Background: This report summarizes the discussions and conclusions from the “Correlates of Protection for Next Generation Influenza Vaccines: Lessons Learned from the COVID-19 Pandemic” meeting which took place in Seattle, USA, from March 1, 2023, to March 3, 2023. Conclusions: Discussions around influenza virus correlates of protection and their use continued from where the discussion had been left off in 2019. While there was not much progress in the influenza field itself, many lessons learned during the coronavirus disease 2019 (COVID-19) pandemic, especially the importance of mucosal immunity, were discussed and can directly be applied to influenza correlates of protection.

Novel human astrovirus (HAstV) strains have been recently shown to cause fatal encephalitis in immunocompromised patients. We report two cases from our institution. A 2-year old female undergoing treatment for acute lymphoblastic leukemia and a 9-year old male with refractory acute myeloid leukemia. Both were found to have HAstV-VA1 in the cerebrospinal fluid (CSF) by metagenomics next generation sequencing (m-NGS) after the initial evaluation did not reveal any etiology. Patient 1 remains alive, in remission, showing gradual neurological improvement after treatment with steroids, intravenous immunoglobulin, ribavirin, nitazoxanide and Peg-INF-alpha 2b. Patient 2 died 7 weeks later while receiving palliative care.