Despite the development of the Model Aquatic Health Code (MAHC), U.S. public health departments and aquatics agencies face obstacles in incorporating this guidance into their pool codes. A cross comparison of five state pool codes with the MAHC was conducted to quantify MAHC incorporation into these state codes. The proportion of MAHC code agreement with state codes in this study had a range of 14%–86%. Only 2% of all the MAHC codes available were present in all five state codes, conversely, 12% of the MAHC codes were not found in any state. These differences in code agreement highlight the challenge of measuring MAHC effectiveness at the national level. To improve aquatic safety at a national level, a potential solution is development and use of common core elements in state and local pool codes. Once there is a basis for code comparisons across states, public health programs can investigate whether core MAHC codes result in reduced waterborne illness outbreaks, drowning incidents, injuries from pool chemicals, health outcomes from exposure to disinfection by-products, and swimming-related emergency department visits. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Swimming and other water-related activities are excellent ways to get the physical activity and health benefits needed for a healthy life. In the United States, we swim and bathe over 300 hundred million times in pools, oceans, lakes, rivers, and hot tubs/spas each year and most of the time it is healthy, safe, and enjoyable. However, there are risks associated with swimming and other recreational water activities. The number of outbreaks associated with recreational water has increased substantially over the last few decades. Drowning, near-drowning and pool chemical injuries continue to occur (See Table 1). This underscores the need to build, maintain, and inspect public pools, hot tubs/spas, and waterparks to help keep bathers and aquatics staff healthy and safe.

A 38-year-old female patient with systemic lupus erythematosus presented with pulmonary infiltrates and hypoxemia for several months following immunodepleting autologous hematopoietic stem cell transplantation. She was treated for influenza, which was isolated repeatedly from oropharynx and bronchoalveolar lavage (BAL) fluids, and later empirically for lupus pneumonitis, but died 6 months after transplant. Autopsy findings failed to show influenza in the lungs or lupus pneumonitis. A novel generic polymerase chain reaction (PCR)-based assay using degenerate primers identified human coronavirus (CoV) HKU1 RNA in BAL fluid at autopsy. CoV was confirmed by virus-specific PCRs of lung tissue at autopsy. Electron microscopy showed viral particles consistent with CoV HKU1 in lung tissue both at autopsy and from a previous biopsy. Although human CoV HKU1 infection is not usually severe, in highly immunocompromised patients, it can be associated with fatal pneumonia.