OBJECTIVES: The Laboratory Response Network (LRN) consists of US and international laboratories that respond to public health emergencies, such as biothreats. We used a qualitative approach to assess the successes and challenges of the LRN during the initial 10 weeks of the 2022 mpox outbreak (May 17-July 31, 2022). METHODS: We conducted 9 unstructured interviews, which included 3 interviews with subject matter experts from the Centers for Disease Control and Prevention (CDC) and 6 interviews with state and local public health laboratories and epidemiologists and Association of Public Health Laboratories (APHL) staff. We asked guiding questions on investments in preparedness, successes, and challenges during the initial mpox response and asked for suggestions to improve future LRN responses to infectious disease outbreaks. We also reviewed data from 2 contemporaneous APHL surveys conducted in June and July 2022 in 84 LRN public health laboratories. RESULTS: Notable successes included availability of an assay that had received clearance from the US Food and Drug Administration (FDA) for testing orthopoxviruses (non-variola Orthopoxvirus [NVO] assay) and a trained workforce; strong relationships among FDA, CDC, and the LRN; and strong communications between LRN laboratories and CDC. Challenges included variability among LRN laboratories in self-reported testing capacity, barriers to accessing the NVO assay for health care providers, and gaps in LRN function during surges of testing needs. CONCLUSIONS: The LRN system plays an essential role in the response to emerging infectious disease outbreaks in the United States. Lessons learned from the LRN's initial response to the mpox outbreak can help guide improvements to better position the LRN for future responses, including continued engagement with health care providers, commercial laboratories, and laboratories in health care settings.

To assess household transmission of pandemic (H1N1) 2009 in San Antonio, Texas, USA, during April 15-May 8, 2009, we investigated 77 households. The index case-patient was defined as the household member with the earliest onset date of symptoms of acute respiratory infection (ARI), influenza-like illness (ILI), or laboratory-confirmed pandemic (H1N1) 2009. Median interval between illness onset in index and secondary case-patients was 4 days (range 1-9 days); the index case-patient was likely to be < or =18 years of age (p = 0.034). The secondary attack rate was 4% for pandemic (H1N1) 2009, 9% for ILI, and 13% for ARI. The secondary attack rate was highest for children <5 years of age (8%-19%) and lowest for adults > or =50 years of age (4%-12%). Early in the outbreak, household transmission primarily occurred from children to other household members and was lower than the transmission rate for seasonal influenza.