The surge of respiratory syncytial virus (RSV) experienced in the fall and winter of 2022 occurred throughout the world. One place heavily affected in 2022, with a four-fold surge, was Sydney, Australia. In an article being early released this month in Pediatrics, Walker et al. (10.1542/peds.2023-063667) explored whether the uptick in cases was due to a new genetic RSV variant or if the isolation during the pandemic led more infants to being vulnerable because their mothers lacked neutralizing antibodies.
To investigate these possibilities, the authors obtained genome sequences of RSV from 264 RSV-infected infants less than a year of age and matched them with RSV case-matched clinical phylogenetic data obtained during from 2017 through 2022. The authors also measured humoral immunity (neutralizing antibodies against RSV) of women of childbearing age before and during this time period.
Interestingly, there were not substantive phylogenetic differences between 2022 and viruses circulating globally since 2017 in both the southern and northern hemispheres. There was also no difference in neutralizing antibody titers in child-bearing women between 2020 and 2022. The authors conclude that the surge was not due to a new RSV genotype or because an infant did not have adequate passive protection. What caused the surge and how might we prevent a similar surge in the future? The authors provide some interesting thoughts in light of their negative findings in the Discussion section of their article. They also note limitations of their findings, such as the use of only a single children’s hospital for their sample. The authors suggest that the factors leading to the surge are complex and highlight the exciting new opportunities related to RSV vaccination. Go to the link for this study and learn more.
