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Published on: October 10, 2025
Severe pathogenesis of influenza B virus in pregnant mice
Jeong Cheol Kim1, Heui Man Kim, Young Myong Kang
1Laboratory of Influenza Research, College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, Republic of Korea; Institute for Influenza Virus, College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, Republic of Korea.
The study on pathogenesis of influenza B virus during pregnancy is limited. Here, we showed using a mouse model that influenza B virus could cause severe disease including death during pregnancy. Infected pregnant mice resulted in 40% mortality, but infected age-matched non-pregnant mice did not show any death. Infected pregnant mice contained high viral loads in lungs with the elevated inductions of inflammatory cytokines and chemokines than infected non-pregnant mice. Infected pregnant mice delivered lower number of neonates than uninfected pregnant mice, suggesting adverse effects of influenza B virus on fetuses. Progesterone which is important for maintaining pregnancy was reduced in uteruses of infected pregnant mice than in those of uninfected pregnant mice. Taken together, our results suggest that influenza B virus can cause severe disease during pregnancy, and that preventive measures including vaccination may be important for protecting women during pregnancy.
The study on pathogenesis of influenza B virus during pregnancy is limited. Here, we showed using a mouse model that influenza B virus could cause severe disease including death during pregnancy. Infected pregnant mice resulted in 40% mortality, but infected age-matched non-pregnant mice did not show any death. Infected pregnant mice contained high viral loads in lungs with the elevated inductions of inflammatory cytokines and chemokines than infected non-pregnant mice. Infected pregnant mice delivered lower number of neonates than uninfected pregnant mice, suggesting adverse effects of influenza B virus on fetuses. Progesterone which is important for maintaining pregnancy was reduced in uteruses of infected pregnant mice than in those of uninfected pregnant mice. Taken together, our results suggest that influenza B virus can cause severe disease during pregnancy, and that preventive measures including vaccination may be important for protecting women during pregnancy.
