Bjonholme et al.
Tick-borne encephalitis in pregnant women: A mini narrative review
New Microbe and New Infect. 2022; 48:101017. doi: 10.1016/j.nmni.2022.101017

TBE virus infections during pregnancy have so far only rarely been reported. A Swedish team has observed two TBE cases in pregnant women.

Patient 1 was a 30-year-old patient, 31+6 weeks pregnant. She was presented to the labor ward with various clinical symptoms (including headache, tiredness, neck stiffness and fever) and reduced fetal movement. Various viral and bacterial infections were diagnostically excluded. The patient was IgM and IgG TBE positive, as well as TBE virus PCR positive. The infant was born preterm in week 36+5 and required external ventilation. The newborn was TBE IgG ELISA positive and had low neutralizing antibody titers. Antibody titers became negative during the following nine months.

Patient 2 was a 31-year-old woman, who was 26 weeks pregnant. She developed fever, headache and neck pain. Laboratory examination revealed TBE IgM and IgG seropositivity. The patient gave birth to a healthy infant week 39+5 with no complications after birth. The infant had TBE IgM and high IgG ELISA antibody titers at delivery.

In both cases, transplacental transmission of IgG was documented with decreasing titers over time. Both infants were IgM negative, which was expected because IgM does not significantly cross the placenta.

Both families were instructed to vaccinate their children against TBE after one year of age. The authors stated that obstetricians working in TBE high-endemic areas should be aware of the disease and that pregnant women can be vaccinated against TBE during pregnancy.

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