Studies suggest the burden of non-hospitalized severe respiratory illness might be substantial in Kenya. Using data from a Kenya COVID-19 vaccine effectiveness evaluation, we compared characteristics of patients aged ≥12 years who were hospitalized with severe respiratory illness to outpatients who were referred for hospitalization and declined (non-hospitalized). Symptom presentation and lung radiograph findings were similar among both groups, and patients in both were diagnosed with critical conditions, including acute respiratory distress syndrome (12% hospitalized; 4% non-hospitalized) and sepsis (10% both). Findings underscore the importance of including non-hospitalized severe illness when estimating the burden of disease for respiratory viruses. © 2025 Elsevier B.V., All rights reserved.

While seasonal influenza vaccines (SIV) remain the best method to prevent influenza-associated illnesses, implementing SIV programs may benefit countries beyond disease reduction, strengthening health systems and national immunization programs, or conversely, introduce new challenges. Few studies have examined perceived impacts of SIV introduction beyond disease reduction on health systems; understanding such impacts will be particularly salient in the context of COVID-19 vaccine introduction. We collected qualitative data from key informants-Partnership for Influenza Vaccine Introduction (PIVI) contacts in six middle-income PIVI vaccine recipient countries-to understand perceptions of ancillary benefits and challenges from SIV implementation. Respondents reported benefits associated with SIV introduction, including improved attitudes to SIV among risk groups (characterized by increased demand) and perceptions that SIV introduction improved relationships with other ministries and collaboration with mass media. Challenges included sustaining investment in SIV programs, as vaccine supply did not always meet coverage goals, and managing SIV campaigns.