This is a summary, written by members of the CITF Secretariat, of:

Abu-Raya B, Reicherz F, Michalski C, Viñeta Paramo M, Majdoubi A, Golding L, Granoski M, Stojic A, Marchant DJ, Lavoie PM. Loss of Respiratory Syncytial Virus Antibody Functions During the Peak of the COVID-19 Pandemic Mitigation Measures. J Pediatric Infect Dis Soc. 2023 Nov 8:piad099. doi: 10.1093/jpids/piad099.

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

A CITF-funded study, published in the Journal of the Pediatric Infectious Diseases Society, showed that specific antibody immune characteristics previously linked to more severe respiratory syncytial virus (RSV) infections waned among women of childbearing age in 2020-2021. This period was characterised by COVID-19 mitigation measures that resulted in reduced RSV circulation.

The research team specifically found that antibody functions – namely “phagocytosis”, a process by which immune cells engulf viruses, and “complement deposition”, a process that impedes viral entry into cells by labeling viral particles – waned between spring 2020 and spring 2021, in absence of RSV cases. Since antibodies transferred during pregnancy are important to protect young infants against RSV, these observations could explain why more severe RSV cases are being observed over subsequent years among young children in BC and Canada.

Key findings:

  • Both Antibody-dependent cellular phagocytosis (geometric mean phagocytosis score: 228.7 vs. 685.5) and antibody-dependent complement deposition (geometric mean: 1.26 vs. 62.8) scores significantly decreased in 2021 compared to 2020.
  • The samples collected in 2020 and 2021 showed a unique cluster that displayed lower antibody-dependent cellular phagocytosis and a unique subset of people with lower antibody- dependent complement deposition using clustering methods.

Overall, this study sheds light on the longevity of antibody-mediated immunity against RSV during a prolonged period of lack of viral circulation and adds to the evidence that protective RSV immunity is short-lived. Researchers have highlighted that further studies are needed to understand how antibody functions are restored after viral re-exposure.

Multi-dimensional immune function analyses were performed on a small sample of 18 paired serum samples collected from the women of childbearing aged 18-51 years (median age 37 years) at BC Children’s & Women’s Health Centre in Vancouver from May to June 2020, and from February to May 2021.