among those accessing care.

Coronavirus disease 2019 vaccine effectiveness among a population-based cohort of people living with HIV.

OBJECTIVE: People with HIV were underrepresented in coronavirus disease 2019 (COVID-19) vaccine clinical trials. We estimated vaccine effectiveness (VE) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection for the BNT162b2, mRNA-1273, and ChAdOx1 vaccines among a population-based cohort of people with HIV in Ontario, Canada. DESIGN: Test-negative design. METHODS: We identified people with HIV aged ≥19 years who were tested for SARS-CoV-2 by RT-PCR between December 14, 2020 (first availability of COVID-19 vaccines) and November 21, 2021 (pre-Omicron circulation). Outcomes included any infection, symptomatic infection, and COVID-19-related hospitalization/death. We compared the odds of vaccination between test-positive cases and test-negative controls using multivariable logistic regression with adjustment for age, sex, region, calendar time, SARS-CoV-2 test histories, influenza vaccination, comorbidities, and neighborhood-level socio-economic status. VE was derived as (1 - adjusted odds ratio) × 100%. RESULTS: Among 21 023 adults living with HIV, there were 801 (8.3%) test-positive cases and 8,879 (91.7%) test-negative controls. 20.1% cases and 47.8% of controls received ≥1 COVID-19 vaccine dose; among two-dose recipients, 93.4% received ≥1 mRNA dose. Two-dose VE ≥7 days before specimen collection was 82% (95% confidence interval [CI] = 74-87%) against any infection, 94% (95% CI = 82-98%) against symptomatic infection, and 97% (95% CI = 85-100%) against hospitalization/death. Against any infection, VE declined from 86% (95% CI = 77-92%) within 7-59 days after the second dose to 66% (95% CI = -15-90%) after ≥180 days; we did not observe evidence of waning protection for other outcomes. CONCLUSION: Two doses of COVID-19 vaccine offered substantial protection against symptomatic illness and hospitalization/death in people with HIV prior to the emergence of the Omicron variant. Our findings do not support a broad conclusion that COVID-19 VE is lower among people with HIV in populations that, for the most part, are attending HIV care, taking antiretroviral medication, and are virally suppressed.

The Impact of a Clinical Decision Support System for Addressing Physical Activity and Healthy Eating During Smoking Cessation Treatment: Hybrid Type I Randomized Controlled Trial.

BACKGROUND: People who smoke have other risk factors for chronic diseases, such as low levels of physical activity and poor diet. Clinical decision support systems (CDSSs) might help health care practitioners integrate interventions for diet and physical activity into their smoking cessation programming but could worsen quit rates. OBJECTIVE: The aims of this study are to assess the effects of the addition of a CDSS for physical activity and diet on smoking cessation outcomes and to assess the implementation of the study. METHODS: We conducted a pragmatic hybrid type I effectiveness-implementation trial with 232 team-based primary care practices in Ontario, Canada, from November 2019 to May 2021. We used a 2-arm randomized controlled trial comparing a CDSS addressing physical activity and diet to treatment as usual and used the Reach, Effectiveness, Adoption, Implementation, and Maintenance framework to measure implementation outcomes. The primary outcome was self-reported 7-day tobacco abstinence at 6 months. RESULTS: We enrolled 5331 participants in the study. Of these, 2732 (51.2%) were randomized to the intervention group and 2599 (48.8%) to the control group. At the 6-month follow-up, 29.7% (634/2137) of respondents in the intervention arm and 27.3% (552/2020) in the control arm reported abstinence from tobacco. After multiple imputation, the absolute group difference was 2.1% (95% CI -0.5 to 4.6; F1,1000.42=2.43; P=.12). Mean exercise minutes changed from 32 (SD 44.7) to 110 (SD 196.1) in the intervention arm and from 32 (SD 45.1) to 113 (SD 195.1) in the control arm (group effect: B=-3.7 minutes; 95% CI -17.8 to 10.4; P=.61). Servings of fruit and vegetables changed from 2.64 servings to 2.42 servings in the intervention group and from 2.52 servings to 2.45 servings in the control group (incidence rate ratio for intervention group=0.98; 95% CI 0.93-1.02; P=.35). CONCLUSIONS: A CDSS for physical activity and diet may be added to a smoking cessation program without affecting the outcomes. Further research is needed to improve the impact of integrated health promotion interventions in primary care smoking cessation programs. TRIAL REGISTRATION: ClinicalTrials.gov NCT04223336 https://www.clinicaltrials.gov/ct2/show/NCT04223336. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/19157.

Family Physicians Stopping Practice During the COVID-19 Pandemic in Ontario, Canada.

We conducted 2 analyses using administrative data to understand whether more family physicians in Ontario, Canada stopped working during the COVID-19 pandemic compared with previous years. First, we found 3.1% of physicians working in 2019 (n = 385/12,247) reported no billings in the first 6 months of the pandemic; compared with other family physicians, a higher portion were aged 75 years or older (13.0% vs 3.4%, P <0.001), had fee-for-service reimbursement (37.7% vs 24.9%, P <0.001), and had a panel size under 500 patients (40.0% vs 25.8%, P <0.001). Second, a fitted regression line found the absolute increase in the percentage of family physicians stopping work was 0.03% per year from 2010 to 2019 (P = 0.042) but 1.2% between 2019 to 2020 (P <0.001). More research is needed to understand the impact of physicians stopping work on primary care attachment and access to care.

Impact of the COVID-Pandemic on Diabetes Screening from 20to 2021 in Ontario, Canada

Diabetes incidence is expected to increase following the COVID-pandemic due to widespread changes in physical activity, diet, and access to health care services. We used administrative health care databases from Ontario, Canada to examine monthly changes in diabetes screening during the pandemic (Mar 2020-Feb 2021) compared to the pre-pandemic period (Mar 2019-Feb 2020) among adults aged 20-85 without prior diabetes. The eligible population was 9,599,079 in Mar 20 and 9,941,336 in Feb 2021. Overall, the number of people screened for diabetes was 25.3% lower in the pandemic (N=4,060,348) versus pre-pandemic (N=5,437,284) period. However, the number of people screened each month declined by 65.6% between February and April 2020 (Figure 1;1.53 vs. 4.44 per 100, -2.91 per 100) . Screening rates recovered by July 2020 (3.88 per 100) but remained 15.6% lower than in the pre-pandemic period. Similar patterns were observed in all age groups but declines in screening rates between February and April 2020 were greatest in adults aged 35-49 (-69.4%) and 50-64 (-69.5%) . Findings were also consistent across income groups. In summary, we observed a sudden decline in diabetes screening in Ontario, Canada, where laboratory tests and other health care services are universally insured. This may lead to delays in prediabetes and diabetes diagnosis, resulting in missed opportunities for diabetes prevention and early management.

A mindfulness-based intervention for student depression, anxiety, and stress: Randomized controlled trial

Background: University students are experiencing higher levels of distress and mental health disorders than before. In addressing mental health needs, web-based interventions have shown increasing promise in overcoming geographic distances and high student-to-counselor ratios, leading to the potential for wider implementation. The Mindfulness Virtual Community (MVC) program, a web-based program, guided by mindfulness and cognitive behavioral therapy principles, is among efforts aimed at effectively and efficiently reducing symptoms of depression, anxiety, and perceived stress in students. Objective: This study's aim was to evaluate the efficacy of an 8-week MVC program in reducing depression, anxiety, and perceived stress (primary outcomes), and improving mindfulness (secondary outcome) in undergraduate students at a large Canadian university. Guided by two prior randomized controlled trials (RCTs) that each demonstrated efficacy when conducted during regular university operations, this study coincided with a university-wide labor strike. Nonetheless, the students' response to an online mental health program on a disrupted campus can provide useful information for anticipating the impact of other disruptions, including those related to the COVID-19 pandemic as well as future disruptions. Methods: In this parallel-arm RCT, 154 students were randomly allocated to an 8-week MVC intervention (n = 76) or a wait-list control (WLC) condition (n = 78). The MVC intervention included the following: (1) educational and mindfulness video modules, (2) anonymous peer-to-peer discussions, and (3) anonymous, group-based, professionally guided, 20-minute videoconferences. Study outcomes were evaluated at baseline and at 8-week follow-up using the following: Patient Health Questionnaire-9 (PHQ-9), the Beck Anxiety Inventory (BAI), the Perceived Stress Scale (PSS), and the Five Facets Mindfulness Questionnaire Short Form (FFMQ-SF). Generalized estimation equations with an AR (1) covariance structure were used to evaluate the impact of the intervention, with outcome evaluations performed on both an intention-to-treat (ITT) and per-protocol (PP) basis. Results: Participants (n = 154) included 35 males and 117 females with a mean age of 23.1 years. There were no statistically significant differences at baseline between the MVC and WLC groups on demographics and psychological characteristics, indicating similar demographic and psychological characteristics across the two groups. Results under both ITT and PP approaches indicated that there were no statistically significant between-group differences in PHQ-9 (ITT: beta = -0.44, P = .64;PP: beta = -0.62, P = .053), BAI (ITT: beta = -2.06, P = .31;PP: beta = -2.32, P = .27), and FFMQ-SF (ITT: beta = 1.33, P = .43;PP: beta = 1.44, P = .41) compared to WLC. There was a significant difference for the PSS (ITT: beta = -2.31, P = .03;PP: beta = -2.38, P = .03). Conclusions: During a university labor strike, the MVC program led to statistically significant reductions in PSS compared to the WLC group, but there were no other significant between-group differences. Comparisons with previous cycles of intervention testing, undertaken during nondisrupted university operations, when efficacy was demonstrated, are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved)

Impact of the CARD (Comfort Ask Relax Distract) system on school-based vaccinations: A cluster randomized trial.

BACKGROUND: The CARD (Comfort Ask Relax Distract) system is a vaccine delivery framework that integrates evidence-based interventions to reduce stress-related responses and improve the vaccination experience for children undergoing vaccinations at school. In preliminary studies, CARD was acceptable and effective. The objective was to evaluate CARD in a large, pragmatic trial to confirm its effectiveness in real-world settings. METHODS: Hybrid effectiveness-implementation cluster randomized trial in schools receiving vaccination services from Wellington-Dufferin-Guelph Public Health. Forty schools with grade 7 students (12 years old) were randomized to CARD and control (n = 20/group). Nurses in CARD schools planned clinics with principals and educated students about CARD ahead of time. Principals disseminated information to staff and parents and sent reminders. Vaccination day processes minimized fear and facilitated student self-selected coping strategies. Nurses in control schools followed usual practices, which excluded principal meetings, education, reminders, and systematic integration of fear-reducing or child-selected coping strategies. Outcomes included stress-related symptoms (fear - primary outcome, pain, dizziness, fainting, post-vaccination reactions), use of coping interventions, vaccination uptake, attitudes and implementation outcomes (acceptability, appropriateness, feasibility, fidelity). RESULTS: Altogether, 1919 students were included. Fear and pain were lower in CARD schools: OR 0.65 (95% CI 0.47-0.90) and OR 0.62 (95% CI 0.50-0.77), respectively. No students fainted in CARD schools compared to 0.8% in control (p = 0.02). Dizziness and post-vaccination reactions did not differ. Student-led coping interventions were used more frequently in CARD schools. Vaccination uptake was 76.1% in CARD schools and 72.5% in control schools (OR 1.13 (95% CI 0.85-1.50)). Staff and students had positive attitudes about CARD and implementation outcomes; however, recommendations were made to improve fidelity. DISCUSSION: CARD reduced stress-related responses in students undergoing vaccinations at school and was positively received by students and public health staff. CARD is recommended to improve the quality of vaccination delivery services. TRIAL REGISTRATION: NCT03966300.

Non-negative matrix factorization temporal topic models and clinical text data identify COVID-19 pandemic effects on primary healthcare and community health in Toronto, Canada.

OBJECTIVE: To demonstrate how non-negative matrix factorization can be used to learn a temporal topic model over a large collection of primary care clinical notes, characterizing diverse COVID-19 pandemic effects on the physical/mental/social health of residents of Toronto, Canada. MATERIALS AND METHODS: The study employs a retrospective open cohort design, consisting of 382,666 primary care progress notes from 44,828 patients, 54 physicians, and 12 clinics collected 01/01/2017 through 31/12/2020. Non-negative matrix factorization uncovers a meaningful latent topical structure permeating the corpus of primary care notes. The learned latent topical basis is transformed into a multivariate time series data structure. Time series methods and plots showcase the evolution/dynamics of learned topics over the study period and allow the identification of COVID-19 pandemic effects. We perform several post-hoc checks of model robustness to increase trust that descriptive/unsupervised inferences are stable over hyper-parameter configurations and/or data perturbations. RESULTS: Temporal topic modelling uncovers a myriad of pandemic-related effects from the expressive clinical text data. In terms of direct effects on patient-health, topics encoding respiratory disease symptoms display altered dynamics during the pandemic year. Further, the pandemic was associated with a multitude of indirect patient-level effects on topical domains representing mental health, sleep, social and familial dynamics, measurement of vitals/labs, uptake of prevention/screening maneuvers, and referrals to medical specialists. Finally, topic models capture changes in primary care practice patterns resulting from the pandemic, including changes in EMR documentation strategies and the uptake of telemedicine. CONCLUSION: Temporal topic modelling applied to a large corpus of rich primary care clinical text data, can identify a meaningful topical/thematic summarization which can provide policymakers and public health stakeholders a passive, cost-effective, technology for understanding holistic impacts of the COVID-19 pandemic on the primary healthcare system and community/public-health.

A Population-Based Study of COVID-19 Infection Among Childhood Cancer Survivors.

Childhood cancer survivors are known to be at risk of chronic co-morbidities, although their risk of COVID-19 infection remains uncertain. Understanding the risk of COVID-19 in this population is necessary to counsel survivors and inform potential mitigation strategies. The objective of this study was to determine whether the rates of COVID-19 infection differed between childhood cancer survivors and the general population. Administrative health care data from a population-based registry of children and adolescents diagnosed with cancer in Ontario, Canada, were linked with a universal health insurance registry and a repository of laboratory data. Rates of COVID-19 testing, test positivity and infection between March 1, 2020 and March 31, 2021 among childhood cancer survivors (n = 10 242) were compared to matched controls from the general population (n = 49 068). Compared to the general population, childhood cancer survivors were more likely to have COVID-19 testing (35.9% [95% CI, 34.5-37.4%] vs. 32.0% [95% CI, 31.4-32.6%]), but had a lower likelihood of positive COVID-19 result among those tested (4.3% [95% CI, 3.6-4.9%] vs. 5.5% [95% CI, 5.1-5.8%]) and a similar rate of infection among all subjects at risk (1.5% [95% CI, 1.3-1.8%] vs. 1.7% [95% CI, 1.6-1.9%]). These findings can inform counseling of survivors and clinician recommendations for this population.

Postpartum mental illness during the COVID-19 pandemic: a population-based, repeated cross-sectional study.

BACKGROUND: It is unclear whether the clinical burden of postpartum mental illness has increased during the COVID-19 pandemic. We sought to compare physician visit rates for postpartum mental illness in Ontario, Canada, during the pandemic with rates expected based on prepandemic patterns. METHODS: In this population-based, repeated cross-sectional study using linked health administrative databases in Ontario, Canada, we used negative binomial regression to model expected visit rates per 1000 postpartum people for March-November 2020 based on prepandemic data (January 2016-February 2020). We compared observed visit rates to expected visit rates for each month of the pandemic period, generating absolute rate differences, incidence rate ratios (IRRs) and their 95% confidence intervals (CIs). The primary outcome was a visit to a primary care physician or a psychiatrist for any mental disorder. We stratified analyses by maternal sociodemographic characteristics. RESULTS: In March 2020, the visit rate was 43.5/1000, with a rate difference of 3.11/1000 (95% CI 1.25-4.89) and an IRR of 1.08 (95% CI 1.03-1.13) compared with the expected rate. In April, the rate difference (10.9/1000, 95% CI 9.14-12.6) and IRR (1.30, 95% CI 1.24-1.36) were higher; this level was generally sustained through November 2020. From April-November, we observed elevated visit rates across provider types and for diagnoses of anxiety, depressive and alcohol or substance use disorders. Observed increases from expected visit rates were greater for people 0-90 days postpartum compared with 91-365 days postpartum; increases were small among people living in low-income neighbourhoods. Public health units in the northern areas of the province did not see sustained elevations in visit rates after July; southern health units had elevated rates through to November. INTERPRETATION: Increased visits for mental health conditions among postpartum people during the first 9 months of the COVID-19 pandemic suggest an increased need for effective and accessible mental health care for this population as the pandemic progresses.

A Mindfulness-Based Intervention for Student Depression, Anxiety, and Stress: Randomized Controlled Trial.

BACKGROUND: University students are experiencing higher levels of distress and mental health disorders than before. In addressing mental health needs, web-based interventions have shown increasing promise in overcoming geographic distances and high student-to-counselor ratios, leading to the potential for wider implementation. The Mindfulness Virtual Community (MVC) program, a web-based program, guided by mindfulness and cognitive behavioral therapy principles, is among efforts aimed at effectively and efficiently reducing symptoms of depression, anxiety, and perceived stress in students. OBJECTIVE: This study's aim was to evaluate the efficacy of an 8-week MVC program in reducing depression, anxiety, and perceived stress (primary outcomes), and improving mindfulness (secondary outcome) in undergraduate students at a large Canadian university. Guided by two prior randomized controlled trials (RCTs) that each demonstrated efficacy when conducted during regular university operations, this study coincided with a university-wide labor strike. Nonetheless, the students' response to an online mental health program on a disrupted campus can provide useful information for anticipating the impact of other disruptions, including those related to the COVID-19 pandemic as well as future disruptions. METHODS: In this parallel-arm RCT, 154 students were randomly allocated to an 8-week MVC intervention (n=76) or a wait-list control (WLC) condition (n=78). The MVC intervention included the following: (1) educational and mindfulness video modules, (2) anonymous peer-to-peer discussions, and (3) anonymous, group-based, professionally guided, 20-minute videoconferences. Study outcomes were evaluated at baseline and at 8-week follow-up using the following: Patient Health Questionnaire-9 (PHQ-9), the Beck Anxiety Inventory (BAI), the Perceived Stress Scale (PSS), and the Five Facets Mindfulness Questionnaire Short Form (FFMQ-SF). Generalized estimation equations with an AR (1) covariance structure were used to evaluate the impact of the intervention, with outcome evaluations performed on both an intention-to-treat (ITT) and per-protocol (PP) basis. RESULTS: Participants (n=154) included 35 males and 117 females with a mean age of 23.1 years. There were no statistically significant differences at baseline between the MVC and WLC groups on demographics and psychological characteristics, indicating similar demographic and psychological characteristics across the two groups. Results under both ITT and PP approaches indicated that there were no statistically significant between-group differences in PHQ-9 (ITT: ß=-0.44, P=.64; PP: ß=-0.62, P=.053), BAI (ITT: ß=-2.06, P=.31; PP: ß=-2.32, P=.27), and FFMQ-SF (ITT: ß=1.33, P=.43; PP: ß=1.44, P=.41) compared to WLC. There was a significant difference for the PSS (ITT: ß=-2.31, P=.03; PP: ß=-2.38, P=.03). CONCLUSIONS: During a university labor strike, the MVC program led to statistically significant reductions in PSS compared to the WLC group, but there were no other significant between-group differences. Comparisons with previous cycles of intervention testing, undertaken during nondisrupted university operations, when efficacy was demonstrated, are discussed. TRIAL REGISTRATION: ISRCTN Registry ISRCTN92827275; https://www.isrctn.com/ISRCTN92827275.

Effectiveness of an 8-Week Web-Based Mindfulness Virtual Community Intervention for University Students on Symptoms of Stress, Anxiety, and Depression: Randomized Controlled Trial.

BACKGROUND: A student mental health crisis is increasingly acknowledged and will only intensify with the COVID-19 crisis. Given accessibility of methods with demonstrated efficacy in reducing depression and anxiety (eg, mindfulness meditation and cognitive behavioral therapy [CBT]) and limitations imposed by geographic obstructions and localized expertise, web-based alternatives have become vehicles for scaled-up delivery of benefits at modest cost. Mindfulness Virtual Community (MVC), a web-based program informed by CBT constructs and featuring online videos, discussion forums, and videoconferencing, was developed to target depression, anxiety, and experiences of excess stress among university students. OBJECTIVE: The aim of this study was to assess the effectiveness of an 8-week web-based mindfulness and CBT program in reducing symptoms of depression, anxiety, and stress (primary outcomes) and increasing mindfulness (secondary outcome) within a randomized controlled trial (RCT) with undergraduate students at a large Canadian university. METHODS: An RCT was designed to assess undergraduate students (n=160) who were randomly allocated to a web-based guided mindfulness-CBT condition (n=80) or to a waitlist control (WLC) condition (n=80). The 8-week intervention consisted of a web-based platform comprising (1) 12 video-based modules with psychoeducation on students' preidentified life challenges and applied mindfulness practice; (2) anonymous peer-to-peer discussion forums; and (3) anonymous, group-based, professionally guided 20-minute live videoconferences. The outcomes (depression, anxiety, stress, and mindfulness) were measured via an online survey at baseline and at 8 weeks postintervention using the Patient Health Questionnaire-9 (PHQ9), the Beck Anxiety Inventory (BAI), the Perceived Stress Scale (PSS), and the Five Facets Mindfulness Questionnaire Short Form (FFMQ-SF). Analyses employed generalized estimation equation methods with AR(1) covariance structures and were adjusted for possible covariates (gender, age, country of birth, ethnicity, English as first language, paid work, unpaid work, relationship status, physical exercise, self-rated health, and access to private mental health counseling). RESULTS: Of the 159 students who provided T1 data, 32 were males and 125 were females with a mean age of 22.55 years. Participants in the MVC (n=79) and WLC (n=80) groups were similar in sociodemographic characteristics at T1 with the exception of gender and weekly hours of unpaid volunteer work. At postintervention follow-up, according to the adjusted comparisons, there were statistically significant between-group reductions in depression scores (ß=-2.21, P=.01) and anxiety scores (ß=-4.82, P=.006), and a significant increase in mindfulness scores (ß=4.84, P=.02) compared with the WLC group. There were no statistically significant differences in perceived stress for MVC (ß=.64, P=.48) compared with WLC. CONCLUSIONS: With the MVC intervention, there were significantly reduced depression and anxiety symptoms but no significant effect on perceived stress. Online mindfulness interventions can be effective in addressing common mental health conditions among postsecondary populations on a large scale, simultaneously reducing the current burden on traditional counseling services. TRIAL REGISTRATION: ISRCTN Registry ISRCTN12249616; http://www.isrctn.com/ISRCTN12249616.