Seeing the people clinic data miss, and answering the question rigorously once we do

We design and run large, geographically dispersed cohorts entirely online: recruitment, remote consent, longitudinal surveys, specimen kit fulfillment and return, laboratory integration, incentives and retention, and integrated survey and laboratory data. Participants self-collect specimens at home, and collection kits are transported to and from them through the mail. Specimens have included dried blood spots, saliva, and nasal, vaginal and rectal swabs.

The result is a cohort that can answer questions about infection, immunity, vaccine effectiveness and durability, natural history, and real-world outcomes in the general population, on a timeline measured in weeks rather than years. We bring to it decades of experience running traditional clinical cohorts.

Study designs we run:

• Prospective community-based cohorts
• Vaccine effectiveness and durability
• Seroprevalence with at-home dried blood spots
• Natural history and post-acute outcomes
• Post-authorization safety and effectiveness
• Burden of disease and health care use
• HIV prevention and PrEP cohorts
• Trials embedded within cohorts
• Target trial emulation
• Implementation strategy trials
• Rapid cohorts for emerging threats

When a randomized trial is not possible, not ethical, or not fast enough, target trial emulation is the most rigorous way to get a causal answer from observational data. We specify the trial we would run, with its eligibility criteria, treatment strategies, time zero, follow-up and outcomes, and then emulate it with cohort, electronic health record, claims or surveillance data, avoiding the design errors that bias many real-world studies.

We have used target trial emulation in many studies, including the effect of a third COVID-19 vaccine dose on long COVID and the natural history of symptoms after SARS-CoV-2 infection. It is increasingly what regulators, journals and guideline committees expect from real-world evidence, and it pairs naturally with the cohorts we run.

• Comparative effectiveness and safety
• Vaccine and treatment effects in real-world populations
• Effects of policies and large-scale exposures
• Study design and protocol review for sponsor RWE
• Reanalysis and peer review of existing RWE

An active cohort with collection kits already in participants' homes is the fastest surveillance instrument there is. During Project PROTECTS, thousands of participants held rapid tests and PCR collection kits while H5N1 spread through cattle and poultry with occasional human cases. Had it begun to spread in people, testing and symptom data collection could have been deployed across the cohort within days, ahead of conventional surveillance. We design our cohorts to be that ready.

Rapid, well-designed surveys of the general population or defined subpopulations, online and by phone, designed and weighted by epidemiologists rather than by a polling shop. On their own, or as the denominator that makes a cohort interpretable. Where it helps, we bring in other data streams: mobility data, claims, electronic health records and surveillance registries.

We help health departments, quality and review contractors, and program funders find out whether programs are working and for whom. That means evaluation designs that hold up, including pragmatic and stepped-wedge trials, careful use of program, clinical and surveillance data, and analysis that gets as close to causal answers as the data allow.

• Program evaluation design
• Clinical and program data review
• Surveillance data systems and dashboards
• Statistical analysis and peer review of complex analyses
• Interpretation and reporting

HIV is a particular strength. Denis Nash directed HIV/AIDS surveillance for New York City, and the team has led evaluations of New York City's Ryan White HIV care programs, built public Ending the HIV Epidemic data dashboards, and run HIV care and treatment cohort studies in more than 20 countries in sub-Saharan Africa. We can field a bench of HIV specialists across treatment, prevention, PrEP and PEP, and health equity.

Public health agencies are a core part of our work, and we know how they operate because we have worked inside them. Denis Nash began as a CDC Epidemic Intelligence Service officer and directed HIV/AIDS surveillance for New York City. Since then the team has carried out CDC- and NIH-funded research, served as a long-standing academic partner to the New York City Department of Health and Mental Hygiene, built New York State's Ending the Epidemic dashboard, and run wastewater surveillance across New York City's public hospitals.

For health departments and federal agencies, we offer:

• Surveillance system design and review
• Program evaluations
• Rapid epidemiologic studies
• Outbreak and emerging-threat response support
• Data systems and public dashboards
• Technical assistance and training

We can work as a prime contractor or as a scientific partner on a larger team.

Senior epidemiologic input at any stage: protocol and study design review, surveillance system design, technical assistance on public health data systems and dashboards, analysis and interpretation, systematic and rapid literature reviews, scientific advisory boards, and expert review.

More than twenty years of cohort research on HIV care and treatment in sub-Saharan Africa, including the IeDEA consortium, and an active network of academic collaborators across Africa, Europe and Asia. For sponsors and agencies working in low- and middle-income settings, we bring study design, cohort methods and implementation science experience earned on the ground, and collaborators who can run the work locally.

Denis Nash leads a team of highly qualified scientists and investigators, assembled to fit each project, and Sarah Kulkarni leads operations. The core team are epidemiologists, data scientists and study coordinators who have run the studies described on this site. Laboratory testing, sequencing, kit fulfillment and shipping are handled by long-standing partners.

Not every engagement is a study. Advisory and analytic work is scoped to what the client needs. Where we run a study, we agree on publication terms up front: protocols and analysis plans fixed in advance, and sponsor review for accuracy and confidentiality.