Can the Flu Trigger Narcolepsy?

Influenza A(H1N1)pdm09 and influenza B viruses (IBV) may trigger narcolepsy with cataplexy (NC), according to a late-breaking study to be presented at SLEEP 2024, taking place June 1-5 in Houston, Texas.

Although H1N1 infection may induce NC, the seasonal onset of NC and common childhood cases in China prior to 2009 and increased cases of NC following 2009 independent of H1N1 epidemics remain unexplained. According to the investigators, this fact suggests other triggers in NC pathogenesis.

In their study, researchers used a nationwide surveillance network of narcolepsy and flu data from China to analyze 2358 patients in 4 steps. First, they correlated seasonal and annual NC incidence (2000-2003) with SARS (2003) and COVID-19 (2020-2022). Second, seasonal patterns of NC onset in both North and South China were characterized using spatial analysis. Third, the link between causation of NC onset with influenza activity (2005-2013) was assessed using temporal analysis. Last, researchers used influenza antibody testing to discern the specific flu infection as a risk of NC.

According to the results, the annual NC onset had a prominent peak in 2010 following H1N1 and 2 troughs in 2004 and 2021 following SARS and COVID-19 control measures. The seasonal NC onset was observed to be high in the spring and
summer and low in winter. Overall, the study showed that in addition to H1N1, B/Victoria and B/Yamagata were also triggers for NC, especially in children, with a gap of 5 months for H1N1, and 3 to 4 months for IBV between
pandemic and NC onset.

“H1N1 and IBV, but not COVID-19, are triggers for NC, highlighting the significance of IBV infection, particularly in children who are more vulnerable and have more severe symptoms. New IBV antigens may help illustrate immune-mediated mechanisms of orexin/hypocretin neuronal destruction in NC,” the researchers concluded.

Reference

Han F. Influenza A(H1N1) pdm09 and B viruses but not COVID-19 as triggers for narcolepsy with cataplexy. LBA #1272. Presented at SLEEP 2024; June 1-5, 2024; Houston, Texas.