PAIR Distinguished Lecture by Prof Alexandria Boehm (29 Jun 2026)

Tracking influenza transmission through wastewater: Stanford research reveals new opportunities for public health On 29 June 2026, Prof. Alexandria BOEHM of Stanford University, U.S., delivered a PAIR Distinguished Lecture titled “Influenza Transmission and Diversity in Humans and Animals Inferred from Untreated Wastewater across the United States”. The lecture attracted more than 80 attendees in person, while approximately 15,600 viewers watched the livestream across multiple social media platforms. During the lecture, Prof. Boehm highlighted the important role of wastewater surveillance in monitoring infectious diseases and explained how viral signals can provide timely insights into trends of community transmission. She noted that Influenza A RNA detected in wastewater solids can effectively reflect seasonal influenza transmission patterns and accurately track the beginning, peak, and end of flu seasons. These data not only help monitor outbreak developments but also provide valuable references for clinical decision-making and public health communication. Prof. Boehm further pointed out that Influenza A RNA concentrations in wastewater closely correspond to community infection patterns. The wastewater surveillance programme she leads, WastewaterSCAN, began as a pilot project at just two sites and has since expanded to more than 150 wastewater treatment plants across 40 U.S. states. Data accumulated over years of surveillance have not only revealed patterns of influenza transmission across seasons and regions, but also demonstrated close associations between influenza activity and other respiratory viruses such as respiratory syncytial virus (RSV). The lecture also explored how wastewater surveillance can be used to identify influenza virus subtypes. Prof. Boehm explained that while total Influenza A RNA levels can reflect outbreak trends, subtype information is equally essential for assessing vaccine effectiveness and disease severity. By analysing haemagglutinin (HA) and neuraminidase (NA) gene sequences, researchers can identify currently circulating virus subtypes—including H3N2, H1N1, and H5N1—from wastewater samples, enabling a more comprehensive understanding of the distribution and transmission of different influenza strains. Beyond reflecting human infections, animal influenza signals detected in wastewater also provide valuable insights for disease transmission monitoring. Prof. Boehm explained that these data help track the progression of avian influenza outbreaks in U.S. cattle and assess transmission risks among animals. With advances in metagenomic technologies, researchers are now able to assemble novel influenza virus genomes from wastewater samples, offering deeper insights into how these viruses evolve over time. Prof. Boehm emphasised that understanding circulating virus subtypes can support more effective vaccine development and help anticipate potential viral reassortment events at an early stage, strengthening preparedness for emerging threats. She concluded that continued advances in wastewater surveillance may eventually help predict which influenza gene sequences are likely to circulate, providing a stronger scientific basis for preventive vaccine development, including the selection of strains for future seasonal vaccines. The lecture concluded with a Q&A session moderated by Prof. LI Xiangdong, Director of the Research Institute for Sustainable Urban Development. Both in-person and online participants had lively discussions with Prof. Boehm, exploring topics ranging from wastewater surveillance to influenza prevention and control.