BACKGROUND: Rapid, accessible, and accurate testing was paramount to an effective US COVID-19 response. Federal partners supported SARS-CoV-2 testing scale-up through an interagency-coordinated approach that focused on expanding supply chains, research and development, validation, and improving patient access. We aimed to provide an overview of the federal efforts to scale up the testing response and study the impact of scale-up. METHODS: In this descriptive analysis, we mapped federal partner activities and milestones using the US Government Testing and Diagnostics Working Group (TDWG) and participating agency and department data from Jan 1, 2020, to Dec 31, 2022. Tests produced (TDWG), reported test positivity (US Centers for Disease Control and Prevention [CDC]'s COVID-19 Electronic Laboratory Reporting system and the Federal Direct Report testing data), reported COVID-19 case counts (CDC), hospitalisations (Department of Health and Human Services Unified Hospital Data Surveillance System and the CDC's National Healthcare Safety Network), and deaths (CDC) were analysed over time. We then developed an agent-based model to evaluate the impact testing had on COVID-19 outcomes using different scenarios. The scenarios were (1) if efforts led to substantially fewer tests produced, (2) if scale-up was delayed, affecting test access, and (3) if efforts led to substantially more tests produced. FINDINGS: Approximately 6·7 billion SARS-CoV-2 tests, including over 1·5 billion laboratory-based, 1·9 billion point-of-care (POC), and 3·2 billion over-the-counter (OTC) tests, were produced, and approximately 2·7 billion tests were performed between Jan 1, 2020, and Dec 31, 2022. Testing capacity exhibited various expansion phases, with laboratory-based capacity growing from approximately 6 million tests per month in March, 2020 to approximately 34 million tests per month in July, 2020; POC increased to approximately 126 million tests per month by December, 2020, and OTC increased to approximately 986 million tests per month by February, 2022. Comparison between the baseline (actual) and delay-in-testing scenario suggests the increased testing capacity potentially saved upwards of 1·4 million lives and averted 7 million hospitalisations. INTERPRETATION: Our study suggests that early development, manufacturing, and distribution of tests had a great impact on reducing severe COVID-19 outcomes. These results highlight the importance of robust and rapid test development, production, and distribution when addressing future public health threats. FUNDING: US Administration for Strategic Preparedness and Response and US Centers for Disease Control and Prevention.

Pertussis, caused by Bordetella pertussis, can cause debilitating respiratory symptoms, so whole-cell pertussis vaccines (wPVs) were introduced in the 1940s. However, reactogenicity of wPV necessitated the development of acellular pertussis vaccines (aPVs) that were introduced in the 1990s. Since then, until the COVID-19 pandemic began, reported pertussis incidence was increasing, suggesting that aPVs do not induce long-lasting immunity and may not effectively prevent transmission. Additionally, aPVs do not provide protection against other Bordetella species that are observed during outbreaks. The significance of this work is in determining potential new vaccine antigens for multiple Bordetella species that are predicted to elicit long-term immune responses. Genome-based approaches have aided the development of novel vaccines; here, these methods identified Bordetella vaccine candidates that may be cross-protective and predicted to induce strong memory responses. These targets can lead to an improved vaccine with a strong safety profile while also strengthening the longevity of the immune response.